Abstract: Cold stress is an important environmental factor that affects plant growth and development as well as plant distribution. The CBF-dependent cold signaling pathway has been extensively studied. In this review, we summarize the latest advances in research of CBF genes, revealing the important role of CBFs in freezing tolerance and in chilling resistance of plants. The understanding of the CBF regulatory mechanism network at multiple levels will provide new insights into how CBF-mediated cold signaling balances tolerance and growth in plants, which may help to improve cold- stress tolerance in crops.
Key words:CBF transcription factors ; cold stress ; freezing tolerance ; growth and development
图1 CBF依赖的低温信号途径 实线代表直接调控, 虚线代表间接调控。箭头代表正调控, T型箭头代表负调控。 Figure 1 CBF-dependent cold signaling pathway The solid lines indicate direct regulation, and dotted lines indicate indirect regulation. Positive regulation is indicated by arrow heads and negative regulation is indicated by T-shaped lines.
4 CBF在植物生长发育中的作用一系列研究表明CBF参与植物的生长发育过程。过表达CBF导致植株矮小, 且与野生型相比, 开花时间明显延迟(Gilmour et al., 2004; Park et al., 2015)。对突变体的研究表明, cbf1/cbf2/cbf3三突变体种子萌发率与野生型相比降低一半, 根生长速率略慢于野生型, 植株的莲座叶数目减少, 形态偏小, 生物量也低于野生型(Zhao et al., 2016)。这些结果说明, CBF是植物生长发育过程中的关键因素。Jia等(2016)研究表明, 低温下无论是土中还是培养皿上生长的cbf1/cbf2/cbf3三突变体植株均明显大于野生型, 说明CBF影响了低温胁迫下植物的生长发育(Jia et al., 2016)。有趣的是, 外源施加影响植物细胞伸长的植物激素赤霉素(gibberellin acid, GA)可以回复CBF1过表达植株的生长发育矮小表型(Achard et al., 2008)。过表达CBF1可以激活植物体内GA2ox基因的表达, 使植物体内活性形式的GA含量下降, 造成GA信号途径的负调节因子DELLA蛋白在植物体内高水平积累, 从而导致植株生长受到抑制。DELLA基因突变可以部分回复CBF1过表达植株的矮小表型, 这些结果暗示, CBF在生长发育中的作用需要GA及DELLA蛋白的参与(Achard et al., 2008)。不仅CBF影响植物的生长发育, CBF的上游调控因子如ICE1、ICE2、EIN3、BZR1、PIF3/4/7和SOC1等也全部参与调控植物的生长发育, 突变体均表现出各种生长发育表型, 这暗示着植物产生对低温胁迫的抗性很可能需要以牺牲生长发育作为代价。最新研究表明, 植物面对低温胁迫时, 会自主启动细胞死亡机制, 优先杀死未成熟的小柱干细胞, 使根部静止中心维持高浓度生长素, 有利于干细胞巢(stem cell niche)抵抗低温胁迫(Hong et al., 2017)。但这一机制具有特异性, CBF是否参与这一过程目前仍有待研究。植物面对低温或者其它胁迫可能要做出选择: 是继续正常生长发育从而造成对胁迫的敏感, 还是牺牲生长发育, 利用更多能量产生抵抗物质来对抗逆境? CBF可能参与低温胁迫及生长发育调控, 寻找到一种平衡植物抗冻及生长发育受损的调控机制可能是后续需要认真研究的科学问题。 另一个非常值得关注的问题是作用于CBF最上游的植物低温感受器究竟是什么? 2015年, 种康课题组通过QTL发现水稻中的COLD1基因介导粳稻耐冷性(Ma et al., 2015)。COLD1定位在细胞质膜和内质网膜上, 与拟南芥中G蛋白α亚基互作蛋白GTG1/2高度同源, 被认为是一个低温感受器。它通过与G蛋白α亚基互作, 影响G蛋白活性, 调控低温激活的Ca2+内流, 从而影响籼稻的耐冷性。基因表达分析显示COLD1的互补株系中CBF基因表达上调, 说明COLD1可能参与CBF的调控。该基因上的1个SNP是影响水稻耐冷的关键位点, 暗示COLD1基因在自然选择过程中的重要性(Ma et al., 2015)。那么除此之外是否还有其它的低温感受器存在? 蓝藻中的温度感受器Hik33是一类组蛋白激酶(Zabulon et al., 2007; Shimura et al., 2012)。植物中的组蛋白激酶作为激素受体发挥重要作用, 它们是否也是低温的感受器? 还有研究表明光受体phyB作为温度感受器调控植物对室温环境温度的感受(Jung et al., 2016; Legris et al., 2016), 但其是否参与低温的感受仍不清楚, 这些问题都有待进一步验证。
The authors have declared that no competing interests exist.
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JungJH, DomijanM, KloseC, BiswasS, EzerD, GaoMJ, KhattakAK, BoxMS, CharoensawanV, CortijoS, KumarM, GrantA, LockeJCW, Sch?ferE, JaegerKE, WiggePA (2016). Phytochromes function as thermosensors in Arabidopsis.Science 354, 886-889. DOI:10.1126/science.aaf6005PMID:27789797URLAbstract Plants are responsive to temperature, and some species can distinguish differences of 100°C. In Arabidopsis, warmer temperature accelerates flowering and increases elongation growth (thermomorphogenesis). However, the mechanisms of temperature perception are largely unknown. We describe a major thermosensory role for the phytochromes (red light receptors) during the night. Phytochrome null plants display a constitutive warm-temperature response, and consistent with this, we show in this background that the warm-temperature transcriptome becomes derepressed at low temperatures. We found that phytochrome B (phyB) directly associates with the promoters of key target genes in a temperature-dependent manner. The rate of phyB inactivation is proportional to temperature in the dark, enabling phytochromes to function as thermal timers that integrate temperature information over the course of the night. Copyright 0008 2016, American Association for the Advancement of Science. [本文引用: 1]
[28]
KasugaM, LiuQ, MiuraS, Yamaguchi-ShinozakiK, ShinozakiK (1999). Improving plant drought, salt, and freezing tolerance by gene transfer of a single stress-inducible transcription factor.Nat Biotechnol 17, 287-291. DOI:10.1038/7036PMID:10096298URLAbstract Plant productivity is greatly affected by environmental stresses such as drought, salt loading, and freezing. We reported previously that a cis-acting promoter element, the dehydration response element (DRE), plays an important role in regulating gene expression in response to these stresses. The transcription factor DREB1A specifically interacts with the DRE and induces expression of stress tolerance genes. We show here that overexpression of the cDNA encoding DREB1A in transgenic plants activated the expression of many of these stress tolerance genes under normal growing conditions and resulted in improved tolerance to drought, salt loading, and freezing. However, use of the strong constitutive 35S cauliflower mosaic virus (CaMV) promoter to drive expression of DREB1A also resulted in severe growth retardation under normal growing conditions. In contrast, expression of DREB1A from the stress inducible rd29A promoter gave rise to minimal effects on plant growth while providing an even greater tolerance to stress conditions than did expression of the gene from the CaMV promoter. [本文引用: 1]
[29]
KasugaM, MiuraS, ShinozakiK, Yamaguchi-ShinozakiK (2004). A combination of the Arabidopsis DREB1A gene and stress-inducible rd29A promoter improved drought- and low-temperature stress tolerance in tobacco by gene transfer. Plant Cell Physiol 45, 346-350. [本文引用: 2]
[30]
KidokoroS, YonedaK, TakasakiH, TakahashiF, ShinozakiK, Yamaguchi-ShinozakiK (2017). Different cold- signaling pathways function in the responses to rapid and gradual decreases in temperature.Plant Cell 29, 760-774. DOI:10.1105/tpc.16.00669PMID:28351986URLAbstract In plants, cold temperatures trigger stress responses and long-term responses that result in cold tolerance. In Arabidopsis thaliana , three dehydration-responsive element (DRE) binding protein 1/C-repeat binding factors (DREB1/CBFs) act as master switches in cold-responsive gene expression. Induction of DREB1 genes triggers the cold stress-inducible transcriptional cascade, followed by the induction of numerous genes that function in the cold stress response and cold tolerance. Many regulatory factors involved in DREB1 induction have been identified, but how these factors orchestrate the cold stress-specific expression of DREB1s has not yet been clarified. Here, we revealed that plants recognize cold stress as two different signals, rapid and gradual temperature decreases, and induce expression of the DREB1 genes. CALMODULIN BINDING TRANSCRIPTION ACTIVATOR3 (CAMTA3) and CAMTA5 respond to a rapid decrease in temperature and induce the expression of DREB1s , but these proteins do not respond to a gradual decrease in temperature. Moreover, they function during the day and night, in contrast to some key circadian components, including CIRCADIAN CLOCK ASSOCIATED1 and LATE ELONGATED HYPOCOTYL, which regulate cold-responsive DREB1 expression as transcriptional activators only during the day. Thus, plants efficiently control the acquisition of freezing tolerance using two different signaling pathways in response to a gradual temperature decrease during seasonal changes and a sudden temperature drop during the night. 2017 American Society of Plant Biologists. All rights reserved. [本文引用: 2]
[31]
KimSH, KimHS, BahkS, AnJ, YooY, KimJY, ChungWS (2017). Phosphorylation of the transcriptional repressor MYB15 by mitogen-activated protein kinase 6 is required for freezing tolerance in Arabidopsis.Nucleic Acids Res 45, 6613-6627. DOI:10.1093/nar/gkx417PMID:28510716URLAbstract The expression of CBF (C-repeat-binding factor) genes is required for freezing tolerance in Arabidopsis thaliana. CBFs are positively regulated by INDUCER OF CBF EXPRESSION1 (ICE1) and negatively regulated by MYB15. These transcription factors directly interact with specific elements in the CBF promoters. Mitogen-activated protein kinase (MAPK/MPK) cascades function upstream to regulate CBFs. However, the mechanism by which MPKs control CBF expression during cold stress signaling remains unknown. This study showed that the activity of MYB15, a transcriptional repressor of cold signaling, is regulated by MPK6-mediated phosphorylation. MYB15 specifically interacts with MPK6, and MPK6 phosphorylates MYB15 on Ser168. MPK6-induced phosphorylation reduced the affinity of MYB15 binding to the CBF3 promoter and mutation of its phosphorylation site (MYB15S168A) enhanced the transcriptional repression of CBF3 by MYB15. Furthermore, transgenic plants overexpressing MYB15S168A showed significantly reduced CBF transcript levels in response to cold stress, compared with plants overexpressing MYB15. The MYB15S168A-overexpressing plants were also more sensitive to freezing than MYB15-overexpressing plants. These results suggest that MPK6-mediated regulation of MYB15 plays an important role in cold stress signaling in Arabidopsis. [本文引用: 1]
[32]
KimY, ParkS, GilmourSJ, ThomashowMF (2013). Roles of CAMTA transcription factors and salicylic acid in configuring the low-temperature transcriptome and freezing tolerance of Arabidopsis.Plant J 75, 364-376. DOI:10.1111/tpj.12205PMID:23581962URLPrevious studies in Arabidopsis thaliana established roles for CALMODULIN BINDING TRANSCRIPTION ACTIVATOR 3 (CAMTA3) in the rapid cold induction of CRT/DRE BINDING FACTOR (CBF) genes CBF1 and CBF2, and the repression of salicylic acid (SA) biosynthesis at warm temperature. Here we show that CAMTA1 and CAMTA2 work in concert with CAMTA3 at low temperature (4°C) to induce peak transcript levels of CBF1, CBF2 and CBF3 at 2 h, contribute to up-regulation of approximately 15% of the genes induced at 24 h, most of which fall outside the CBF pathway, and increase plant freezing tolerance. In addition, CAMTA1, CAMTA2 and CAMTA3 function together to inhibit SA biosynthesis at warm temperature (22°C). However, SA levels increase in Arabidopsis plants that are exposed to low temperature for more than 1 week. We show that this chilling-induced SA biosynthesis proceeds through the isochorismate synthase (ICS) pathway, with cold induction of ICS1 (which encodes ICS), and two genes encoding transcription factors that positively regulate ICS1 – CBP60g and SARD1 –, paralleling SA accumulation. The three CAMTA proteins effectively repress the accumulation of ICS1, CBP60g and SARD1 transcripts at warm temperature but not at low temperature. This impairment of CAMTA function may involve post-transcriptional regulation, as CAMTA transcript levels did not decrease at low temperature. Salicylic acid biosynthesis at low temperature did not contribute to freezing tolerance, but had a major role in configuring the transcriptome, including the induction of ‘defense response’ genes, suggesting the possible existence of a pre-emptive defense strategy programmed by prolonged chilling temperatures. [本文引用: 1]
[33]
LeeBH, HendersonDA, ZhuJK (2005). The Arabidopsis cold-responsive transcriptome and its regulation by ICE1.Plant Cell 17, 3155-3175. DOI:10.1105/tpc.105.035568PMID:16214899URLTo understand the gene network controlling tolerance to cold stress, we performed an Arabidopsis thaliana genome transcript expression profile using Affymetrix GeneChips that contain 24,000 genes. We statistically determined 939 cold-regulated genes with 655 upregulated and 284 downregulated. A large number of early cold-responsive genes encode transcription factors that likely control late-responsive genes, suggesting a multitude of transcriptional cascades. In addition, many genes involved in chromatin level and posttranscriptional regulation were also cold regulated, suggesting their involvement in cold-responsive gene regulation. A number of genes important for the biosynthesis or signaling of plant hormones, such as abscisic acid, gibberellic acid, and auxin, are regulated by cold stress, which is of potential importance in coordinating cold tolerance with growth and development. We compared the cold-responsive transcriptomes of the wild type and inducer of CBF expression 1 (ice1), a mutant defective in an upstream transcription factor required for chilling and freezing tolerance. The transcript levels of many cold-responsive genes were altered in the ice1 mutant not only during cold stress but also before cold treatments. Our study provides a global picture of the Arabidopsis cold-responsive transcriptome and its control by ICE1 and will be valuable for understanding gene regulation under cold stress and the molecular mechanisms of cold tolerance. [本文引用: 1]
[34]
LeeCM, ThomashowMF (2012). Photoperiodic regulation of the C-repeat binding factor (CBF) cold acclimation pathway and freezing tolerance inArabidopsis thaliana. Proc Natl Acad Sci USA 109, 15054-15059. DOI:10.1073/pnas.1211295109PMID:22927419URLThe CBF (C-repeat binding factor) pathway has a major role in plant cold acclimation, the process whereby certain plants increase in freezing tolerance in response to low nonfreezing temperatures. In Arabidopsis thaliana, the pathway is characterized by rapid cold induction of CBF1, CBF2, and CBF3, which encode transcriptional activators, followed by induction of CBF-targeted genes that impart freezing tolerance. At warm temperatures, CBF transcript levels are low, but oscillate due to circadian regulation with peak expression occurring at 8 h after dawn (Zeitgeber time 8; ZT8). Here, we establish that the CBF pathway is also regulated by photoperiod at warm temperatures. At ZT8, CBF transcript levels in short-day (SD; 8-h photoperiod) plants were three-to fivefold higher than in long-day plants (LD; 16-h photoperiod). Moreover, the freezing tolerance of SD plants was greater than that of LD plants. Genetic analysis indicated that phytochrome B (PHYB) and two phytochrome-interacting factors, PIF4 and PIF7, act to down-regulate the CBF pathway and freezing tolerance under LD conditions. Down-regulation of the CBF pathway in LD plants correlated with higher PIF4 and PIF7 transcript levels and greater stability of the PIF4 and PIF7 proteins under LD conditions. Our results indicate that during the warm LD growing season, the CBF pathway is actively repressed by PHYB, PIF4, and PIF7, thus mitigating allocation of energy and nutrient resources toward unneeded frost protection. This repression is relieved by shortening day length resulting in up-regulation of the CBF pathway and increased freezing tolerance in preparation for coming cold temperatures. [本文引用: 2]
[35]
LegrisM, KloseC, BurgieES, RojasCCR, NemeM, HiltbrunnerA, WiggePA, Sch?ferE, VierstraRD, CasalJJ (2016). Phytochrome B integrates light and temperature signals in Arabidopsis.Science 354, 897-900. DOI:10.1126/science.aaf5656PMID:27789798URLAmbient temperature regulates many aspects of plant growth and development, but its sensors are unknown. Here, we demonstrate that the phytochrome B (phyB) photoreceptor participates in temperature perception through its temperature-dependent reversion from the active Pfr state to the inactive Pr state. Increased rates of thermal reversion upon exposing Arabidopsis seedlings to warm environments reduce both the abundance of the biologically active Pfr-Pfr dimer pool of phyB and the size of the associated nuclear bodies, even in daylight. Mathematical analysis of stem growth for seedlings expressing wild-type phyB or thermally stable variants under various combinations of light and temperature revealed that phyB is physiologically responsive to both signals. We therefore propose that in addition to its photoreceptor functions, phyB is a temperature sensor in plants. Authors: Martina Legris, Cornelia Klose, E. Sethe Burgie, Cecilia Costigliolo Rojas Rojas, Maximiliano Neme, Andreas Hiltbrunner, Philip A. Wigge, Eberhard Sch fer, Richard D. Vierstra, Jorge J. Casal [本文引用: 1]
[36]
LeivarP, MonteE (2014). PIFs: systems integrators in plant development.Plant Cell 26, 56-78. DOI:10.1105/tpc.113.120857URL [本文引用: 1]
[37]
LeivarP, MonteE, OkaY, LiuT, CarleC, CastillonA, HuqE, QuailPH (2008). Multiple phytochrome-interacting bHLH transcription factors repress premature seedling photomorphogenesis in darkness.Curr Biol 18, 1815-1823. DOI:10.1016/j.cub.2008.10.058PMID:19062289URLAn important contributing factor to the success of terrestrial flowering plants in colonizing the land was the evolution of a developmental strategy, termed skotomorphogenesis, whereby postgerminative seedlings emerging from buried seed grow vigorously upward in the subterranean darkness toward the soil surface. Here we provide genetic evidence that a central component of the mechanism underlying this strategy is the collective repression of premature photomorphogenic development in dark-grown seedlings by several members of the phytochrome (phy)-interacting factor (PIF) subfamily of bHLH transcription factors (PIF1, PIF3, PIF4, and PIF5). Conversely, evidence presented here and elsewhere collectively indicates that a significant component of the mechanism by which light initiates photomorphogenesis upon first exposure of dark-grown seedlings to irradiation involves reversal of this repression by rapid reduction in the abundance of these PIF proteins, through degradation induced by direct interaction of the photoactivated phy molecule with the transcription factors. We conclude that bHLH transcription factors PIF1, PIF3, PIF4, and PIF5 act as constitutive repressors of photomorphogenesis in the dark, action that is rapidly abrogated upon light exposure by phy-induced proteolytic degradation of these PIFs, allowing the initiation of photomorphogenesis to occur. [本文引用: 1]
[38]
LiH, DingYL, ShiYT, ZhangXY, ZhangSQ, GongZZ, YangSH (2017a). MPK3- and MPK6-mediated ICE1 pho- sphorylation negatively regulates ICE1 stability and freezing tolerance in Arabidopsis.Dev Cell. doi:10.1016/ j.devcel.2017.09.025. [本文引用: 1]
[39]
LiH, YeKY, ShiYT, ChengJK, ZhangXY, YangSH (2017b). BZR1 positively regulates freezing tolerance via CBF-dependent and CBF-independent pathways in Arabi- dopsis.Mol Plant 10, 545-559. DOI:10.1016/j.molp.2017.01.004PMID:28089951URL [本文引用: 3]
[40]
LiuQ, KasugaM, SakumaY, AbeH, MiuraS, Yamaguchi-ShinozakiK, ShinozakiK (1998). Two transcription factors, DREB1 and DREB2, with an EREBP/AP2 DNA binding domain separate two cellular signal transduction pathways in drought- and low-temperature-responsive ge- ne expression, respectively, in Arabidopsis.Plant Cell 10, 1391-1406. DOI:10.1105/tpc.10.8.1391PMID:9707537URLPlant growth is greatly affected by drought and low temperature. Expression of a number of genes is induced by both drought and low temperature, although these stresses are quite different. Previous experiments have established that a cis-acting element named DRE (for dehydration-responsive element) plays an important role in both dehydration- and low-temperature-induced gene expression in Arabidopsis. Two cDNA clones that encode DRE binding proteins, DREB1A and DREB2A, were isolated by using the yeast one-hybrid screening technique. The two cDNA libraries were prepared from dehydrated and cold-treated rosette plants, respectively. The deduced amino acid sequences of DREB1A and DREB2A showed no significant sequence similarity, except in the conserved DNA binding domains found in the EREBP and APETALA2 proteins that function in ethylene-responsive expression and floral morphogenesis, respectively. Both the DREB1A and DREB2A proteins specifically bound to the DRE sequence in vitro and activated the transcription of the b-glucuronidase reporter gene driven by the DRE sequence in Arabidopsis leaf protoplasts. Expression of the DREB1A gene and its two homologs was induced by low-temperature stress, whereas expression of the DREB2A gene and its single homolog was induced by dehydration. Overexpression of the DREB1A cDNA in transgenic Arabidopsis plants not only induced strong expression of the target genes under unstressed conditions but also caused dwarfed phenotypes in the transgenic plants. These transgenic plants also revealed freezing and dehydration tolerance. In contrast, overexpression of the DREB2A cDNA induced weak expression of the target genes under unstressed conditions and caused growth retardation of the transgenic plants. These results indicate that two independent families of DREB proteins, DREB1 and DREB2, function as trans-acting factors in two separate signal transduction pathways under low-temperature and dehydration conditions, respectively. [本文引用: 4]
[41]
LiuZY, JiaYX, DingYL, ShiYT, LiZ, GuoY, GongZZ, YangSH (2017). Plasma membrane CRPK1-mediated phosphorylation of 14-3-3 proteins induces their nuclear import to fine-tune CBF signaling during cold response.Mol Cell 66, 117-128. DOI:10.1016/j.molcel.2017.02.016PMID:28344081URLAbstract In plant cells, changes in fluidity of the plasma membrane may serve as the primary sensor of cold stress; however, the precise mechanism and how the cell0002transduces and fine-tunes cold signals remain elusive. Here we show that the cold-activated plasma membrane protein cold-responsive protein kinase 1 (CRPK1) phosphorylates 14-3-3 proteins. The phosphorylated 14-3-3 proteins shuttle from the cytosol to the nucleus, where they interact with and destabilize the key cold-responsive C-repeat-binding factor (CBF) proteins. Consistent with this, the crpk1 and 14-3-302020203 mutants show enhanced freezing tolerance, and transgenic plants overexpressing 14-3-30203 show reduced freezing tolerance. Further study shows that CRPK1 is essential for the nuclear translocation of 14-3-3 proteins and for 14-3-3 function in freezing tolerance. Thus, our study reveals that the CRPK1-14-3-3 module transduces the cold signal from the plasma membrane to the nucleus to modulate CBF stability, which ensures a faithfully adjusted response to cold stress of plants. Copyright 0008 2017 Elsevier Inc. All rights reserved. [本文引用: 1]
MedinaJ, BarguesM, TerolJ, Perez-AlonsoM, SalinasJ (1999). The Arabidopsis CBF gene family is composed of three genes encoding AP2 domain-containing proteins who- se expression is regulated by low temperature but not by abscisic acid or dehydration. Plant Physiol 119, 463-470. DOI:10.1104/pp.119.2.463PMID:9952441URLWe have identified two genes from Arabidopsis that show high similarity with CBF1, a gene encoding an AP2 domain-containing transcriptional activator that binds to the low-temperature-responsive element CCGAC and induces the expression of some cold-regulated genes, increasing plant freezing tolerance. These two genes, which we have named CBF2 and CBF3, also encode proteins containing AP2 DNA-binding motifs. Furthermore, like CBF1, CBF2 and CBF3 proteins also include putative nuclear-localization signals and potential acidic activation domains. The CBF2 and CBF3 genes are linked to CBF1, constituting a cluster on the bottom arm of chromosome IV. The high level of similarity among the three CBF genes, their tandem organization, and the fact that they have the same transcriptional orientation all suggest a common origin. CBF1, CBF2, and CBF3 show identical expression patterns, being induced very rapidly by low-temperature treatment. However, in contrast to most of the cold-induced plant genes characterized, they are not responsive to abscisic acid or dehydration. Taken together, all of these data suggest that CBF2 and CBF3 may function as transcriptional activators, controlling the level of low-temperature gene expression and promoting freezing tolerance through an abscisic acid-independent pathway. [本文引用: 1]
[45]
MedinaJ, CataláR, SalinasJ (2011). The CBFs: three Arabidopsis transcription factors to cold acclimate.Plant Sci 180, 3-11. DOI:10.1016/j.plantsci.2010.06.019PMID:21421341URLLow temperature is one of the adverse environmental factors that most affects plant growth and development. Temperate plants have evolved the capacity to acquire chilling and freezing tolerance after being exposed to low-nonfreezing temperatures. This adaptive response, named cold acclimation, involves many physiological and biochemical changes that mainly rely on reprogramming gene expression. Currently, the best documented genetic pathway leading to gene induction under low temperature conditions is the one mediated by the Arabidopsis C-repeat/dehydration-responsive element binding factors (CBFs), a small family of three transcriptional activators (CBF1-3) that bind to the C-repeat/dehydration-responsive element, which is present in the promoters of many cold-responsive genes, and induce transcription. The CBF genes are themselves induced by cold. Different evidences indicate that the CBF transcriptional network plays a critical role in cold acclimation in Arabidopsis. In this review, recent advances on the regulation and function of CBF factors are provided and discussed. [本文引用: 1]
MikkelsenMD, ThomashowMF (2009). A role for circadian evening elements in cold-regulated gene expression in Arabidopsis.Plant J 60, 328-339. DOI:10.1111/j.1365-313X.2009.03957.xPMID:19566593URLThe plant transcriptome is dramatically altered in response to low temperature. The cis -acting DNA regulatory elements and trans -acting factors that regulate the majority of cold-regulated genes are unknown. Previous bioinformatic analysis has indicated that the promoters of cold-induced genes are enriched in the Evening Element (EE), AAAATATCT, a DNA regulatory element that has a role in circadian-regulated gene expression. Here we tested the role of EE and EE-like (EEL) elements in cold-induced expression of two Arabidopsis genes, CONSTANS-like 1 ( COL1 ; At5g54470 ) and a gene encoding a 27-kDa protein of unknown function that we designated COLD-REGULATED GENE 27 ( COR27 ; At5g42900 ). Mutational analysis indicated that the EE/EEL elements were required for cold induction of COL1 and COR27 , and that their action was amplified through coupling with ABA response element (ABRE)-like (ABREL) motifs. An artificial promoter consisting solely of four EE motifs interspersed with three ABREL motifs was sufficient to impart cold-induced gene expression. Both COL1 and COR27 were found to be regulated by the circadian clock at warm growth temperatures and cold-induction of COR27 was gated by the clock. These results suggest that cold- and clock-regulated gene expression are integrated through regulatory proteins that bind to EE and EEL elements supported by transcription factors acting at ABREL sequences. Bioinformatic analysis indicated that the coupling of EE and EEL motifs with ABREL motifs is highly enriched in cold-induced genes and thus may constitute a DNA regulatory element pair with a significant role in configuring the low-temperature transcriptome. [本文引用: 1]
[48]
MiuraK, JinJB, LeeJ, YooCY, StirmV, MiuraT, Ash- worthEN, BressanRA, YunDJ, HasegawaPM (2007). SIZ1-mediated sumoylation of ICE1 controls CBF3/DRE- B1A expression and freezing tolerance in Arabidopsis. Plant Cell 19, 1403-1414. DOI:10.1105/tpc.106.048397PMID:17416732URLSIZ1 is a SUMO E3 ligase that facilitates conjugation of SUMO to protein substrates. siz1-2 and siz1-3 T-DNA insertion alleles that caused freezing and chilling sensitivities were complemented genetically by expressing SIZ1, indicating that the SIZ1 is a controller of low temperature adaptation in plants. Cold-induced expression of CBF/DREB1, particularly of CBF3/DREB1A, and of the regulon genes was repressed by siz1. siz1 did not affect expression of ICE1, which encodes a MYC transcription factor that is a controller of CBF3/DREB1A. A K393R substitution in ICE1 [ICE1(K393R)] blocked SIZ1-mediated sumoylation in vitro and in protoplasts identifying the K393 residue as the principal site of SUMO conjugation. SIZ1-dependent sumoylation of ICE1 in protoplasts was moderately induced by cold. Sumoylation of recombinant ICE1 reduced polyubiquitination of the protein in vitro. ICE1(K393R) expression in wild-type plants repressed cold-induced CBF3/DREB1A expression and increased freezing sensitivity. Furthermore, expression of ICE1(K393R) induced transcript accumulation of MYB15, which encodes a MYB transcription factor that is a negative regulator of CBF/DREB1. SIZ1-dependent sumoylation of ICE1 may activate and/or stabilize the protein, facilitating expression of CBF3/DREB1A and repression of MYB15, leading to low temperature tolerance. [本文引用: 2]
NakamichiN, KusanoM, FukushimaA, KitaM, ItoS, YamashinoT, SaitoK, SakakibaraH, MizunoT (2009). Transcript profiling of an Arabidopsis PSEUDO RESP- ONSE REGULATOR arrhythmic triple mutant reveals a role for the circadian clock in cold stress response. Plant Cell Physiol 50, 447-462. DOI:10.1093/pcp/pcp004PMID:19131357URLAbstract Arabidopsis PSEUDO RESPONSE REGULATOR (PRR) genes are components of the circadian clock mechanism. In order to understand the scope of genome-wide transcriptional regulation by PRR genes, a comparison survey of gene expression in wild-type Arabidopsis and a prr9-11 prr7-10 prr5-10 triple mutant (d975) using mRNA collected during late daytime was conducted using an Affymetrix ATH-1 GeneChip. The expression of 'night genes' increased and the expression of 'day genes' decreased toward the end of the diurnal light phase, but expression of these genes was essentially constant in d975. The expression levels of 'night genes' were lower, whereas the expression of 'day genes' was higher in d975 than in the wild type. Bioinformatics approaches have indicated that the set of up-regulated genes in d975 and the set of cold-responsive genes have significant overlap. We found that d975 is more tolerant to cold, high salinity and drought stresses than the wild type. In addition, dehydration-responsive element B1/C-repeat-binding factor (DREB1/CBF), which is expressed around mid-day, is more highly expressed in d975. Raffinose and L-proline accumulated at higher levels in d975 even when plants were grown under normal conditions. These results suggest that PRR9, PRR7 and PRR5 are involved in a mechanism that anticipates diurnal cold stress and which initiates a stress response by mediating cyclic expression of stress response genes, including DREB1/CBF. [本文引用: 1]
[51]
NiM, TeppermanJM, QuailPH (1998). PIF3, a phytochrome-interacting factor necessary for normal photoinduced signal transduction, is a novel basic helix-loop-helix protein.Cell 95, 657-667. DOI:10.1016/S0092-8674(00)81636-0PMID:9845368URLAbstract The mechanism by which the phytochrome (phy) photoreceptor family transduces informational light signals to photoresponsive genes is unknown. Using a yeast two-hybrid screen, we have identified a phytochrome-interacting factor, PIF3, a basic helix-loop-helix protein containing a PAS domain. PIF3 binds to wild-type C-terminal domains of both phyA and phyB, but less strongly to signaling-defective, missense mutant-containing domains. Expression of sense or antisense PIF3 sequences in transgenic Arabidopsis perturbs photoresponsiveness in a manner indicating that PIF3 functions in both phyA and phyB signaling pathways in vivo. PIF3 localized to the nucleus in transient transfection experiments, indicating a potential role in controlling gene expression. Together, the data suggest that phytochrome signaling to photoregulated genes includes a direct pathway involving physical interaction between the photoreceptor and a transcriptional regulator. [本文引用: 1]
[52]
NiWM, XuSL, González-GrandíoE, ChalkleyRJ, HuhmerAFR, BurlingameAL, WangZY, QuailPH (2017). PPKs mediate direct signal transfer from phytochrome photoreceptors to transcription factor PIF3.Nat Commun 8, 15236. DOI:10.1038/ncomms15236PMID:28492231URLAbstract Upon light-induced nuclear translocation, phytochrome (phy) sensory photoreceptors interact with, and induce rapid phosphorylation and consequent ubiquitin-mediated degradation of, transcription factors, called PIFs, thereby regulating target gene expression and plant development. Nevertheless, the biochemical mechanism of phy-induced PIF phosphorylation has remained ill-defined. Here we identify a family of nuclear protein kinases, designated Photoregulatory Protein Kinases (PPK1-4; formerly called MUT9-Like Kinases (MLKs)), that interact with PIF3 and phyB in a light-induced manner in vivo. Genetic analyses demonstrate that the PPKs are collectively necessary for the normal light-induced phosphorylation and degradation of PIF3. PPK1 directly phosphorylates PIF3 in vitro, with a phosphosite pattern that strongly mimics the light-induced pattern in vivo. These data establish that the PPKs are directly involved in catalysing the photoactivated-phy-induced phosphorylation of PIF3 in vivo, and thereby are critical components of a transcriptionally centred signalling hub that pleiotropically regulates plant growth and development in response to multiple signalling pathways. [本文引用: 1]
[53]
NiWM, XuSL, TeppermanJM, StanleyDJ, MaltbyDA, GrossJD, BurlingameAL, WangZY, QuailPH (2014). A mutually assured destruction mechanism attenuates light signaling in Arabidopsis.Science 344, 1160-1164. DOI:10.1126/science.1250778PMID:24904166URLF1000Prime Recommended Article: A mutually assured destruction mechanism attenuates light signaling in Arabidopsis. [本文引用: 2]
[54]
NosenkoT, B?ndelKB, KumpfmüllerG, StephanW (2016). Adaptation to low temperatures in the wild tomato speciesSolanum chilense. Mol Ecol 25, 2853-2869. [本文引用: 1]
[55]
NovilloF, AlonsoJM, EckerJR, SalinasJ (2004). CBF2/ DREB1C is a negative regulator of CBF1/DREB1B and CBF3/DREB1A expression and plays a central role in stress tolerance in Arabidopsis. Proc Natl Acad Sci USA 101, 3985-3990. DOI:10.1073/pnas.0303029101PMID:15004278URLAbstract CBF/DREB1 (C-repeat-binding factor/dehydration responsive element-binding factor 1) genes encode a small family of transcriptional activators that have been described as playing an important role in freezing tolerance and cold acclimation in Arabidopsis. To specify this role, we used a reverse genetic approach and identified a mutant, cbf2, in which the CBF2/DREB1C gene was disrupted. Here, we show that cbf2 plants have higher capacity to tolerate freezing than WT ones before and after cold acclimation and are more tolerant to dehydration and salt stress. All these phenotypes correlate with a stronger and more sustained expression of CBF/DREB1-regulated genes, which results from an increased expression of CBF1/DREB1B and CBF3/DREB1A in the mutant. In addition, we show that the expression of CBF1/DREB1B and CBF3/DREB1A in response to low temperature precedes that of CBF2/DREB1C. These results indicate that CBF2/DREB1C negatively regulates CBF1/DREB1B and CBF3/DREB1A, ensuring that their expression is transient and tightly controlled, which, in turn, guarantees the proper induction of downstream genes and the accurate development of Arabidopsis tolerance to freezing and related stresses. [本文引用: 2]
[56]
NovilloF, MedinaJ, SalinasJ (2007). Arabidopsis CBF1 and CBF3 have a different function than CBF2 in cold acclimation and define different gene classes in the CBF regulon.Proc Natl Acad Sci USA 104, 21002-21007. DOI:10.1073/pnas.0705639105PMID:18093929URLThe C-repeat-binding factor (CBF)/dehydration-responsive element-binding factor (DREB1) proteins constitute a small family of Arabidopsis transcriptional activators (CBF1/DREB1B, CBF2/ DREB1C, and CBF3/DREB1A) that play a prominent role in cold acclimation. A fundamental question about these factors that remains to be answered is whether they are functionally equivalent. Recently, we reported that CBF2 negatively regulates CBF1 and CBF3 expression, and that CBFs are subjected to different temporal regulation during cold acclimation, which suggested this might not be the case. In this study, we have analyzed the expression of CBF genes in different tissues of Arabidopsis, during development and in response to low temperature, and characterized RNA interference (RNAi) and antisense lines that fail to accumulate CBF1 or/and CBF3 mRNAs under cold conditions. We found that CBF1 and CBF3 are regulated in a different way than CBF2. Moreover, in contrast to CBF2, CBF1 and CBF3 are not involved in regulating other CBF genes and positively regulate cold acclimation by activating the same subset of CBF-target genes. All these results demonstrate that CBF1 and CBF3 have different functions than CBF2. We also found that the CBF regulon is composed of at least two different kind of genes, one of them requiring the simultaneous expression of both CBF1 and CBF3 to be properly induced. This indicates that CBF1 and CBF3 have a concerted additive effect to induce the whole CBF regulon and the complete development of cold acclimation. [本文引用: 5]
[57]
Ohme-TakagiM, ShinshiH (1995). Ethylene-inducible DNA binding proteins that interact with an ethylene-responsive element.Plant Cell 7, 173-182. DOI:10.2307/3869993PMID:7756828URLWe demonstrated that the GCC box, which is an 11-bp sequence (TAAGAGCCGCC) conserved in the 5 upstream region of ethylene-inducible pathogenesis-related protein genes in Nicotiana spp and in some other plants, is the sequence that is essential for ethylene responsiveness when incorporated into a heterologous promoter. Competitive gel retardation assays showed DNA binding activities to be specific to the GCC box sequence in tobacco nuclear extracts. Four different cDNAs encoding DNA binding proteins specific for the GCC box sequence were isolated, and their products were designated ethylene-responsive element binding proteins (EREBPs). The deduced amino acid sequences of EREBPs exhibited no homology with those of known DNA binding proteins or transcription factors; neither did the deduced proteins contain a basic leucine zipper or zinc finger motif. The DNA binding domain was identified within a region of 59 amino acid residues that was common to all four deduced EREBPs. Regions highly homologous to the DNA binding domain of EREBPs were found in proteins deduced from the cDNAs of various plants, suggesting that this domain is evolutionarily conserved in plants. RNA gel blot analysis revealed that accumulation of mRNAs for EREBPs was induced by ethylene, but individual EREBPs exhibited different patterns of expression. [本文引用: 1]
[58]
OkamuroJK, CasterB, VillarroelR, Van MontaguM, JofukuKD (1997). The AP2 domain of APETALA2 defines a large new family of DNA binding proteins in Arabidopsis.Proc Natl Acad Sci USA 94, 7076-7081. DOI:10.1073/pnas.94.13.7076URLAPETALA2 (AP2) plays an important role in the control of Arabidopsis flower and seed development and encodes a putative transcription factor that is distinguished by a novel DNA binding motif referred to as the AP2 domain. In this study we show that the AP2 domain containing or RAP2 (related to AP2) family of proteins is encoded by a minimum of 12 genes in Arabidopsis. The RAP2 genes encode two classes of proteins, AP2-like and EREBP-like, that are defined by the number of AP2 domains in each polypeptide as well as by two sequence motifs referred to as the YRG and RAYD elements that are located within each AP2 domain. RAP2 genes are differentially expressed in flower, leaf, inflorescence stem, and root. Moreover, the expression of at least three RAP2 genes in vegetative tissues are controlled by AP2. Thus, unlike other floral homeotic genes, AP2 is active during both reproductive and vegetative development. [本文引用: 1]
[59]
ParkS, LeeCM, DohertyCJ, GilmourSJ, KimY, Thom- ashowMF (2015). Regulation of the Arabidopsis CBF regulon by a complex low-temperature regulatory network.Plant J 82, 193-207. DOI:10.1111/tpj.12796PMID:25736223URLSummary Exposure of Arabidopsis thaliana plants to low non-freezing temperatures results in an increase in freezing tolerance that involves action of the C-repeat binding factor (CBF) regulatory pathway. CBF1 , CBF2 and CBF3 , which are rapidly induced in response to low temperature, encode closely related AP2/ERF DNA-binding proteins that recognize the C-repeat (CRT)/dehydration-responsive element (DRE) DNA regulatory element present in the promoters of CBF-regulated genes. The CBF transcription factors alter the expression of more than 100 genes, known as the CBF regulon, which contribute to an increase in freezing tolerance. In this study, we investigated the extent to which cold induction of the CBF regulon is regulated by transcription factors other than CBF1, CBF2 and CBF3, and whether freezing tolerance is dependent on a functional CBF–CRT/DRE regulatory module. To address these issues we generated transgenic lines that constitutively overexpressed a truncated version of CBF2 that had dominant negative effects on the function of the CBF–CRT/DRE regulatory module, and 11 transcription factors encoded by genes that were rapidly cold-induced in parallel with the ‘first-wave’ CBF genes, and determined the effects that overexpressing these proteins had on global gene expression and freezing tolerance. Our results indicate that cold regulation of the CBF regulon involves extensive co-regulation by other first-wave transcription factors; that the low-temperature regulatory network beyond the CBF pathway is complex and highly interconnected; and that the increase in freezing tolerance that occurs with cold acclimation is only partially dependent on the CBF–CRT/DRE regulatory module. [本文引用: 5]
[60]
QinF, SakumaY, LiJ, LiuQ, LiYQ, ShinozakiK, Yamaguchi-ShinozakiK (2004). Cloning and functional analysis of a novel DREB1/CBF transcription factor involved in cold-responsive gene expression in Zea mays L. Plant Cell Physiol 45, 1042-1052. DOI:10.1093/pcp/pch118PMID:15356330URLAbstract The transcription factors DREB1s/CBFs specifically interact with the DRE/CRT cis-acting element (core motif: G/ACCGAC) and control the expression of many stress-inducible genes in Arabidopsis. We isolated a cDNA for a DREB1/CBF homolog, ZmDREB1A in maize using a yeast one-hybrid system. The ZmDREB1A proteins specifically bound to DRE and the highly conserved valine at the 14th residue in the ERF/AP2 DNA binding domain was a key to determining the specific interaction between this protein and the DRE sequence. Expression of ZmDREB1A was induced by cold stress and slightly increased by high-salinity stress. This gene was also transiently expressed by mechanical attack. ZmDREB1A activated the transcription of the GUS reporter gene driven by DRE in rice protoplasts. Overexpression of ZmDREB1A in transgenic Arabidopsis induced overexpression of target stress-inducible genes of Arabidopsis DREB1A resulting in plants with higher tolerance to drought and freezing stresses. This indicated that ZmDREB1A has functional similarity to DREB1s/CBFs in Arabidopsis. The structure of the ERF/AP2 domain of ZmDREB1A in maize is closely related to DREB1-type ERF/AP2 domains in the monocots as compared with that in the dicots. ZmDREB1A is suggested to be potentially useful for producing transgenic plants that is tolerant to drought, high-salinity and/or cold stresses. [本文引用: 2]
[61]
RiechmannJL, MeyerowitzEM (1998). The AP2/EREBP family of plant transcription factors.Biol Chem 379, 633-646. DOI:10.1515/bchm.1998.379.6.633PMID:9687012URLAP2 (APETALA2) and EREBPs (ethylene-responsive element binding proteins) are the prototypic members of a family of transcription factors unique to plants, whose distinguishing characteristic is that they contain the so-called AP2 DNA-binding domain. AP2/ REBP genes form a large multigene family, and they play a variety of roles throughout the plant life cycle: from being key regulators of several developmental processes, like floral organ identity determination or control of leaf epidermal cell identity, to forming part of the mechanisms used by plants to respond to various types of biotic and environmental stress. The molecular and biochemical characteristics of the AP2/EREBP transcription factors and their diverse functions are reviewed here, and this multigene family is analyzed within the context of the Arabidopsis thaliana genome sequence project. [本文引用: 1]
[62]
SeoE, LeeH, JeonJ, ParkH, KimJ, NohYS, LeeI (2009). Crosstalk between cold response and flowering in Arabidopsis is mediated through the flowering-time gene SOC1 and its upstream negative regulator FLC. Plant Cell 21, 3185-3197. DOI:10.1105/tpc.108.063883PMID:19825833URLThe appropriate timing of flowering is pivotal for reproductive success in plants; thus, it is not surprising that flowering is regulated by complex genetic networks that are fine-tuned by endogenous signals and environmental cues. The Arabidopsis thaliana flowering-time gene SUPPRESSOR OF OVEREXPRESSION OF CONSTANS1 (SOC1) encodes a MADS box transcription factor and is one of the key floral activators integrating multiple floral inductive pathways, namely, long-day, vernalization, autonomous, and gibberellin-dependent pathways. To elucidate the downstream targets of SOC1, microarray analyses were performed. The analysis revealed that the soc1-2 knockout mutant has increased, and an SOC1 overexpression line has decreased, expression of cold response genes such as CBFs (for CRT/DRE binding factors) and COR (for cold regulated) genes, suggesting that SOC1 negatively regulates the expression of the cold response genes. By contrast, overexpression of cold-inducible CBFs caused late flowering through increased expression of FLOWERING LOCUS C (FLC), an upstream negative regulator of SOC1. Our results demonstrate the presence of a feedback loop between cold response and flowering-time regulation; this loop delays flowering through the increase of FLC when a cold spell is transient as in fall or early spring but suppresses the cold response when floral induction occurs through the repression of cold-inducible genes by SOC1. [本文引用: 2]
[63]
SeoPJ, ParkMJ, LimMH, KimSG, LeeM, BaldwinIT, ParkCM (2012). A self-regulatory circuit of CIRCADIAN CLOCK-ASSOCIATED1 underlies the circadian clock re- gulation of temperature responses in Arabidopsis.Plant Cell 24, 2427-2442. DOI:10.1105/tpc.112.098723URL [本文引用: 1]
[64]
ShiYT, TianSW, HouLY, HuangXZ, ZhangXY, GuoHW, YangSH (2012). Ethylene signaling negatively regulates freezing tolerance by repressing expression of CBF and type-A ARR genes in Arabidopsis. Plant Cell 24, 2578-2595. DOI:10.1105/tpc.112.098640PMID:22706288URLThe phytohormone ethylene regulates multiple aspects of plant growth and development and responses to environmental stress. However, the exact role of ethylene in freezing stress remains unclear. Here, we report that ethylene negatively regulates plant responses to freezing stress in Arabidopsis thaliana. Freezing tolerance was decreased in ethylene overproducr1 and by the application of the ethylene precursor 1-aminocyclopropane-1-carboxylic acid but increased by the addition of the ethylene biosynthesis inhibitor aminoethoxyvinyl glycine or the perception antagonist Ag + . Furthermore, ethylene-insensitive mutants, including etr1-1, ein4-1, ein2-5, ein3-1, and ein3 eil1, displayed enhanced freezing tolerance. By contrast, the constitutive ethylene response mutant ctr1-1 and EIN3-overexpressing plants exhibited reduced freezing tolerance. Genetic and biochemical analyses revealed that EIN3 negatively regulates the expression of CBFs and type-A Arabidopsis response regulator5 (ARR5), ARR7, and ARR15 by binding to specific elements in their promoters. Overexpression of these ARR genes enhanced the freezing tolerance of plants. Thus, our study demonstrates that ethylene negatively regulates cold signaling at least partially through the direct transcriptional control of cold-regulated CBFs and type-A ARR genes by EIN3. Our study also provides evidence that type-A ARRs function as key nodes to integrate ethylene and cytokinin signaling in regulation of plant responses to environmental stress. [本文引用: 3]
[65]
ShimuraY, ShiraiwaY, SuzukiI (2012). Characterization of the subdomains in the N-terminal region of histidine kinase Hik33 in the cyanobacterium Synechocystis sp. PCC 6803. Plant Cell Physiol 53, 1255-1266. DOI:10.1093/pcp/pcs068PMID:22555814URLHistidine kinase Hik33 responds to a variety of stress conditions and regulates the expression of stress-inducible genes in the cyanobacterium Synechocystis sp. PCC 6803. However, the mechanisms of response and regulation remain unknown. Generally, a histidine kinase perceives a specific signal via its N-terminal region. Hik33 has two transmembrane helices, a periplasmic loop, and HAMP and PAS domains in its N-terminal region, all of which might be involved in signal perception. To investigate the functions of these subdomains in vivo, we expressed a chimeric histidine kinase (Hik33n-SphSc) by fusing the N-terminal region of Hik33 with the C-terminal region of a sensory histidine kinase that is activated under phosphate-deficient conditions, SphS. Hik33n-SphSc responded to several stimuli that are perceived by intact Hik33 and regulated expression of the phoA gene for alkaline phosphatase, which is normally regulated under phosphate-deficient conditions by SphS. We introduced genes for modified versions of Hik33n-SphSc into Synechocystis and monitored expression of phoA under standard and stress conditions. Hik33n-SphSc lacking either the transmembrane helices or both the HAMP and PAS domains had no kinase activity, whereas Hik33n-SphSc lacking the HAMP or the PAS domain enhanced expression of phoA. Moreover, variants of Hik33n-SphSc, in which the membrane-localizing region was replaced by those of other histidine kinases, also responded to stress conditions. Thus, transmembrane helices, regardless of sequence, appear to be essential for the function of Hik33, while the HAMP and PAS domains play important roles in regulating kinase activity in vivo. [本文引用: 1]
[66]
StockingerEJ, GilmourSJ, ThomashowMF (1997). Ara- bidopsis thaliana CBF1 encodes an AP2 domaincon- taining transcriptional activator that binds to the C-repeat/ DRE, a cis-acting DNA regulatory element that stimulates transcription in response to low temperature and water deficit. Proc Natl Acad Sci USA 94, 1035-1040. [本文引用: 1]
[67]
YinYH, VafeadosD, TaoY, YoshidaS, AsamiT, ChoryJ (2005). A new class of transcription factors mediates br- assinosteroid-regulated gene expression in Arabidopsis.Cell 120, 249-259. DOI:10.1016/j.cell.2004.11.044PMID:15680330URLAbstract Brassinosteroids (BRs) signal through a plasma membrane-localized receptor kinase to regulate plant growth and development. We showed previously that a novel protein, BES1, accumulates in the nucleus in response to BRs, where it plays a role in BR-regulated gene expression; however, the mechanism by which BES1 regulates gene expression is unknown. In this study, we dissect BES1 subdomains and establish that BES1 is a transcription factor that binds to and activates BR target gene promoters both in vitro and in vivo. BES1 interacts with a basic helix-loop-helix protein, BIM1, to synergistically bind to E box (CANNTG) sequences present in many BR-induced promoters. Loss-of-function and gain-of-function mutants of BIM1 and its close family members display BR response phenotypes. Thus, BES1 defines a new class of plant-specific transcription factors that cooperate with transcription factors such as BIM1 to regulate BR-induced genes. [本文引用: 1]
[68]
ZabulonG, RichaudC, Guidi-RontaniC, ThomasJC (2007). NblA gene expression in Synechocystis PCC 6803 strains lacking DspA (Hik33) and a NblR-like protein. Curr Microbiol 54, 36-41. [本文引用: 1]
[69]
ZhaoCZ, WangPC, SiT, HsuCC, WangL, ZayedO, YuZP, ZhuYF, DongJ, TaoWA, ZhuJK (2017). MAP kinase cascades regulate the cold response by modulating ICE1 protein stability.Dev Cell. doi:10.1016/j.devcel. 2017.09.024 DOI:10.1016/j.devcel.2017.09.024PMID:29056551URLAbstract Graphical Abstract Highlights d The MKK4/5-MPK3/6 cascade negatively regulates freezing tolerance d The MEKK1-MKK2-MPK4 cascade positively regulates freezing tolerance d MPK3/6-mediated phosphorylation of ICE1 promotes ICE1 degradation d CRLK1 and CRLK2 suppress the cold activation of MPK3/6 Correspondence jkzhu@sibs.ac.cn In Brief ICE1 is a central regulator of the plant cold response, and its levels are tightly controlled. Zhao et al. show that cold-activated MPK3 and MPK6 phosphorylate ICE1 and promote its degradation, thus negatively regulating the cold response, whereas MPK4 positively regulates the cold response by constitutively suppressing MPK3 and MPK6 activity. SUMMARY Mitogen-activated protein kinase cascades are important signaling modules that convert environmental stimuli into cellular responses. We show that MPK3, MPK4, and MPK6 are rapidly activated after cold treatment. The mpk3 and mpk6 mutants display increased expression of CBF genes and enhanced freezing tolerance, whereas constitutive activation of the MKK4/5-MPK3/6 cascade in plants causes reduced expression of CBF genes and hypersensitiv-ity to freezing, suggesting that the MKK4/5-MPK3/6 cascade negatively regulates the cold response. MPK3 and MPK6 can phosphorylate ICE1, a basic-helix-loop-helix transcription factor that regulates the expression of CBF genes, and the phosphoryla-tion promotes the degradation of ICE1. Interestingly, the MEKK1-MKK2-MPK4 pathway constitutively suppresses MPK3 and MPK6 activities and has a positive role in the cold response. Furthermore, the MAPKKK YDA and two calcium/calmodulin-regulated receptor-like kinases, CRLK1 and CRLK2, negatively modulate the cold activation of MPK3/6. Our results uncover important roles of MAPK cascades in the regulation of plant cold response. [本文引用: 1]
[70]
ZhaoCZ, ZhangZJ, XieSJ, SiT, LiYY, ZhuJK (2016). Mutational evidence for the critical role of CBF transcription factors in cold acclimation in Arabidopsis.Plant Phy- siol 171, 2744-2759. DOI:10.1104/pp.16.00533PMID:27252305URLThe three tandemly arranged CBF genes, CBF1, CBF2 and CBF3, are involved in cold acclimation. Due to the lack of stable loss-of-function Arabidopsis mutants deficient in all three CBF genes, it is still unclear whether the CBF genes are essential for freezing tolerance and whether they may have other functions besides cold acclimation. In this study, we used the CRISPR/Cas9 system to generate cbf single, double and triple mutants. Compared to the wild type, the cbf triple mutants are extremely sensitive to freezing after cold acclimation, demonstrating that the three CBF genes are essential for cold acclimation. Our results show that the three CBF genes also contribute to basal freezing tolerance. Unexpectedly, we found that the cbf triple mutants are defective in seedling development and salt stress tolerance. Transcript profiling revealed that the CBF genes regulate 414 cold-responsive (COR) genes, of which 346 are CBF-activated genes, and 68 are CBF-repressed genes. The analysis suggested that CBF proteins are extensively involved in the regulation of carbohydrate and lipid metabolism, cell wall modification, and gene transcription. Interestingly, like the triple mutants, cbf2 cbf3 double mutants are more sensitive to freezing after cold acclimation compared to the wild type, but cbf1 cbf3 double mutants are more resistant, suggesting that CBF2 is more important than CBF1 and CBF3 in cold acclimation-dependent freezing tolerance. Our results not only demonstrate that the three CBF genes together are required for cold acclimation and freezing tolerance, but also reveal that they are important for salt tolerance and seedling development. [本文引用: 7]
3 2008
... 尽管CBF在冷诱导基因调控中发挥重要作用, 但植物中还存在其它转录因子调控COR基因.Thom- show实验室通过对CBF过表达株系的RNA-seq数据分析, 发现CBF2与转录因子HSFC1、ZAT12、ZF、ZAT10及CZF1共同调控下游COR基因(当然也有像GOL3这样完全依赖CBF的冷响应基因) (Park et al., 2015), 同时多项研究表明植物中也存在不依赖于CBF的冷响应基因(Achard et al., 2008; Park et al., 2015; Jia et al., 2016; Zhao et al., 2016), 表明植物中的冷响应基因调控网络非常复杂且具有内在联系, 这其中的更多调控机制还有待进一步研究. ... ... 一系列研究表明CBF参与植物的生长发育过程.过表达CBF导致植株矮小, 且与野生型相比, 开花时间明显延迟(Gilmour et al., 2004; Park et al., 2015).对突变体的研究表明, cbf1/cbf2/cbf3三突变体种子萌发率与野生型相比降低一半, 根生长速率略慢于野生型, 植株的莲座叶数目减少, 形态偏小, 生物量也低于野生型(Zhao et al., 2016).这些结果说明, CBF是植物生长发育过程中的关键因素.Jia等(2016)研究表明, 低温下无论是土中还是培养皿上生长的cbf1/cbf2/cbf3三突变体植株均明显大于野生型, 说明CBF影响了低温胁迫下植物的生长发育(Jia et al., 2016).有趣的是, 外源施加影响植物细胞伸长的植物激素赤霉素(gibberellin acid, GA)可以回复CBF1过表达植株的生长发育矮小表型(Achard et al., 2008).过表达CBF1可以激活植物体内GA2ox基因的表达, 使植物体内活性形式的GA含量下降, 造成GA信号途径的负调节因子DELLA蛋白在植物体内高水平积累, 从而导致植株生长受到抑制.DELLA基因突变可以部分回复CBF1过表达植株的矮小表型, 这些结果暗示, CBF在生长发育中的作用需要GA及DELLA蛋白的参与(Achard et al., 2008).不仅CBF影响植物的生长发育, CBF的上游调控因子如ICE1、ICE2、EIN3、BZR1、PIF3/4/7和SOC1等也全部参与调控植物的生长发育, 突变体均表现出各种生长发育表型, 这暗示着植物产生对低温胁迫的抗性很可能需要以牺牲生长发育作为代价.最新研究表明, 植物面对低温胁迫时, 会自主启动细胞死亡机制, 优先杀死未成熟的小柱干细胞, 使根部静止中心维持高浓度生长素, 有利于干细胞巢(stem cell niche)抵抗低温胁迫(Hong et al., 2017).但这一机制具有特异性, CBF是否参与这一过程目前仍有待研究.植物面对低温或者其它胁迫可能要做出选择: 是继续正常生长发育从而造成对胁迫的敏感, 还是牺牲生长发育, 利用更多能量产生抵抗物质来对抗逆境? CBF可能参与低温胁迫及生长发育调控, 寻找到一种平衡植物抗冻及生长发育受损的调控机制可能是后续需要认真研究的科学问题. ... ... 过表达植株的矮小表型, 这些结果暗示, CBF在生长发育中的作用需要GA及DELLA蛋白的参与(Achard et al., 2008).不仅CBF影响植物的生长发育, CBF的上游调控因子如ICE1、ICE2、EIN3、BZR1、PIF3/4/7和SOC1等也全部参与调控植物的生长发育, 突变体均表现出各种生长发育表型, 这暗示着植物产生对低温胁迫的抗性很可能需要以牺牲生长发育作为代价.最新研究表明, 植物面对低温胁迫时, 会自主启动细胞死亡机制, 优先杀死未成熟的小柱干细胞, 使根部静止中心维持高浓度生长素, 有利于干细胞巢(stem cell niche)抵抗低温胁迫(Hong et al., 2017).但这一机制具有特异性, CBF是否参与这一过程目前仍有待研究.植物面对低温或者其它胁迫可能要做出选择: 是继续正常生长发育从而造成对胁迫的敏感, 还是牺牲生长发育, 利用更多能量产生抵抗物质来对抗逆境? CBF可能参与低温胁迫及生长发育调控, 寻找到一种平衡植物抗冻及生长发育受损的调控机制可能是后续需要认真研究的科学问题. ...
2 2006
... 除了各种正调控因子调控CBF基因的转录水平, 许多负调节因子也参与对CBF基因的精细调控.MYB15是第1个被发现的CBF基因负调节因子.它编码1个R2R3类MYB转录因子, 结合在CBF3的MYB结合位点.进一步研究发现, MYB15与ICE1相互作用, 共同调控CBF3的表达.突变体中CBF3表达量升高, 植株表现出抗冻表型, 同时低温可以诱导MYB15的表达水平, 说明对CBF3的表达调控可能存在负反馈调节机制(Agarwal et al., 2006).近期的研究结果表明, MYB15的第168位Ser可以被MPK6磷酸化, 从而降低MYB15与CBF3启动子的结合能力, 将该Ser突变成Ala可以增强MYB15对CBF3的抑制.同时过量表达磷酸化位点失活形式的MYB15可使植株体内的CBF3表达水平显著降低, 其抗冻性强于MYB15过表达植株.以上结果表明, MYB15对CBF3的转录调节受到MPK6的磷酸化调控(Kim et al., 2017).目前发现MYB15可以与ICE1相互作用并调控其转录活性(Agarwal et al., 2006), 暗示转录调节子之间存在复杂的调控机制. ... ... ).目前发现MYB15可以与ICE1相互作用并调控其转录活性(Agarwal et al., 2006), 暗示转录调节子之间存在复杂的调控机制. ...
1 1994
... 在拟南芥(Arabidopsis thaliana)基因组中存在3个CBF基因, 属于一类转录因子家族CBF/DREB1 (de- hydration-responsive element-binding factors 1)基因.CBF家族成员串联排列在拟南芥第4条染色体上, 分别命名为CBF1 (DREB1B)、CBF2 (DREB1C)和CBF3 (DREB1A) (Gilmour et al., 1998; Liu et al., 1998).1997-1998年, Thomashow等利用酵母单杂交等技术相继鉴定到了CBF1-CBF3 (Stockinger et al., 1997; Gilmour et al., 1998; Liu et al., 1998), 它们可以与一段保守的CRT/DRE (C-repeat/dehydration response element)调控元件CCGAC结合(Baker et al., 1994), 该元件多出现在冷诱导COR (Cold- regulated)基因的启动子区域(Medina et al., 2011).氨基酸序列比对结果显示, CBF1-CBF3三者之间具有很高的相似性(>85%), 暗示它们可能起源于同一个基因(Gilmour et al., 1998; Medina et al., 1999).过量表达CBF1、CBF2及CBF3均能大幅提高植株的抗冻性, 并显著诱导植株体内COR基因的表达(Liu et al., 1998). ...
1 2008
... 植物的开花过程也受到低温调控, 低温可抑制开花而高温则促进开花(Blázquez et al., 2003).开花途径重要的调节因子SOC1 (suppressor of overexpression of constans 1)编码1个MADS类转录因子, 研究表明SOC1可以直接结合CBF启动子的CArG元件, 负调节CBF基因的表达(Seo et al., 2009).与此对应, soc1突变体也表现出明显的抗冻性, 说明SOC1是开花途径与低温信号途径相互作用的节点(Seo et al., 2009).自2000年以来, 不断有研究表明, CBF及其下游冷响应基因的表达存在节律现象(Har- mer et al., 2000; Bieniawska et al., 2008; Espinoza et al., 2008; Mikkelsen and Thomashow, 2009), 其基因表达在黎明后8小时达到峰值, 并在黎明后20小时达到低谷.多项研究表明, 节律可以同时正向及负向调控CBF基因的转录水平.节律中心调控因子包括MYB类转录因子CCA1 (circadian clock associated 1)与LHY (late elongated hypocotyl)以及PRR (pseudoresponse regulator)蛋白TOC1, 它们相互调控彼此的基因表达, 从而形成反馈环机制.三突变体prr5/prr7/prr9中CBF基因组成型高水平表达, 并表现出明显的抗冻表型, 暗示PRRs参与抑制CBF基因表达(Nakamichi et al., 2009, 2012).2011年, Thom- ashow实验室发现拟南芥中央振荡器因子CCA1及LHY可以正调控CBF的表达.CCA1及LHY均编码MYB类转录因子, 它们通过结合CBF1-CBF3基因启动子上的EE及CBS结合位点, 直接调控CBF基因表达.cca1/lhy双突变体中CBF基因表达水平大幅下调, 并且CBF基因表达的节律性也有所减弱(Dong et al., 2011).CBF下游调控基因COR15A、COR47及COR78表达水平也显著下调.双突变体在冷驯化前后均表现出敏感表型, 说明节律调控因子CCA1及LHY通过直接调控CBF的表达, 参与低温信号途径(Dong et al., 2011).进一步研究发现, CCA1的2个转录本CCA1α及CCA1β均参与低温信号途径.低温抑制CCA1β的表达, 而CCA1β通过与CCA1α相互作用, 抑制CCA1α的表达(Seo et al., 2012). ...
1 2003
... 植物的开花过程也受到低温调控, 低温可抑制开花而高温则促进开花(Blázquez et al., 2003).开花途径重要的调节因子SOC1 (suppressor of overexpression of constans 1)编码1个MADS类转录因子, 研究表明SOC1可以直接结合CBF启动子的CArG元件, 负调节CBF基因的表达(Seo et al., 2009).与此对应, soc1突变体也表现出明显的抗冻性, 说明SOC1是开花途径与低温信号途径相互作用的节点(Seo et al., 2009).自2000年以来, 不断有研究表明, CBF及其下游冷响应基因的表达存在节律现象(Har- mer et al., 2000; Bieniawska et al., 2008; Espinoza et al., 2008; Mikkelsen and Thomashow, 2009), 其基因表达在黎明后8小时达到峰值, 并在黎明后20小时达到低谷.多项研究表明, 节律可以同时正向及负向调控CBF基因的转录水平.节律中心调控因子包括MYB类转录因子CCA1 (circadian clock associated 1)与LHY (late elongated hypocotyl)以及PRR (pseudoresponse regulator)蛋白TOC1, 它们相互调控彼此的基因表达, 从而形成反馈环机制.三突变体prr5/prr7/prr9中CBF基因组成型高水平表达, 并表现出明显的抗冻表型, 暗示PRRs参与抑制CBF基因表达(Nakamichi et al., 2009, 2012).2011年, Thom- ashow实验室发现拟南芥中央振荡器因子CCA1及LHY可以正调控CBF的表达.CCA1及LHY均编码MYB类转录因子, 它们通过结合CBF1-CBF3基因启动子上的EE及CBS结合位点, 直接调控CBF基因表达.cca1/lhy双突变体中CBF基因表达水平大幅下调, 并且CBF基因表达的节律性也有所减弱(Dong et al., 2011).CBF下游调控基因COR15A、COR47及COR78表达水平也显著下调.双突变体在冷驯化前后均表现出敏感表型, 说明节律调控因子CCA1及LHY通过直接调控CBF的表达, 参与低温信号途径(Dong et al., 2011).进一步研究发现, CCA1的2个转录本CCA1α及CCA1β均参与低温信号途径.低温抑制CCA1β的表达, 而CCA1β通过与CCA1α相互作用, 抑制CCA1α的表达(Seo et al., 2012). ...
2 2010
... CBF属于AP2/ERF (APETALA 2/ethylene-res- ponsive)转录因子家族成员的一个亚家族.该家族在拟南芥中有145个成员, 均含有1个或多个保守的AP2/ ERF结构域(Ohme-Takagi and Shinshi, 1995).研究表明该结构域是转录因子中的DNA结合区域(Okam- uro et al., 1997; Riechmann and Meyerowitz, 1998).不同于AP2家族的其它亚家族, CBF家族成员只有1个AP2结构域, 并且在AP2的上下游各有一段保守的氨基酸序列PKKP/PKKPAGR (RAGRxxKFx ETRHP)和DSAWR (Jaglo et al., 2001; Canella et al., 2010).将PKKPAGR突变可以抑制CBF1与其下游基因COR- 15a启动子CRT/DRE的结合能力, 从而削弱CBF1对COR15a基因的冷诱导水平调控, 说明该基序对CBF行使其转录因子功能是必需的(Canella et al., 2010). ... ... 基因的冷诱导水平调控, 说明该基序对CBF行使其转录因子功能是必需的(Canella et al., 2010). ...
4 2003
... 第1个被鉴定的同时也是研究得最深入的CBF冷响应正调节因子是bHLH类转录因子ICE1 (inducer of CBF expression 1) (Chinnusamy et al., 2003).2003年, 朱健康实验室利用EMS诱变含有ProCBF3:LUC的拟南芥转基因植株, 获得了ice1突变体, 并成功克隆到ICE1基因(Chinnusamy et al., 2003).ICE1编码1个MYC类bHLH家族转录因子, 与野生型相比, ice1突变体植株矮小, 生长发育缓慢, 体内CBF3基因的冷诱导情况被严重抑制, 且抗冻性大幅降低.这些结果表明, ICE1是低温信号途径中的正调控因子(Chinnusamy et al., 2003; Lee et al., 2005).有趣的是, ICE1特异性调节CBF3基因表达, ice1突变体中CBF1及CBF2基因的冷诱导表达下调十分微弱且后期没有影响, 说明ICE1的调节具有特异性.这可能与CBF基因启动子上的MYC结合位点的数目有关(CBF3启动子有5个结合位点, CBF1及CBF2启动子各有1个结合位点).ICE1特异性结合在CBF3启动子的MYC结合位点CANNTG (Meshi and Iwabuchi, 1995), 正调控CBF3基因表达.过表达ICE1可以明显增强植株的抗冻能力(Chinnusamy et al., 2003).最近在水稻、玉米及番茄的研究中发现, ICE1均可以正调控植物的耐寒性, 将这些物种中的ICE1蛋白在拟南芥中过表达均可增强植株的抗冻性, 说明ICE1在低温信号途径中的功能非常保守(Nosenko et al., 2016; Deng et al., 2017; Lu et al., 2017).ICE2作为ICE1的同源基因, 也参与调控植物的抗冻性.过表达ICE2可以显著提高植物的抗冻性, 并且植物体内的CBF1基因也被诱导表达, 暗示ICE2作用在CBF1的上游(Fursova et al., 2009). ... ... 基因(Chinnusamy et al., 2003).ICE1编码1个MYC类bHLH家族转录因子, 与野生型相比, ice1突变体植株矮小, 生长发育缓慢, 体内CBF3基因的冷诱导情况被严重抑制, 且抗冻性大幅降低.这些结果表明, ICE1是低温信号途径中的正调控因子(Chinnusamy et al., 2003; Lee et al., 2005).有趣的是, ICE1特异性调节CBF3基因表达, ice1突变体中CBF1及CBF2基因的冷诱导表达下调十分微弱且后期没有影响, 说明ICE1的调节具有特异性.这可能与CBF基因启动子上的MYC结合位点的数目有关(CBF3启动子有5个结合位点, CBF1及CBF2启动子各有1个结合位点).ICE1特异性结合在CBF3启动子的MYC结合位点CANNTG (Meshi and Iwabuchi, 1995), 正调控CBF3基因表达.过表达ICE1可以明显增强植株的抗冻能力(Chinnusamy et al., 2003).最近在水稻、玉米及番茄的研究中发现, ICE1均可以正调控植物的耐寒性, 将这些物种中的ICE1蛋白在拟南芥中过表达均可增强植株的抗冻性, 说明ICE1在低温信号途径中的功能非常保守(Nosenko et al., 2016; Deng et al., 2017; Lu et al., 2017).ICE2作为ICE1的同源基因, 也参与调控植物的抗冻性.过表达ICE2可以显著提高植物的抗冻性, 并且植物体内的CBF1基因也被诱导表达, 暗示ICE2作用在CBF1的上游(Fursova et al., 2009). ... ... 基因的冷诱导情况被严重抑制, 且抗冻性大幅降低.这些结果表明, ICE1是低温信号途径中的正调控因子(Chinnusamy et al., 2003; Lee et al., 2005).有趣的是, ICE1特异性调节CBF3基因表达, ice1突变体中CBF1及CBF2基因的冷诱导表达下调十分微弱且后期没有影响, 说明ICE1的调节具有特异性.这可能与CBF基因启动子上的MYC结合位点的数目有关(CBF3启动子有5个结合位点, CBF1及CBF2启动子各有1个结合位点).ICE1特异性结合在CBF3启动子的MYC结合位点CANNTG (Meshi and Iwabuchi, 1995), 正调控CBF3基因表达.过表达ICE1可以明显增强植株的抗冻能力(Chinnusamy et al., 2003).最近在水稻、玉米及番茄的研究中发现, ICE1均可以正调控植物的耐寒性, 将这些物种中的ICE1蛋白在拟南芥中过表达均可增强植株的抗冻性, 说明ICE1在低温信号途径中的功能非常保守(Nosenko et al., 2016; Deng et al., 2017; Lu et al., 2017).ICE2作为ICE1的同源基因, 也参与调控植物的抗冻性.过表达ICE2可以显著提高植物的抗冻性, 并且植物体内的CBF1基因也被诱导表达, 暗示ICE2作用在CBF1的上游(Fursova et al., 2009). ... ... 可以明显增强植株的抗冻能力(Chinnusamy et al., 2003).最近在水稻、玉米及番茄的研究中发现, ICE1均可以正调控植物的耐寒性, 将这些物种中的ICE1蛋白在拟南芥中过表达均可增强植株的抗冻性, 说明ICE1在低温信号途径中的功能非常保守(Nosenko et al., 2016; Deng et al., 2017; Lu et al., 2017).ICE2作为ICE1的同源基因, 也参与调控植物的抗冻性.过表达ICE2可以显著提高植物的抗冻性, 并且植物体内的CBF1基因也被诱导表达, 暗示ICE2作用在CBF1的上游(Fursova et al., 2009). ...
1 2017
... 第1个被鉴定的同时也是研究得最深入的CBF冷响应正调节因子是bHLH类转录因子ICE1 (inducer of CBF expression 1) (Chinnusamy et al., 2003).2003年, 朱健康实验室利用EMS诱变含有ProCBF3:LUC的拟南芥转基因植株, 获得了ice1突变体, 并成功克隆到ICE1基因(Chinnusamy et al., 2003).ICE1编码1个MYC类bHLH家族转录因子, 与野生型相比, ice1突变体植株矮小, 生长发育缓慢, 体内CBF3基因的冷诱导情况被严重抑制, 且抗冻性大幅降低.这些结果表明, ICE1是低温信号途径中的正调控因子(Chinnusamy et al., 2003; Lee et al., 2005).有趣的是, ICE1特异性调节CBF3基因表达, ice1突变体中CBF1及CBF2基因的冷诱导表达下调十分微弱且后期没有影响, 说明ICE1的调节具有特异性.这可能与CBF基因启动子上的MYC结合位点的数目有关(CBF3启动子有5个结合位点, CBF1及CBF2启动子各有1个结合位点).ICE1特异性结合在CBF3启动子的MYC结合位点CANNTG (Meshi and Iwabuchi, 1995), 正调控CBF3基因表达.过表达ICE1可以明显增强植株的抗冻能力(Chinnusamy et al., 2003).最近在水稻、玉米及番茄的研究中发现, ICE1均可以正调控植物的耐寒性, 将这些物种中的ICE1蛋白在拟南芥中过表达均可增强植株的抗冻性, 说明ICE1在低温信号途径中的功能非常保守(Nosenko et al., 2016; Deng et al., 2017; Lu et al., 2017).ICE2作为ICE1的同源基因, 也参与调控植物的抗冻性.过表达ICE2可以显著提高植物的抗冻性, 并且植物体内的CBF1基因也被诱导表达, 暗示ICE2作用在CBF1的上游(Fursova et al., 2009). ...
2 2015
... ICE1作为重要的CBF调节因子, 自身也被很多组分精细调控.目前已知的对ICE1的翻译后修饰包括HOS1 (high osmotic expression 1)介导的泛素化、SIZ1 (SAP and Miz 1)介导的SUMO化以及OST1 (open stomata 1)介导的磷酸化等, 这些修饰通过调节ICE1的蛋白水平或转录水平参与调控冷信号途径.同时一些转录抑制子(MYB15和JAZ)还可以与ICE1相互作用, 从而调节它的转录活性.HOS1与ICE1相互作用, 泛素化ICE1蛋白, 使其通过26S蛋白酶体途径进行降解(Dong et al., 2006).HOS1过表达植株中CBF3基因表达水平下调, 植株表现出冻敏感表型(Dong et al., 2006).ICE1还受到另一种E3蛋白SIZ1的SUMO化调控(Miura et al., 2007).SIZ1使ICE1蛋白SUMO化, 并减弱ICE1的泛素化, 从而维持ICE1蛋白的稳定性.siz1突变体中CBF3基因表达水平下调, 植株呈冻敏感表型(Miura et al., 2007).JA信号途径的负调节因子JAZ1 (jasmonate ZIM-domain)与JAZ4通过与ICE1蛋白具有bHLH结构域的C端相互作用, 抑制ICE1的转录活性, 从而参与对低温信号途径的调控(Hu et al., 2013).与之相对应, 过表达JAZ1及JAZ4的转基因植株, 以及JA合成途径及信号途径中一些组分的突变体均表现出低温敏感的表型(Hu et al., 2013).本实验室研究表明, 低温可以激活ABA信号途径中的重要激酶OST1, 使其磷酸化ICE1第278位Ser, 正调控ICE1蛋白的稳定性及转录活性, 从而促进下游CBF基因的表达(Ding et al., 2015).OST1对ICE1的磷酸化作用还可以抑制其与HOS1的互作, 从而抑制HOS1对ICE1的降解.以上结果说明OST1作为蛋白激酶, 在低温信号途径中起关键正调控作用(Ding et al., 2015).除此之外, 本实验室及朱健康研究组同时发现, 低温可以激活丝裂原活化蛋白激酶MPK3及MPK6, 它们通过磷酸化ICE1 (磷酸化位点与OST1对ICE1的磷酸化位点不同), 抑制ICE1蛋白的稳定性和转录活性, 从而负调控CBF基因表达及植物的抗冻性(Li et al., 2017a; Zhao et al., 2017).这些结果说明, ICE1作为重要的低温信号途径的转录因子, 被多种调节子不同程度地调控, 从而使植物更好地应对低温胁迫, 做出精细的应答反应. ... ... ).OST1对ICE1的磷酸化作用还可以抑制其与HOS1的互作, 从而抑制HOS1对ICE1的降解.以上结果说明OST1作为蛋白激酶, 在低温信号途径中起关键正调控作用(Ding et al., 2015).除此之外, 本实验室及朱健康研究组同时发现, 低温可以激活丝裂原活化蛋白激酶MPK3及MPK6, 它们通过磷酸化ICE1 (磷酸化位点与OST1对ICE1的磷酸化位点不同), 抑制ICE1蛋白的稳定性和转录活性, 从而负调控CBF基因表达及植物的抗冻性(Li et al., 2017a; Zhao et al., 2017).这些结果说明, ICE1作为重要的低温信号途径的转录因子, 被多种调节子不同程度地调控, 从而使植物更好地应对低温胁迫, 做出精细的应答反应. ...
2 2009
... 除了ICE家族转录因子, 钙信号通路的重要组分CAMTA3 (calmodulin-binding transcription activator 3)也被发现参与CBF基因表达调控.Thomashow实验室通过鉴定冷诱导相关的顺式作用元件, 发现CBF2基因的启动子含有7个保守的CM (conserved motif)基序参与CBF2转录活性调控.进一步研究发现钙信号途径的转录因子CAMTA3可以通过与CM2位点结合, 正调控CBF1与CBF2的表达(Doherty et al., 2009).CAMTA1-3的不同组合双突变体在冷驯化前后均表现出冻敏感表型, 且驯化后的表型更明显.同时突变体中CBF1、CBF2、CBF3及下游冷相关基因的表达均有不同程度的下调, 说明这类转录因子共同参与CBF介导的植物抗冻性调控(Doherty et al., 2009; Kim et al., 2013).最近, Yamaguchi-Shinozaki研究组利用不同的camta突变体, 系统研究了CAM- TA蛋白对CBF的转录调控, 发现在迅速降温(10分钟之内从22°C降到4°C)和缓慢降温(60分钟内从22°C降到4°C)这2种过程中可能存在不同的调控机制(Kid- okoro et al., 2017).CAMTA3和CAMTA5在迅速降温过程中调控CBF的表达, 但在缓慢降温过程中则不起作用, 暗示这2种不同的降温过程可能存在不同的低温调控机制(Kidokoro et al., 2017). ... ... 及下游冷相关基因的表达均有不同程度的下调, 说明这类转录因子共同参与CBF介导的植物抗冻性调控(Doherty et al., 2009; Kim et al., 2013).最近, Yamaguchi-Shinozaki研究组利用不同的camta突变体, 系统研究了CAM- TA蛋白对CBF的转录调控, 发现在迅速降温(10分钟之内从22°C降到4°C)和缓慢降温(60分钟内从22°C降到4°C)这2种过程中可能存在不同的调控机制(Kid- okoro et al., 2017).CAMTA3和CAMTA5在迅速降温过程中调控CBF的表达, 但在缓慢降温过程中则不起作用, 暗示这2种不同的降温过程可能存在不同的低温调控机制(Kidokoro et al., 2017). ...
2 2006
... ICE1作为重要的CBF调节因子, 自身也被很多组分精细调控.目前已知的对ICE1的翻译后修饰包括HOS1 (high osmotic expression 1)介导的泛素化、SIZ1 (SAP and Miz 1)介导的SUMO化以及OST1 (open stomata 1)介导的磷酸化等, 这些修饰通过调节ICE1的蛋白水平或转录水平参与调控冷信号途径.同时一些转录抑制子(MYB15和JAZ)还可以与ICE1相互作用, 从而调节它的转录活性.HOS1与ICE1相互作用, 泛素化ICE1蛋白, 使其通过26S蛋白酶体途径进行降解(Dong et al., 2006).HOS1过表达植株中CBF3基因表达水平下调, 植株表现出冻敏感表型(Dong et al., 2006).ICE1还受到另一种E3蛋白SIZ1的SUMO化调控(Miura et al., 2007).SIZ1使ICE1蛋白SUMO化, 并减弱ICE1的泛素化, 从而维持ICE1蛋白的稳定性.siz1突变体中CBF3基因表达水平下调, 植株呈冻敏感表型(Miura et al., 2007).JA信号途径的负调节因子JAZ1 (jasmonate ZIM-domain)与JAZ4通过与ICE1蛋白具有bHLH结构域的C端相互作用, 抑制ICE1的转录活性, 从而参与对低温信号途径的调控(Hu et al., 2013).与之相对应, 过表达JAZ1及JAZ4的转基因植株, 以及JA合成途径及信号途径中一些组分的突变体均表现出低温敏感的表型(Hu et al., 2013).本实验室研究表明, 低温可以激活ABA信号途径中的重要激酶OST1, 使其磷酸化ICE1第278位Ser, 正调控ICE1蛋白的稳定性及转录活性, 从而促进下游CBF基因的表达(Ding et al., 2015).OST1对ICE1的磷酸化作用还可以抑制其与HOS1的互作, 从而抑制HOS1对ICE1的降解.以上结果说明OST1作为蛋白激酶, 在低温信号途径中起关键正调控作用(Ding et al., 2015).除此之外, 本实验室及朱健康研究组同时发现, 低温可以激活丝裂原活化蛋白激酶MPK3及MPK6, 它们通过磷酸化ICE1 (磷酸化位点与OST1对ICE1的磷酸化位点不同), 抑制ICE1蛋白的稳定性和转录活性, 从而负调控CBF基因表达及植物的抗冻性(Li et al., 2017a; Zhao et al., 2017).这些结果说明, ICE1作为重要的低温信号途径的转录因子, 被多种调节子不同程度地调控, 从而使植物更好地应对低温胁迫, 做出精细的应答反应. ... ... 基因表达水平下调, 植株表现出冻敏感表型(Dong et al., 2006).ICE1还受到另一种E3蛋白SIZ1的SUMO化调控(Miura et al., 2007).SIZ1使ICE1蛋白SUMO化, 并减弱ICE1的泛素化, 从而维持ICE1蛋白的稳定性.siz1突变体中CBF3基因表达水平下调, 植株呈冻敏感表型(Miura et al., 2007).JA信号途径的负调节因子JAZ1 (jasmonate ZIM-domain)与JAZ4通过与ICE1蛋白具有bHLH结构域的C端相互作用, 抑制ICE1的转录活性, 从而参与对低温信号途径的调控(Hu et al., 2013).与之相对应, 过表达JAZ1及JAZ4的转基因植株, 以及JA合成途径及信号途径中一些组分的突变体均表现出低温敏感的表型(Hu et al., 2013).本实验室研究表明, 低温可以激活ABA信号途径中的重要激酶OST1, 使其磷酸化ICE1第278位Ser, 正调控ICE1蛋白的稳定性及转录活性, 从而促进下游CBF基因的表达(Ding et al., 2015).OST1对ICE1的磷酸化作用还可以抑制其与HOS1的互作, 从而抑制HOS1对ICE1的降解.以上结果说明OST1作为蛋白激酶, 在低温信号途径中起关键正调控作用(Ding et al., 2015).除此之外, 本实验室及朱健康研究组同时发现, 低温可以激活丝裂原活化蛋白激酶MPK3及MPK6, 它们通过磷酸化ICE1 (磷酸化位点与OST1对ICE1的磷酸化位点不同), 抑制ICE1蛋白的稳定性和转录活性, 从而负调控CBF基因表达及植物的抗冻性(Li et al., 2017a; Zhao et al., 2017).这些结果说明, ICE1作为重要的低温信号途径的转录因子, 被多种调节子不同程度地调控, 从而使植物更好地应对低温胁迫, 做出精细的应答反应. ...
2 2011
... 植物的开花过程也受到低温调控, 低温可抑制开花而高温则促进开花(Blázquez et al., 2003).开花途径重要的调节因子SOC1 (suppressor of overexpression of constans 1)编码1个MADS类转录因子, 研究表明SOC1可以直接结合CBF启动子的CArG元件, 负调节CBF基因的表达(Seo et al., 2009).与此对应, soc1突变体也表现出明显的抗冻性, 说明SOC1是开花途径与低温信号途径相互作用的节点(Seo et al., 2009).自2000年以来, 不断有研究表明, CBF及其下游冷响应基因的表达存在节律现象(Har- mer et al., 2000; Bieniawska et al., 2008; Espinoza et al., 2008; Mikkelsen and Thomashow, 2009), 其基因表达在黎明后8小时达到峰值, 并在黎明后20小时达到低谷.多项研究表明, 节律可以同时正向及负向调控CBF基因的转录水平.节律中心调控因子包括MYB类转录因子CCA1 (circadian clock associated 1)与LHY (late elongated hypocotyl)以及PRR (pseudoresponse regulator)蛋白TOC1, 它们相互调控彼此的基因表达, 从而形成反馈环机制.三突变体prr5/prr7/prr9中CBF基因组成型高水平表达, 并表现出明显的抗冻表型, 暗示PRRs参与抑制CBF基因表达(Nakamichi et al., 2009, 2012).2011年, Thom- ashow实验室发现拟南芥中央振荡器因子CCA1及LHY可以正调控CBF的表达.CCA1及LHY均编码MYB类转录因子, 它们通过结合CBF1-CBF3基因启动子上的EE及CBS结合位点, 直接调控CBF基因表达.cca1/lhy双突变体中CBF基因表达水平大幅下调, 并且CBF基因表达的节律性也有所减弱(Dong et al., 2011).CBF下游调控基因COR15A、COR47及COR78表达水平也显著下调.双突变体在冷驯化前后均表现出敏感表型, 说明节律调控因子CCA1及LHY通过直接调控CBF的表达, 参与低温信号途径(Dong et al., 2011).进一步研究发现, CCA1的2个转录本CCA1α及CCA1β均参与低温信号途径.低温抑制CCA1β的表达, 而CCA1β通过与CCA1α相互作用, 抑制CCA1α的表达(Seo et al., 2012). ... ... 的表达, 参与低温信号途径(Dong et al., 2011).进一步研究发现, CCA1的2个转录本CCA1α及CCA1β均参与低温信号途径.低温抑制CCA1β的表达, 而CCA1β通过与CCA1α相互作用, 抑制CCA1α的表达(Seo et al., 2012). ...
1 2016
... 一系列激素信号途径中的调节组分被证明也会直接或间接参与CBF的转录调控.本实验室最新研究表明, BR信号途径的关键调节因子BZR1 (brassinazole-resistant 1)及其同源蛋白BES1 (BRI1-EMS- suppressor 1)通过结合CBF1与CBF2启动子上的E-box及BRRE结合位点, 正调控二者的表达(Li et al., 2017b).BZR1和BES1都是bHLH类转录因子, 在BR信号途径中起正调控作用(He et al., 2005; Yin et al., 2005), 它们的功能获得型突变体表现出强烈的抗冻表型(Li et al., 2017b).另一个BR信号途径的转录因子CESTA直接结合所有CBF启动子, 并组成性激活CBF及下游COR基因表达, 正调控植物的抗冻性(Eremina et al., 2016).进一步研究发现, 低温可以诱导非磷酸化形式的BZR1蛋白积累, 进而调控其磷酸化的蛋白激酶BIN2 (brassinosteroid insensitive 2)也作为负调节子参与植物的抗冻性调控.转录组分析数据表明, BZR1除了直接调节CBF基因表达, 还参与正向及负向调控一系列不依赖CBF的冷诱导基因的表达, 说明BZR1作为重要的调节因子, 在低温信号途径的精细调控中可能起到不同的关键作用, 而这其中的分子机制还有待进一步研究(Li et al., 2017b). ...
1 2008
... 植物的开花过程也受到低温调控, 低温可抑制开花而高温则促进开花(Blázquez et al., 2003).开花途径重要的调节因子SOC1 (suppressor of overexpression of constans 1)编码1个MADS类转录因子, 研究表明SOC1可以直接结合CBF启动子的CArG元件, 负调节CBF基因的表达(Seo et al., 2009).与此对应, soc1突变体也表现出明显的抗冻性, 说明SOC1是开花途径与低温信号途径相互作用的节点(Seo et al., 2009).自2000年以来, 不断有研究表明, CBF及其下游冷响应基因的表达存在节律现象(Har- mer et al., 2000; Bieniawska et al., 2008; Espinoza et al., 2008; Mikkelsen and Thomashow, 2009), 其基因表达在黎明后8小时达到峰值, 并在黎明后20小时达到低谷.多项研究表明, 节律可以同时正向及负向调控CBF基因的转录水平.节律中心调控因子包括MYB类转录因子CCA1 (circadian clock associated 1)与LHY (late elongated hypocotyl)以及PRR (pseudoresponse regulator)蛋白TOC1, 它们相互调控彼此的基因表达, 从而形成反馈环机制.三突变体prr5/prr7/prr9中CBF基因组成型高水平表达, 并表现出明显的抗冻表型, 暗示PRRs参与抑制CBF基因表达(Nakamichi et al., 2009, 2012).2011年, Thom- ashow实验室发现拟南芥中央振荡器因子CCA1及LHY可以正调控CBF的表达.CCA1及LHY均编码MYB类转录因子, 它们通过结合CBF1-CBF3基因启动子上的EE及CBS结合位点, 直接调控CBF基因表达.cca1/lhy双突变体中CBF基因表达水平大幅下调, 并且CBF基因表达的节律性也有所减弱(Dong et al., 2011).CBF下游调控基因COR15A、COR47及COR78表达水平也显著下调.双突变体在冷驯化前后均表现出敏感表型, 说明节律调控因子CCA1及LHY通过直接调控CBF的表达, 参与低温信号途径(Dong et al., 2011).进一步研究发现, CCA1的2个转录本CCA1α及CCA1β均参与低温信号途径.低温抑制CCA1β的表达, 而CCA1β通过与CCA1α相互作用, 抑制CCA1α的表达(Seo et al., 2012). ...
2 2007
... 除了节律可调控植物对低温的响应, 光信号与光周期也被发现参与植物的抗冻性调节(Franklin and Whitelam, 2007; Lee and Thomashow, 2012).当植物生长在较低温度(16°C)且红光与远红光比(R/FR)降低时, 植物体内的CBF基因节律性表达增强, COR基因表达上调, 使植株产生更强的抗冻性, 这与红光及远红光受体光敏色素有关, 暗示环境温度可通过光敏色素调控CBF基因的节律性及其下游基因的表达(Franklin and Whitelam, 2007).与长日照相比, 生长在短日照下的野生型植株表现出更强的抗冻性, 这可能与短日照下植株中的CBF表达倍数更高有关.进一步研究发现, 长日照下, 2个光受体结合蛋白PIF4和PIF7蛋白水平增加, 它们通过直接结合在CBF3的G-box及E-box区, 负调控CBF的表达.CBF下游靶基因COR15a和Gols3的表达水平同样受到抑制, 因此造成植物抗冻性减弱(Lee and Thomashow, 2012).PIF3蛋白在黑暗时活性增强, 抑制植物的光形态建成(Ni et al., 1998; Leivar et al., 2008; Leivar and Monte, 2014).光照射下, 光敏色素与PIF蛋白相互作用, 促进PIF蛋白降解(Ni et al., 2014).PIF3可以被PRRK蛋白磷酸化并通过LRB Cullin 3 E3泛素连接酶降解(Ni et al., 2014, 2017).本实验室的最新研究表明, 乙烯信号途径的E3泛素连接酶EBF1和EBF2可以通过与PIF3相互作用, 使其经由26S蛋白酶体途径降解(Jiang et al., 2017).PIF3直接结合在CBF基因的启动子区, 负调控其表达, 是植物抗冻性的负调控因子.低温及黑暗条件下, EBF蛋白降解(Shi et al., 2012), 导致PIF3蛋白积累, 从而调控CBF基因的表达(Jiang et al., 2017).以上研究结果暗示, 光和温度对植物冷驯化过程的影响密不可分, PIF作为CBF重要的负调控因子, 平衡植物的抗冻性和生长发育过程. ... ... 基因的节律性及其下游基因的表达(Franklin and Whitelam, 2007).与长日照相比, 生长在短日照下的野生型植株表现出更强的抗冻性, 这可能与短日照下植株中的CBF表达倍数更高有关.进一步研究发现, 长日照下, 2个光受体结合蛋白PIF4和PIF7蛋白水平增加, 它们通过直接结合在CBF3的G-box及E-box区, 负调控CBF的表达.CBF下游靶基因COR15a和Gols3的表达水平同样受到抑制, 因此造成植物抗冻性减弱(Lee and Thomashow, 2012).PIF3蛋白在黑暗时活性增强, 抑制植物的光形态建成(Ni et al., 1998; Leivar et al., 2008; Leivar and Monte, 2014).光照射下, 光敏色素与PIF蛋白相互作用, 促进PIF蛋白降解(Ni et al., 2014).PIF3可以被PRRK蛋白磷酸化并通过LRB Cullin 3 E3泛素连接酶降解(Ni et al., 2014, 2017).本实验室的最新研究表明, 乙烯信号途径的E3泛素连接酶EBF1和EBF2可以通过与PIF3相互作用, 使其经由26S蛋白酶体途径降解(Jiang et al., 2017).PIF3直接结合在CBF基因的启动子区, 负调控其表达, 是植物抗冻性的负调控因子.低温及黑暗条件下, EBF蛋白降解(Shi et al., 2012), 导致PIF3蛋白积累, 从而调控CBF基因的表达(Jiang et al., 2017).以上研究结果暗示, 光和温度对植物冷驯化过程的影响密不可分, PIF作为CBF重要的负调控因子, 平衡植物的抗冻性和生长发育过程. ...
1 2009
... 第1个被鉴定的同时也是研究得最深入的CBF冷响应正调节因子是bHLH类转录因子ICE1 (inducer of CBF expression 1) (Chinnusamy et al., 2003).2003年, 朱健康实验室利用EMS诱变含有ProCBF3:LUC的拟南芥转基因植株, 获得了ice1突变体, 并成功克隆到ICE1基因(Chinnusamy et al., 2003).ICE1编码1个MYC类bHLH家族转录因子, 与野生型相比, ice1突变体植株矮小, 生长发育缓慢, 体内CBF3基因的冷诱导情况被严重抑制, 且抗冻性大幅降低.这些结果表明, ICE1是低温信号途径中的正调控因子(Chinnusamy et al., 2003; Lee et al., 2005).有趣的是, ICE1特异性调节CBF3基因表达, ice1突变体中CBF1及CBF2基因的冷诱导表达下调十分微弱且后期没有影响, 说明ICE1的调节具有特异性.这可能与CBF基因启动子上的MYC结合位点的数目有关(CBF3启动子有5个结合位点, CBF1及CBF2启动子各有1个结合位点).ICE1特异性结合在CBF3启动子的MYC结合位点CANNTG (Meshi and Iwabuchi, 1995), 正调控CBF3基因表达.过表达ICE1可以明显增强植株的抗冻能力(Chinnusamy et al., 2003).最近在水稻、玉米及番茄的研究中发现, ICE1均可以正调控植物的耐寒性, 将这些物种中的ICE1蛋白在拟南芥中过表达均可增强植株的抗冻性, 说明ICE1在低温信号途径中的功能非常保守(Nosenko et al., 2016; Deng et al., 2017; Lu et al., 2017).ICE2作为ICE1的同源基因, 也参与调控植物的抗冻性.过表达ICE2可以显著提高植物的抗冻性, 并且植物体内的CBF1基因也被诱导表达, 暗示ICE2作用在CBF1的上游(Fursova et al., 2009). ...
2 2004
... 遗传分析表明CBF在低温信号途径中起关键作用.例如, 过表达CBF1-3均使拟南芥植株的抗冻性明显增强.进一步检测植物体内的下游冷响应基因, 发现约100个COR基因被组成型诱导, 从而使未经冷驯化的植株也能获得抗冻性(Gilmour et al., 1998; Jaglo- Ottosen et al., 1998; Liu et al., 1998; Kasuga et al., 1999; Gilmour et al., 2004).与野生型相比, CBF1及CBF3敲减拟南芥植株的抗冻性降低约60% (Novillo et al., 2007).在拟南芥中过表达CBF2的DNA结合域形成的dominant negative转基因植株中, CBF2可以结合在CRT/DRE作用位点却不能激活下游基因, 从而使植株呈现冻敏感表型(Park et al., 2015).为了进一步探究CBF1-CBF3的功能, 本实验室和上海植物逆境中心朱健康实验室分别利用CRISPR/Cas9技术获得了cbf1/cbf2/cbf3三突变体(Jia et al., 2016; Zhao et al., 2016).与野生型相比, 三突变体在非冷驯化时没有或具有轻微冻敏感表型, 而在冷驯化后表现出强烈的冻敏感表型.对突变体进行RNA-seq分析, 显示CBF突变影响了全转录组10%-20%的COR基因表达(Jia et al., 2016; Zhao et al., 2016).这些结果表明, CBF1- CBF3在低温信号途径中发挥重要的调控作用. ... ... 一系列研究表明CBF参与植物的生长发育过程.过表达CBF导致植株矮小, 且与野生型相比, 开花时间明显延迟(Gilmour et al., 2004; Park et al., 2015).对突变体的研究表明, cbf1/cbf2/cbf3三突变体种子萌发率与野生型相比降低一半, 根生长速率略慢于野生型, 植株的莲座叶数目减少, 形态偏小, 生物量也低于野生型(Zhao et al., 2016).这些结果说明, CBF是植物生长发育过程中的关键因素.Jia等(2016)研究表明, 低温下无论是土中还是培养皿上生长的cbf1/cbf2/cbf3三突变体植株均明显大于野生型, 说明CBF影响了低温胁迫下植物的生长发育(Jia et al., 2016).有趣的是, 外源施加影响植物细胞伸长的植物激素赤霉素(gibberellin acid, GA)可以回复CBF1过表达植株的生长发育矮小表型(Achard et al., 2008).过表达CBF1可以激活植物体内GA2ox基因的表达, 使植物体内活性形式的GA含量下降, 造成GA信号途径的负调节因子DELLA蛋白在植物体内高水平积累, 从而导致植株生长受到抑制.DELLA基因突变可以部分回复CBF1过表达植株的矮小表型, 这些结果暗示, CBF在生长发育中的作用需要GA及DELLA蛋白的参与(Achard et al., 2008).不仅CBF影响植物的生长发育, CBF的上游调控因子如ICE1、ICE2、EIN3、BZR1、PIF3/4/7和SOC1等也全部参与调控植物的生长发育, 突变体均表现出各种生长发育表型, 这暗示着植物产生对低温胁迫的抗性很可能需要以牺牲生长发育作为代价.最新研究表明, 植物面对低温胁迫时, 会自主启动细胞死亡机制, 优先杀死未成熟的小柱干细胞, 使根部静止中心维持高浓度生长素, 有利于干细胞巢(stem cell niche)抵抗低温胁迫(Hong et al., 2017).但这一机制具有特异性, CBF是否参与这一过程目前仍有待研究.植物面对低温或者其它胁迫可能要做出选择: 是继续正常生长发育从而造成对胁迫的敏感, 还是牺牲生长发育, 利用更多能量产生抵抗物质来对抗逆境? CBF可能参与低温胁迫及生长发育调控, 寻找到一种平衡植物抗冻及生长发育受损的调控机制可能是后续需要认真研究的科学问题. ...
4 1998
... 在拟南芥(Arabidopsis thaliana)基因组中存在3个CBF基因, 属于一类转录因子家族CBF/DREB1 (de- hydration-responsive element-binding factors 1)基因.CBF家族成员串联排列在拟南芥第4条染色体上, 分别命名为CBF1 (DREB1B)、CBF2 (DREB1C)和CBF3 (DREB1A) (Gilmour et al., 1998; Liu et al., 1998).1997-1998年, Thomashow等利用酵母单杂交等技术相继鉴定到了CBF1-CBF3 (Stockinger et al., 1997; Gilmour et al., 1998; Liu et al., 1998), 它们可以与一段保守的CRT/DRE (C-repeat/dehydration response element)调控元件CCGAC结合(Baker et al., 1994), 该元件多出现在冷诱导COR (Cold- regulated)基因的启动子区域(Medina et al., 2011).氨基酸序列比对结果显示, CBF1-CBF3三者之间具有很高的相似性(>85%), 暗示它们可能起源于同一个基因(Gilmour et al., 1998; Medina et al., 1999).过量表达CBF1、CBF2及CBF3均能大幅提高植株的抗冻性, 并显著诱导植株体内COR基因的表达(Liu et al., 1998). ... ... ; Gilmour et al., 1998; Liu et al., 1998), 它们可以与一段保守的CRT/DRE (C-repeat/dehydration response element)调控元件CCGAC结合(Baker et al., 1994), 该元件多出现在冷诱导COR (Cold- regulated)基因的启动子区域(Medina et al., 2011).氨基酸序列比对结果显示, CBF1-CBF3三者之间具有很高的相似性(>85%), 暗示它们可能起源于同一个基因(Gilmour et al., 1998; Medina et al., 1999).过量表达CBF1、CBF2及CBF3均能大幅提高植株的抗冻性, 并显著诱导植株体内COR基因的表达(Liu et al., 1998). ... ... ).氨基酸序列比对结果显示, CBF1-CBF3三者之间具有很高的相似性(>85%), 暗示它们可能起源于同一个基因(Gilmour et al., 1998; Medina et al., 1999).过量表达CBF1、CBF2及CBF3均能大幅提高植株的抗冻性, 并显著诱导植株体内COR基因的表达(Liu et al., 1998). ... ... 遗传分析表明CBF在低温信号途径中起关键作用.例如, 过表达CBF1-3均使拟南芥植株的抗冻性明显增强.进一步检测植物体内的下游冷响应基因, 发现约100个COR基因被组成型诱导, 从而使未经冷驯化的植株也能获得抗冻性(Gilmour et al., 1998; Jaglo- Ottosen et al., 1998; Liu et al., 1998; Kasuga et al., 1999; Gilmour et al., 2004).与野生型相比, CBF1及CBF3敲减拟南芥植株的抗冻性降低约60% (Novillo et al., 2007).在拟南芥中过表达CBF2的DNA结合域形成的dominant negative转基因植株中, CBF2可以结合在CRT/DRE作用位点却不能激活下游基因, 从而使植株呈现冻敏感表型(Park et al., 2015).为了进一步探究CBF1-CBF3的功能, 本实验室和上海植物逆境中心朱健康实验室分别利用CRISPR/Cas9技术获得了cbf1/cbf2/cbf3三突变体(Jia et al., 2016; Zhao et al., 2016).与野生型相比, 三突变体在非冷驯化时没有或具有轻微冻敏感表型, 而在冷驯化后表现出强烈的冻敏感表型.对突变体进行RNA-seq分析, 显示CBF突变影响了全转录组10%-20%的COR基因表达(Jia et al., 2016; Zhao et al., 2016).这些结果表明, CBF1- CBF3在低温信号途径中发挥重要的调控作用. ...
1 2000
... 植物的开花过程也受到低温调控, 低温可抑制开花而高温则促进开花(Blázquez et al., 2003).开花途径重要的调节因子SOC1 (suppressor of overexpression of constans 1)编码1个MADS类转录因子, 研究表明SOC1可以直接结合CBF启动子的CArG元件, 负调节CBF基因的表达(Seo et al., 2009).与此对应, soc1突变体也表现出明显的抗冻性, 说明SOC1是开花途径与低温信号途径相互作用的节点(Seo et al., 2009).自2000年以来, 不断有研究表明, CBF及其下游冷响应基因的表达存在节律现象(Har- mer et al., 2000; Bieniawska et al., 2008; Espinoza et al., 2008; Mikkelsen and Thomashow, 2009), 其基因表达在黎明后8小时达到峰值, 并在黎明后20小时达到低谷.多项研究表明, 节律可以同时正向及负向调控CBF基因的转录水平.节律中心调控因子包括MYB类转录因子CCA1 (circadian clock associated 1)与LHY (late elongated hypocotyl)以及PRR (pseudoresponse regulator)蛋白TOC1, 它们相互调控彼此的基因表达, 从而形成反馈环机制.三突变体prr5/prr7/prr9中CBF基因组成型高水平表达, 并表现出明显的抗冻表型, 暗示PRRs参与抑制CBF基因表达(Nakamichi et al., 2009, 2012).2011年, Thom- ashow实验室发现拟南芥中央振荡器因子CCA1及LHY可以正调控CBF的表达.CCA1及LHY均编码MYB类转录因子, 它们通过结合CBF1-CBF3基因启动子上的EE及CBS结合位点, 直接调控CBF基因表达.cca1/lhy双突变体中CBF基因表达水平大幅下调, 并且CBF基因表达的节律性也有所减弱(Dong et al., 2011).CBF下游调控基因COR15A、COR47及COR78表达水平也显著下调.双突变体在冷驯化前后均表现出敏感表型, 说明节律调控因子CCA1及LHY通过直接调控CBF的表达, 参与低温信号途径(Dong et al., 2011).进一步研究发现, CCA1的2个转录本CCA1α及CCA1β均参与低温信号途径.低温抑制CCA1β的表达, 而CCA1β通过与CCA1α相互作用, 抑制CCA1α的表达(Seo et al., 2012). ...
1 2005
... 一系列激素信号途径中的调节组分被证明也会直接或间接参与CBF的转录调控.本实验室最新研究表明, BR信号途径的关键调节因子BZR1 (brassinazole-resistant 1)及其同源蛋白BES1 (BRI1-EMS- suppressor 1)通过结合CBF1与CBF2启动子上的E-box及BRRE结合位点, 正调控二者的表达(Li et al., 2017b).BZR1和BES1都是bHLH类转录因子, 在BR信号途径中起正调控作用(He et al., 2005; Yin et al., 2005), 它们的功能获得型突变体表现出强烈的抗冻表型(Li et al., 2017b).另一个BR信号途径的转录因子CESTA直接结合所有CBF启动子, 并组成性激活CBF及下游COR基因表达, 正调控植物的抗冻性(Eremina et al., 2016).进一步研究发现, 低温可以诱导非磷酸化形式的BZR1蛋白积累, 进而调控其磷酸化的蛋白激酶BIN2 (brassinosteroid insensitive 2)也作为负调节子参与植物的抗冻性调控.转录组分析数据表明, BZR1除了直接调节CBF基因表达, 还参与正向及负向调控一系列不依赖CBF的冷诱导基因的表达, 说明BZR1作为重要的调节因子, 在低温信号途径的精细调控中可能起到不同的关键作用, 而这其中的分子机制还有待进一步研究(Li et al., 2017b). ...
1 2017
... 一系列研究表明CBF参与植物的生长发育过程.过表达CBF导致植株矮小, 且与野生型相比, 开花时间明显延迟(Gilmour et al., 2004; Park et al., 2015).对突变体的研究表明, cbf1/cbf2/cbf3三突变体种子萌发率与野生型相比降低一半, 根生长速率略慢于野生型, 植株的莲座叶数目减少, 形态偏小, 生物量也低于野生型(Zhao et al., 2016).这些结果说明, CBF是植物生长发育过程中的关键因素.Jia等(2016)研究表明, 低温下无论是土中还是培养皿上生长的cbf1/cbf2/cbf3三突变体植株均明显大于野生型, 说明CBF影响了低温胁迫下植物的生长发育(Jia et al., 2016).有趣的是, 外源施加影响植物细胞伸长的植物激素赤霉素(gibberellin acid, GA)可以回复CBF1过表达植株的生长发育矮小表型(Achard et al., 2008).过表达CBF1可以激活植物体内GA2ox基因的表达, 使植物体内活性形式的GA含量下降, 造成GA信号途径的负调节因子DELLA蛋白在植物体内高水平积累, 从而导致植株生长受到抑制.DELLA基因突变可以部分回复CBF1过表达植株的矮小表型, 这些结果暗示, CBF在生长发育中的作用需要GA及DELLA蛋白的参与(Achard et al., 2008).不仅CBF影响植物的生长发育, CBF的上游调控因子如ICE1、ICE2、EIN3、BZR1、PIF3/4/7和SOC1等也全部参与调控植物的生长发育, 突变体均表现出各种生长发育表型, 这暗示着植物产生对低温胁迫的抗性很可能需要以牺牲生长发育作为代价.最新研究表明, 植物面对低温胁迫时, 会自主启动细胞死亡机制, 优先杀死未成熟的小柱干细胞, 使根部静止中心维持高浓度生长素, 有利于干细胞巢(stem cell niche)抵抗低温胁迫(Hong et al., 2017).但这一机制具有特异性, CBF是否参与这一过程目前仍有待研究.植物面对低温或者其它胁迫可能要做出选择: 是继续正常生长发育从而造成对胁迫的敏感, 还是牺牲生长发育, 利用更多能量产生抵抗物质来对抗逆境? CBF可能参与低温胁迫及生长发育调控, 寻找到一种平衡植物抗冻及生长发育受损的调控机制可能是后续需要认真研究的科学问题. ...
2 2013
... ICE1作为重要的CBF调节因子, 自身也被很多组分精细调控.目前已知的对ICE1的翻译后修饰包括HOS1 (high osmotic expression 1)介导的泛素化、SIZ1 (SAP and Miz 1)介导的SUMO化以及OST1 (open stomata 1)介导的磷酸化等, 这些修饰通过调节ICE1的蛋白水平或转录水平参与调控冷信号途径.同时一些转录抑制子(MYB15和JAZ)还可以与ICE1相互作用, 从而调节它的转录活性.HOS1与ICE1相互作用, 泛素化ICE1蛋白, 使其通过26S蛋白酶体途径进行降解(Dong et al., 2006).HOS1过表达植株中CBF3基因表达水平下调, 植株表现出冻敏感表型(Dong et al., 2006).ICE1还受到另一种E3蛋白SIZ1的SUMO化调控(Miura et al., 2007).SIZ1使ICE1蛋白SUMO化, 并减弱ICE1的泛素化, 从而维持ICE1蛋白的稳定性.siz1突变体中CBF3基因表达水平下调, 植株呈冻敏感表型(Miura et al., 2007).JA信号途径的负调节因子JAZ1 (jasmonate ZIM-domain)与JAZ4通过与ICE1蛋白具有bHLH结构域的C端相互作用, 抑制ICE1的转录活性, 从而参与对低温信号途径的调控(Hu et al., 2013).与之相对应, 过表达JAZ1及JAZ4的转基因植株, 以及JA合成途径及信号途径中一些组分的突变体均表现出低温敏感的表型(Hu et al., 2013).本实验室研究表明, 低温可以激活ABA信号途径中的重要激酶OST1, 使其磷酸化ICE1第278位Ser, 正调控ICE1蛋白的稳定性及转录活性, 从而促进下游CBF基因的表达(Ding et al., 2015).OST1对ICE1的磷酸化作用还可以抑制其与HOS1的互作, 从而抑制HOS1对ICE1的降解.以上结果说明OST1作为蛋白激酶, 在低温信号途径中起关键正调控作用(Ding et al., 2015).除此之外, 本实验室及朱健康研究组同时发现, 低温可以激活丝裂原活化蛋白激酶MPK3及MPK6, 它们通过磷酸化ICE1 (磷酸化位点与OST1对ICE1的磷酸化位点不同), 抑制ICE1蛋白的稳定性和转录活性, 从而负调控CBF基因表达及植物的抗冻性(Li et al., 2017a; Zhao et al., 2017).这些结果说明, ICE1作为重要的低温信号途径的转录因子, 被多种调节子不同程度地调控, 从而使植物更好地应对低温胁迫, 做出精细的应答反应. ... ... ).与之相对应, 过表达JAZ1及JAZ4的转基因植株, 以及JA合成途径及信号途径中一些组分的突变体均表现出低温敏感的表型(Hu et al., 2013).本实验室研究表明, 低温可以激活ABA信号途径中的重要激酶OST1, 使其磷酸化ICE1第278位Ser, 正调控ICE1蛋白的稳定性及转录活性, 从而促进下游CBF基因的表达(Ding et al., 2015).OST1对ICE1的磷酸化作用还可以抑制其与HOS1的互作, 从而抑制HOS1对ICE1的降解.以上结果说明OST1作为蛋白激酶, 在低温信号途径中起关键正调控作用(Ding et al., 2015).除此之外, 本实验室及朱健康研究组同时发现, 低温可以激活丝裂原活化蛋白激酶MPK3及MPK6, 它们通过磷酸化ICE1 (磷酸化位点与OST1对ICE1的磷酸化位点不同), 抑制ICE1蛋白的稳定性和转录活性, 从而负调控CBF基因表达及植物的抗冻性(Li et al., 2017a; Zhao et al., 2017).这些结果说明, ICE1作为重要的低温信号途径的转录因子, 被多种调节子不同程度地调控, 从而使植物更好地应对低温胁迫, 做出精细的应答反应. ...
3 2001
... CBF属于AP2/ERF (APETALA 2/ethylene-res- ponsive)转录因子家族成员的一个亚家族.该家族在拟南芥中有145个成员, 均含有1个或多个保守的AP2/ ERF结构域(Ohme-Takagi and Shinshi, 1995).研究表明该结构域是转录因子中的DNA结合区域(Okam- uro et al., 1997; Riechmann and Meyerowitz, 1998).不同于AP2家族的其它亚家族, CBF家族成员只有1个AP2结构域, 并且在AP2的上下游各有一段保守的氨基酸序列PKKP/PKKPAGR (RAGRxxKFx ETRHP)和DSAWR (Jaglo et al., 2001; Canella et al., 2010).将PKKPAGR突变可以抑制CBF1与其下游基因COR- 15a启动子CRT/DRE的结合能力, 从而削弱CBF1对COR15a基因的冷诱导水平调控, 说明该基序对CBF行使其转录因子功能是必需的(Canella et al., 2010). ... ... 截至目前, 在油菜(Brassica campestris)、小麦(Triticum aestivum)、黑麦(Secale cereale)、番茄(Lycopersicon esculentum)、水稻(Oryza sativa)及玉米(Zea mays)等植物中均鉴定到了CBF转录因子(Jaglo et al., 2001; Kasuga et al., 2004; Qin et al., 2004), 并且都具有冷诱导特性; 同时, 在其它物种中过表达拟南芥CBF也可以增强植物的抗冻性(Jaglo et al., 2001; Kasuga et al., 2004).在拟南芥中过表达玉米DREB1A也会产生类似的抗冻效果(Qin et al., 2004), 说明植物中CBF在低温信号途径中的作用十分保守.虽然一些研究结果暗示, CBF1-CBF3在调节冷响应基因的功能上具有冗余性(Park et al., 2015), 但它们之间实则存在差异.首先, 三者的表达模式有所差异: CBF1及CBF3主要在根、下胚轴及子叶中表达; 而CBF2则在下胚轴、子叶及第1、2对真叶中表达, 并不在根中表达(Novillo et al., 2007).当植株遭受低温胁迫时, CBF1及CBF3基因在叶片、萼片及角果中表达, 而CBF2还在茎中表达(Novillo et al., 2007).其次, 基因表达分析显示, CBF1及CBF3表达水平在低温诱导1个小时左右即达到峰值, 而CBF2则需要2小时才会达到峰值.低温条件下, CBF2还可以负反馈调节CBF1和CBF3的表达(Novillo et al., 2004), 如启动子区域插入T-DNA的cbf2突变体表现出抗冻的表型, 这可能是由于突变体中CBF1及CBF3基因过量表达造成的(Novillo et al., 2004, 2007).然而, Zhao等(2016)利用CRISPR/Cas9产生的cbf2突变体表现出冻敏感表型.目前, 猜测cbf突变体的以上表型差异可能是由于突变形式不同或植株生长状态不同等原因所致.由于CBF基因的启动子上没有CRT/DRE作用元件, 因此CBF2对CBF1及CBF3的转录调控可能不是直接的, 这其中的分子机制有待进一步研究.CBF1及CBF3的RNAi植株以及CBF1、CBF3的antisense植株中, CBF2的表达量并没有变化(Novillo et al., 2007).最近, Jia等(2016)研究表明, 利用CRISPR/Cas9产生的cbf1/cbf3双突变体在冷驯化后也具有敏感表型.这些结果暗示, CBF1和CBF3并不能调控CBF2基因的表达.有趣的是, 朱健康实验室利用CRISPR/Cas9技术获得的cbf1/cbf3双突变体中, CBF2的表达有2倍左右的上调, 并且在冷驯化后具有显著的抗冻表型(Zhao et al., 2016).因此, CBF1-CBF3相互的调控关系仍有待进一步研究.虽然以上2项研究中, cbf单突变体和双突变体的抗冻表型及基因表达水平有所不同, 但是cbf1/cbf2/cbf3三突变体的表型非常一致, 均是在冷驯化后产生极度冻敏感的表型(Jia et al., 2016; Zhao et al., 2016).与cbf1/cbf3双突变体的冷驯化表型相比可以得出结论, 在冷驯化后的植物抗冻性中, 相较于CBF1及CBF3, CBF2发挥更重要的作用(Zhao et al., 2016). ... ... 也可以增强植物的抗冻性(Jaglo et al., 2001; Kasuga et al., 2004).在拟南芥中过表达玉米DREB1A也会产生类似的抗冻效果(Qin et al., 2004), 说明植物中CBF在低温信号途径中的作用十分保守.虽然一些研究结果暗示, CBF1-CBF3在调节冷响应基因的功能上具有冗余性(Park et al., 2015), 但它们之间实则存在差异.首先, 三者的表达模式有所差异: CBF1及CBF3主要在根、下胚轴及子叶中表达; 而CBF2则在下胚轴、子叶及第1、2对真叶中表达, 并不在根中表达(Novillo et al., 2007).当植株遭受低温胁迫时, CBF1及CBF3基因在叶片、萼片及角果中表达, 而CBF2还在茎中表达(Novillo et al., 2007).其次, 基因表达分析显示, CBF1及CBF3表达水平在低温诱导1个小时左右即达到峰值, 而CBF2则需要2小时才会达到峰值.低温条件下, CBF2还可以负反馈调节CBF1和CBF3的表达(Novillo et al., 2004), 如启动子区域插入T-DNA的cbf2突变体表现出抗冻的表型, 这可能是由于突变体中CBF1及CBF3基因过量表达造成的(Novillo et al., 2004, 2007).然而, Zhao等(2016)利用CRISPR/Cas9产生的cbf2突变体表现出冻敏感表型.目前, 猜测cbf突变体的以上表型差异可能是由于突变形式不同或植株生长状态不同等原因所致.由于CBF基因的启动子上没有CRT/DRE作用元件, 因此CBF2对CBF1及CBF3的转录调控可能不是直接的, 这其中的分子机制有待进一步研究.CBF1及CBF3的RNAi植株以及CBF1、CBF3的antisense植株中, CBF2的表达量并没有变化(Novillo et al., 2007).最近, Jia等(2016)研究表明, 利用CRISPR/Cas9产生的cbf1/cbf3双突变体在冷驯化后也具有敏感表型.这些结果暗示, CBF1和CBF3并不能调控CBF2基因的表达.有趣的是, 朱健康实验室利用CRISPR/Cas9技术获得的cbf1/cbf3双突变体中, CBF2的表达有2倍左右的上调, 并且在冷驯化后具有显著的抗冻表型(Zhao et al., 2016).因此, CBF1-CBF3相互的调控关系仍有待进一步研究.虽然以上2项研究中, cbf单突变体和双突变体的抗冻表型及基因表达水平有所不同, 但是cbf1/cbf2/cbf3三突变体的表型非常一致, 均是在冷驯化后产生极度冻敏感的表型(Jia et al., 2016; Zhao et al., 2016).与cbf1/cbf3双突变体的冷驯化表型相比可以得出结论, 在冷驯化后的植物抗冻性中, 相较于CBF1及CBF3, CBF2发挥更重要的作用(Zhao et al., 2016). ...
1 1998
... 遗传分析表明CBF在低温信号途径中起关键作用.例如, 过表达CBF1-3均使拟南芥植株的抗冻性明显增强.进一步检测植物体内的下游冷响应基因, 发现约100个COR基因被组成型诱导, 从而使未经冷驯化的植株也能获得抗冻性(Gilmour et al., 1998; Jaglo- Ottosen et al., 1998; Liu et al., 1998; Kasuga et al., 1999; Gilmour et al., 2004).与野生型相比, CBF1及CBF3敲减拟南芥植株的抗冻性降低约60% (Novillo et al., 2007).在拟南芥中过表达CBF2的DNA结合域形成的dominant negative转基因植株中, CBF2可以结合在CRT/DRE作用位点却不能激活下游基因, 从而使植株呈现冻敏感表型(Park et al., 2015).为了进一步探究CBF1-CBF3的功能, 本实验室和上海植物逆境中心朱健康实验室分别利用CRISPR/Cas9技术获得了cbf1/cbf2/cbf3三突变体(Jia et al., 2016; Zhao et al., 2016).与野生型相比, 三突变体在非冷驯化时没有或具有轻微冻敏感表型, 而在冷驯化后表现出强烈的冻敏感表型.对突变体进行RNA-seq分析, 显示CBF突变影响了全转录组10%-20%的COR基因表达(Jia et al., 2016; Zhao et al., 2016).这些结果表明, CBF1- CBF3在低温信号途径中发挥重要的调控作用. ...
5 2016
... 遗传分析表明CBF在低温信号途径中起关键作用.例如, 过表达CBF1-3均使拟南芥植株的抗冻性明显增强.进一步检测植物体内的下游冷响应基因, 发现约100个COR基因被组成型诱导, 从而使未经冷驯化的植株也能获得抗冻性(Gilmour et al., 1998; Jaglo- Ottosen et al., 1998; Liu et al., 1998; Kasuga et al., 1999; Gilmour et al., 2004).与野生型相比, CBF1及CBF3敲减拟南芥植株的抗冻性降低约60% (Novillo et al., 2007).在拟南芥中过表达CBF2的DNA结合域形成的dominant negative转基因植株中, CBF2可以结合在CRT/DRE作用位点却不能激活下游基因, 从而使植株呈现冻敏感表型(Park et al., 2015).为了进一步探究CBF1-CBF3的功能, 本实验室和上海植物逆境中心朱健康实验室分别利用CRISPR/Cas9技术获得了cbf1/cbf2/cbf3三突变体(Jia et al., 2016; Zhao et al., 2016).与野生型相比, 三突变体在非冷驯化时没有或具有轻微冻敏感表型, 而在冷驯化后表现出强烈的冻敏感表型.对突变体进行RNA-seq分析, 显示CBF突变影响了全转录组10%-20%的COR基因表达(Jia et al., 2016; Zhao et al., 2016).这些结果表明, CBF1- CBF3在低温信号途径中发挥重要的调控作用. ... ... 基因表达(Jia et al., 2016; Zhao et al., 2016).这些结果表明, CBF1- CBF3在低温信号途径中发挥重要的调控作用. ... ... 截至目前, 在油菜(Brassica campestris)、小麦(Triticum aestivum)、黑麦(Secale cereale)、番茄(Lycopersicon esculentum)、水稻(Oryza sativa)及玉米(Zea mays)等植物中均鉴定到了CBF转录因子(Jaglo et al., 2001; Kasuga et al., 2004; Qin et al., 2004), 并且都具有冷诱导特性; 同时, 在其它物种中过表达拟南芥CBF也可以增强植物的抗冻性(Jaglo et al., 2001; Kasuga et al., 2004).在拟南芥中过表达玉米DREB1A也会产生类似的抗冻效果(Qin et al., 2004), 说明植物中CBF在低温信号途径中的作用十分保守.虽然一些研究结果暗示, CBF1-CBF3在调节冷响应基因的功能上具有冗余性(Park et al., 2015), 但它们之间实则存在差异.首先, 三者的表达模式有所差异: CBF1及CBF3主要在根、下胚轴及子叶中表达; 而CBF2则在下胚轴、子叶及第1、2对真叶中表达, 并不在根中表达(Novillo et al., 2007).当植株遭受低温胁迫时, CBF1及CBF3基因在叶片、萼片及角果中表达, 而CBF2还在茎中表达(Novillo et al., 2007).其次, 基因表达分析显示, CBF1及CBF3表达水平在低温诱导1个小时左右即达到峰值, 而CBF2则需要2小时才会达到峰值.低温条件下, CBF2还可以负反馈调节CBF1和CBF3的表达(Novillo et al., 2004), 如启动子区域插入T-DNA的cbf2突变体表现出抗冻的表型, 这可能是由于突变体中CBF1及CBF3基因过量表达造成的(Novillo et al., 2004, 2007).然而, Zhao等(2016)利用CRISPR/Cas9产生的cbf2突变体表现出冻敏感表型.目前, 猜测cbf突变体的以上表型差异可能是由于突变形式不同或植株生长状态不同等原因所致.由于CBF基因的启动子上没有CRT/DRE作用元件, 因此CBF2对CBF1及CBF3的转录调控可能不是直接的, 这其中的分子机制有待进一步研究.CBF1及CBF3的RNAi植株以及CBF1、CBF3的antisense植株中, CBF2的表达量并没有变化(Novillo et al., 2007).最近, Jia等(2016)研究表明, 利用CRISPR/Cas9产生的cbf1/cbf3双突变体在冷驯化后也具有敏感表型.这些结果暗示, CBF1和CBF3并不能调控CBF2基因的表达.有趣的是, 朱健康实验室利用CRISPR/Cas9技术获得的cbf1/cbf3双突变体中, CBF2的表达有2倍左右的上调, 并且在冷驯化后具有显著的抗冻表型(Zhao et al., 2016).因此, CBF1-CBF3相互的调控关系仍有待进一步研究.虽然以上2项研究中, cbf单突变体和双突变体的抗冻表型及基因表达水平有所不同, 但是cbf1/cbf2/cbf3三突变体的表型非常一致, 均是在冷驯化后产生极度冻敏感的表型(Jia et al., 2016; Zhao et al., 2016).与cbf1/cbf3双突变体的冷驯化表型相比可以得出结论, 在冷驯化后的植物抗冻性中, 相较于CBF1及CBF3, CBF2发挥更重要的作用(Zhao et al., 2016). ... ... 尽管CBF在冷诱导基因调控中发挥重要作用, 但植物中还存在其它转录因子调控COR基因.Thom- show实验室通过对CBF过表达株系的RNA-seq数据分析, 发现CBF2与转录因子HSFC1、ZAT12、ZF、ZAT10及CZF1共同调控下游COR基因(当然也有像GOL3这样完全依赖CBF的冷响应基因) (Park et al., 2015), 同时多项研究表明植物中也存在不依赖于CBF的冷响应基因(Achard et al., 2008; Park et al., 2015; Jia et al., 2016; Zhao et al., 2016), 表明植物中的冷响应基因调控网络非常复杂且具有内在联系, 这其中的更多调控机制还有待进一步研究. ... ... 一系列研究表明CBF参与植物的生长发育过程.过表达CBF导致植株矮小, 且与野生型相比, 开花时间明显延迟(Gilmour et al., 2004; Park et al., 2015).对突变体的研究表明, cbf1/cbf2/cbf3三突变体种子萌发率与野生型相比降低一半, 根生长速率略慢于野生型, 植株的莲座叶数目减少, 形态偏小, 生物量也低于野生型(Zhao et al., 2016).这些结果说明, CBF是植物生长发育过程中的关键因素.Jia等(2016)研究表明, 低温下无论是土中还是培养皿上生长的cbf1/cbf2/cbf3三突变体植株均明显大于野生型, 说明CBF影响了低温胁迫下植物的生长发育(Jia et al., 2016).有趣的是, 外源施加影响植物细胞伸长的植物激素赤霉素(gibberellin acid, GA)可以回复CBF1过表达植株的生长发育矮小表型(Achard et al., 2008).过表达CBF1可以激活植物体内GA2ox基因的表达, 使植物体内活性形式的GA含量下降, 造成GA信号途径的负调节因子DELLA蛋白在植物体内高水平积累, 从而导致植株生长受到抑制.DELLA基因突变可以部分回复CBF1过表达植株的矮小表型, 这些结果暗示, CBF在生长发育中的作用需要GA及DELLA蛋白的参与(Achard et al., 2008).不仅CBF影响植物的生长发育, CBF的上游调控因子如ICE1、ICE2、EIN3、BZR1、PIF3/4/7和SOC1等也全部参与调控植物的生长发育, 突变体均表现出各种生长发育表型, 这暗示着植物产生对低温胁迫的抗性很可能需要以牺牲生长发育作为代价.最新研究表明, 植物面对低温胁迫时, 会自主启动细胞死亡机制, 优先杀死未成熟的小柱干细胞, 使根部静止中心维持高浓度生长素, 有利于干细胞巢(stem cell niche)抵抗低温胁迫(Hong et al., 2017).但这一机制具有特异性, CBF是否参与这一过程目前仍有待研究.植物面对低温或者其它胁迫可能要做出选择: 是继续正常生长发育从而造成对胁迫的敏感, 还是牺牲生长发育, 利用更多能量产生抵抗物质来对抗逆境? CBF可能参与低温胁迫及生长发育调控, 寻找到一种平衡植物抗冻及生长发育受损的调控机制可能是后续需要认真研究的科学问题. ...
2 2017
... 除了节律可调控植物对低温的响应, 光信号与光周期也被发现参与植物的抗冻性调节(Franklin and Whitelam, 2007; Lee and Thomashow, 2012).当植物生长在较低温度(16°C)且红光与远红光比(R/FR)降低时, 植物体内的CBF基因节律性表达增强, COR基因表达上调, 使植株产生更强的抗冻性, 这与红光及远红光受体光敏色素有关, 暗示环境温度可通过光敏色素调控CBF基因的节律性及其下游基因的表达(Franklin and Whitelam, 2007).与长日照相比, 生长在短日照下的野生型植株表现出更强的抗冻性, 这可能与短日照下植株中的CBF表达倍数更高有关.进一步研究发现, 长日照下, 2个光受体结合蛋白PIF4和PIF7蛋白水平增加, 它们通过直接结合在CBF3的G-box及E-box区, 负调控CBF的表达.CBF下游靶基因COR15a和Gols3的表达水平同样受到抑制, 因此造成植物抗冻性减弱(Lee and Thomashow, 2012).PIF3蛋白在黑暗时活性增强, 抑制植物的光形态建成(Ni et al., 1998; Leivar et al., 2008; Leivar and Monte, 2014).光照射下, 光敏色素与PIF蛋白相互作用, 促进PIF蛋白降解(Ni et al., 2014).PIF3可以被PRRK蛋白磷酸化并通过LRB Cullin 3 E3泛素连接酶降解(Ni et al., 2014, 2017).本实验室的最新研究表明, 乙烯信号途径的E3泛素连接酶EBF1和EBF2可以通过与PIF3相互作用, 使其经由26S蛋白酶体途径降解(Jiang et al., 2017).PIF3直接结合在CBF基因的启动子区, 负调控其表达, 是植物抗冻性的负调控因子.低温及黑暗条件下, EBF蛋白降解(Shi et al., 2012), 导致PIF3蛋白积累, 从而调控CBF基因的表达(Jiang et al., 2017).以上研究结果暗示, 光和温度对植物冷驯化过程的影响密不可分, PIF作为CBF重要的负调控因子, 平衡植物的抗冻性和生长发育过程. ... ... 基因的表达(Jiang et al., 2017).以上研究结果暗示, 光和温度对植物冷驯化过程的影响密不可分, PIF作为CBF重要的负调控因子, 平衡植物的抗冻性和生长发育过程. ...
1 2016
... 另一个非常值得关注的问题是作用于CBF最上游的植物低温感受器究竟是什么? 2015年, 种康课题组通过QTL发现水稻中的COLD1基因介导粳稻耐冷性(Ma et al., 2015).COLD1定位在细胞质膜和内质网膜上, 与拟南芥中G蛋白α亚基互作蛋白GTG1/2高度同源, 被认为是一个低温感受器.它通过与G蛋白α亚基互作, 影响G蛋白活性, 调控低温激活的Ca2+内流, 从而影响籼稻的耐冷性.基因表达分析显示COLD1的互补株系中CBF基因表达上调, 说明COLD1可能参与CBF的调控.该基因上的1个SNP是影响水稻耐冷的关键位点, 暗示COLD1基因在自然选择过程中的重要性(Ma et al., 2015).那么除此之外是否还有其它的低温感受器存在? 蓝藻中的温度感受器Hik33是一类组蛋白激酶(Zabulon et al., 2007; Shimura et al., 2012).植物中的组蛋白激酶作为激素受体发挥重要作用, 它们是否也是低温的感受器? 还有研究表明光受体phyB作为温度感受器调控植物对室温环境温度的感受(Jung et al., 2016; Legris et al., 2016), 但其是否参与低温的感受仍不清楚, 这些问题都有待进一步验证. ...
1 1999
... 遗传分析表明CBF在低温信号途径中起关键作用.例如, 过表达CBF1-3均使拟南芥植株的抗冻性明显增强.进一步检测植物体内的下游冷响应基因, 发现约100个COR基因被组成型诱导, 从而使未经冷驯化的植株也能获得抗冻性(Gilmour et al., 1998; Jaglo- Ottosen et al., 1998; Liu et al., 1998; Kasuga et al., 1999; Gilmour et al., 2004).与野生型相比, CBF1及CBF3敲减拟南芥植株的抗冻性降低约60% (Novillo et al., 2007).在拟南芥中过表达CBF2的DNA结合域形成的dominant negative转基因植株中, CBF2可以结合在CRT/DRE作用位点却不能激活下游基因, 从而使植株呈现冻敏感表型(Park et al., 2015).为了进一步探究CBF1-CBF3的功能, 本实验室和上海植物逆境中心朱健康实验室分别利用CRISPR/Cas9技术获得了cbf1/cbf2/cbf3三突变体(Jia et al., 2016; Zhao et al., 2016).与野生型相比, 三突变体在非冷驯化时没有或具有轻微冻敏感表型, 而在冷驯化后表现出强烈的冻敏感表型.对突变体进行RNA-seq分析, 显示CBF突变影响了全转录组10%-20%的COR基因表达(Jia et al., 2016; Zhao et al., 2016).这些结果表明, CBF1- CBF3在低温信号途径中发挥重要的调控作用. ...
2 2004
... 截至目前, 在油菜(Brassica campestris)、小麦(Triticum aestivum)、黑麦(Secale cereale)、番茄(Lycopersicon esculentum)、水稻(Oryza sativa)及玉米(Zea mays)等植物中均鉴定到了CBF转录因子(Jaglo et al., 2001; Kasuga et al., 2004; Qin et al., 2004), 并且都具有冷诱导特性; 同时, 在其它物种中过表达拟南芥CBF也可以增强植物的抗冻性(Jaglo et al., 2001; Kasuga et al., 2004).在拟南芥中过表达玉米DREB1A也会产生类似的抗冻效果(Qin et al., 2004), 说明植物中CBF在低温信号途径中的作用十分保守.虽然一些研究结果暗示, CBF1-CBF3在调节冷响应基因的功能上具有冗余性(Park et al., 2015), 但它们之间实则存在差异.首先, 三者的表达模式有所差异: CBF1及CBF3主要在根、下胚轴及子叶中表达; 而CBF2则在下胚轴、子叶及第1、2对真叶中表达, 并不在根中表达(Novillo et al., 2007).当植株遭受低温胁迫时, CBF1及CBF3基因在叶片、萼片及角果中表达, 而CBF2还在茎中表达(Novillo et al., 2007).其次, 基因表达分析显示, CBF1及CBF3表达水平在低温诱导1个小时左右即达到峰值, 而CBF2则需要2小时才会达到峰值.低温条件下, CBF2还可以负反馈调节CBF1和CBF3的表达(Novillo et al., 2004), 如启动子区域插入T-DNA的cbf2突变体表现出抗冻的表型, 这可能是由于突变体中CBF1及CBF3基因过量表达造成的(Novillo et al., 2004, 2007).然而, Zhao等(2016)利用CRISPR/Cas9产生的cbf2突变体表现出冻敏感表型.目前, 猜测cbf突变体的以上表型差异可能是由于突变形式不同或植株生长状态不同等原因所致.由于CBF基因的启动子上没有CRT/DRE作用元件, 因此CBF2对CBF1及CBF3的转录调控可能不是直接的, 这其中的分子机制有待进一步研究.CBF1及CBF3的RNAi植株以及CBF1、CBF3的antisense植株中, CBF2的表达量并没有变化(Novillo et al., 2007).最近, Jia等(2016)研究表明, 利用CRISPR/Cas9产生的cbf1/cbf3双突变体在冷驯化后也具有敏感表型.这些结果暗示, CBF1和CBF3并不能调控CBF2基因的表达.有趣的是, 朱健康实验室利用CRISPR/Cas9技术获得的cbf1/cbf3双突变体中, CBF2的表达有2倍左右的上调, 并且在冷驯化后具有显著的抗冻表型(Zhao et al., 2016).因此, CBF1-CBF3相互的调控关系仍有待进一步研究.虽然以上2项研究中, cbf单突变体和双突变体的抗冻表型及基因表达水平有所不同, 但是cbf1/cbf2/cbf3三突变体的表型非常一致, 均是在冷驯化后产生极度冻敏感的表型(Jia et al., 2016; Zhao et al., 2016).与cbf1/cbf3双突变体的冷驯化表型相比可以得出结论, 在冷驯化后的植物抗冻性中, 相较于CBF1及CBF3, CBF2发挥更重要的作用(Zhao et al., 2016). ... ... ; Kasuga et al., 2004).在拟南芥中过表达玉米DREB1A也会产生类似的抗冻效果(Qin et al., 2004), 说明植物中CBF在低温信号途径中的作用十分保守.虽然一些研究结果暗示, CBF1-CBF3在调节冷响应基因的功能上具有冗余性(Park et al., 2015), 但它们之间实则存在差异.首先, 三者的表达模式有所差异: CBF1及CBF3主要在根、下胚轴及子叶中表达; 而CBF2则在下胚轴、子叶及第1、2对真叶中表达, 并不在根中表达(Novillo et al., 2007).当植株遭受低温胁迫时, CBF1及CBF3基因在叶片、萼片及角果中表达, 而CBF2还在茎中表达(Novillo et al., 2007).其次, 基因表达分析显示, CBF1及CBF3表达水平在低温诱导1个小时左右即达到峰值, 而CBF2则需要2小时才会达到峰值.低温条件下, CBF2还可以负反馈调节CBF1和CBF3的表达(Novillo et al., 2004), 如启动子区域插入T-DNA的cbf2突变体表现出抗冻的表型, 这可能是由于突变体中CBF1及CBF3基因过量表达造成的(Novillo et al., 2004, 2007).然而, Zhao等(2016)利用CRISPR/Cas9产生的cbf2突变体表现出冻敏感表型.目前, 猜测cbf突变体的以上表型差异可能是由于突变形式不同或植株生长状态不同等原因所致.由于CBF基因的启动子上没有CRT/DRE作用元件, 因此CBF2对CBF1及CBF3的转录调控可能不是直接的, 这其中的分子机制有待进一步研究.CBF1及CBF3的RNAi植株以及CBF1、CBF3的antisense植株中, CBF2的表达量并没有变化(Novillo et al., 2007).最近, Jia等(2016)研究表明, 利用CRISPR/Cas9产生的cbf1/cbf3双突变体在冷驯化后也具有敏感表型.这些结果暗示, CBF1和CBF3并不能调控CBF2基因的表达.有趣的是, 朱健康实验室利用CRISPR/Cas9技术获得的cbf1/cbf3双突变体中, CBF2的表达有2倍左右的上调, 并且在冷驯化后具有显著的抗冻表型(Zhao et al., 2016).因此, CBF1-CBF3相互的调控关系仍有待进一步研究.虽然以上2项研究中, cbf单突变体和双突变体的抗冻表型及基因表达水平有所不同, 但是cbf1/cbf2/cbf3三突变体的表型非常一致, 均是在冷驯化后产生极度冻敏感的表型(Jia et al., 2016; Zhao et al., 2016).与cbf1/cbf3双突变体的冷驯化表型相比可以得出结论, 在冷驯化后的植物抗冻性中, 相较于CBF1及CBF3, CBF2发挥更重要的作用(Zhao et al., 2016). ...
2 2017
... 除了ICE家族转录因子, 钙信号通路的重要组分CAMTA3 (calmodulin-binding transcription activator 3)也被发现参与CBF基因表达调控.Thomashow实验室通过鉴定冷诱导相关的顺式作用元件, 发现CBF2基因的启动子含有7个保守的CM (conserved motif)基序参与CBF2转录活性调控.进一步研究发现钙信号途径的转录因子CAMTA3可以通过与CM2位点结合, 正调控CBF1与CBF2的表达(Doherty et al., 2009).CAMTA1-3的不同组合双突变体在冷驯化前后均表现出冻敏感表型, 且驯化后的表型更明显.同时突变体中CBF1、CBF2、CBF3及下游冷相关基因的表达均有不同程度的下调, 说明这类转录因子共同参与CBF介导的植物抗冻性调控(Doherty et al., 2009; Kim et al., 2013).最近, Yamaguchi-Shinozaki研究组利用不同的camta突变体, 系统研究了CAM- TA蛋白对CBF的转录调控, 发现在迅速降温(10分钟之内从22°C降到4°C)和缓慢降温(60分钟内从22°C降到4°C)这2种过程中可能存在不同的调控机制(Kid- okoro et al., 2017).CAMTA3和CAMTA5在迅速降温过程中调控CBF的表达, 但在缓慢降温过程中则不起作用, 暗示这2种不同的降温过程可能存在不同的低温调控机制(Kidokoro et al., 2017). ... ... 的表达, 但在缓慢降温过程中则不起作用, 暗示这2种不同的降温过程可能存在不同的低温调控机制(Kidokoro et al., 2017). ...
1 2017
... 除了各种正调控因子调控CBF基因的转录水平, 许多负调节因子也参与对CBF基因的精细调控.MYB15是第1个被发现的CBF基因负调节因子.它编码1个R2R3类MYB转录因子, 结合在CBF3的MYB结合位点.进一步研究发现, MYB15与ICE1相互作用, 共同调控CBF3的表达.突变体中CBF3表达量升高, 植株表现出抗冻表型, 同时低温可以诱导MYB15的表达水平, 说明对CBF3的表达调控可能存在负反馈调节机制(Agarwal et al., 2006).近期的研究结果表明, MYB15的第168位Ser可以被MPK6磷酸化, 从而降低MYB15与CBF3启动子的结合能力, 将该Ser突变成Ala可以增强MYB15对CBF3的抑制.同时过量表达磷酸化位点失活形式的MYB15可使植株体内的CBF3表达水平显著降低, 其抗冻性强于MYB15过表达植株.以上结果表明, MYB15对CBF3的转录调节受到MPK6的磷酸化调控(Kim et al., 2017).目前发现MYB15可以与ICE1相互作用并调控其转录活性(Agarwal et al., 2006), 暗示转录调节子之间存在复杂的调控机制. ...
1 2013
... 除了ICE家族转录因子, 钙信号通路的重要组分CAMTA3 (calmodulin-binding transcription activator 3)也被发现参与CBF基因表达调控.Thomashow实验室通过鉴定冷诱导相关的顺式作用元件, 发现CBF2基因的启动子含有7个保守的CM (conserved motif)基序参与CBF2转录活性调控.进一步研究发现钙信号途径的转录因子CAMTA3可以通过与CM2位点结合, 正调控CBF1与CBF2的表达(Doherty et al., 2009).CAMTA1-3的不同组合双突变体在冷驯化前后均表现出冻敏感表型, 且驯化后的表型更明显.同时突变体中CBF1、CBF2、CBF3及下游冷相关基因的表达均有不同程度的下调, 说明这类转录因子共同参与CBF介导的植物抗冻性调控(Doherty et al., 2009; Kim et al., 2013).最近, Yamaguchi-Shinozaki研究组利用不同的camta突变体, 系统研究了CAM- TA蛋白对CBF的转录调控, 发现在迅速降温(10分钟之内从22°C降到4°C)和缓慢降温(60分钟内从22°C降到4°C)这2种过程中可能存在不同的调控机制(Kid- okoro et al., 2017).CAMTA3和CAMTA5在迅速降温过程中调控CBF的表达, 但在缓慢降温过程中则不起作用, 暗示这2种不同的降温过程可能存在不同的低温调控机制(Kidokoro et al., 2017). ...
1 2005
... 第1个被鉴定的同时也是研究得最深入的CBF冷响应正调节因子是bHLH类转录因子ICE1 (inducer of CBF expression 1) (Chinnusamy et al., 2003).2003年, 朱健康实验室利用EMS诱变含有ProCBF3:LUC的拟南芥转基因植株, 获得了ice1突变体, 并成功克隆到ICE1基因(Chinnusamy et al., 2003).ICE1编码1个MYC类bHLH家族转录因子, 与野生型相比, ice1突变体植株矮小, 生长发育缓慢, 体内CBF3基因的冷诱导情况被严重抑制, 且抗冻性大幅降低.这些结果表明, ICE1是低温信号途径中的正调控因子(Chinnusamy et al., 2003; Lee et al., 2005).有趣的是, ICE1特异性调节CBF3基因表达, ice1突变体中CBF1及CBF2基因的冷诱导表达下调十分微弱且后期没有影响, 说明ICE1的调节具有特异性.这可能与CBF基因启动子上的MYC结合位点的数目有关(CBF3启动子有5个结合位点, CBF1及CBF2启动子各有1个结合位点).ICE1特异性结合在CBF3启动子的MYC结合位点CANNTG (Meshi and Iwabuchi, 1995), 正调控CBF3基因表达.过表达ICE1可以明显增强植株的抗冻能力(Chinnusamy et al., 2003).最近在水稻、玉米及番茄的研究中发现, ICE1均可以正调控植物的耐寒性, 将这些物种中的ICE1蛋白在拟南芥中过表达均可增强植株的抗冻性, 说明ICE1在低温信号途径中的功能非常保守(Nosenko et al., 2016; Deng et al., 2017; Lu et al., 2017).ICE2作为ICE1的同源基因, 也参与调控植物的抗冻性.过表达ICE2可以显著提高植物的抗冻性, 并且植物体内的CBF1基因也被诱导表达, 暗示ICE2作用在CBF1的上游(Fursova et al., 2009). ...
2 2012
... 除了节律可调控植物对低温的响应, 光信号与光周期也被发现参与植物的抗冻性调节(Franklin and Whitelam, 2007; Lee and Thomashow, 2012).当植物生长在较低温度(16°C)且红光与远红光比(R/FR)降低时, 植物体内的CBF基因节律性表达增强, COR基因表达上调, 使植株产生更强的抗冻性, 这与红光及远红光受体光敏色素有关, 暗示环境温度可通过光敏色素调控CBF基因的节律性及其下游基因的表达(Franklin and Whitelam, 2007).与长日照相比, 生长在短日照下的野生型植株表现出更强的抗冻性, 这可能与短日照下植株中的CBF表达倍数更高有关.进一步研究发现, 长日照下, 2个光受体结合蛋白PIF4和PIF7蛋白水平增加, 它们通过直接结合在CBF3的G-box及E-box区, 负调控CBF的表达.CBF下游靶基因COR15a和Gols3的表达水平同样受到抑制, 因此造成植物抗冻性减弱(Lee and Thomashow, 2012).PIF3蛋白在黑暗时活性增强, 抑制植物的光形态建成(Ni et al., 1998; Leivar et al., 2008; Leivar and Monte, 2014).光照射下, 光敏色素与PIF蛋白相互作用, 促进PIF蛋白降解(Ni et al., 2014).PIF3可以被PRRK蛋白磷酸化并通过LRB Cullin 3 E3泛素连接酶降解(Ni et al., 2014, 2017).本实验室的最新研究表明, 乙烯信号途径的E3泛素连接酶EBF1和EBF2可以通过与PIF3相互作用, 使其经由26S蛋白酶体途径降解(Jiang et al., 2017).PIF3直接结合在CBF基因的启动子区, 负调控其表达, 是植物抗冻性的负调控因子.低温及黑暗条件下, EBF蛋白降解(Shi et al., 2012), 导致PIF3蛋白积累, 从而调控CBF基因的表达(Jiang et al., 2017).以上研究结果暗示, 光和温度对植物冷驯化过程的影响密不可分, PIF作为CBF重要的负调控因子, 平衡植物的抗冻性和生长发育过程. ... ... 的表达水平同样受到抑制, 因此造成植物抗冻性减弱(Lee and Thomashow, 2012).PIF3蛋白在黑暗时活性增强, 抑制植物的光形态建成(Ni et al., 1998; Leivar et al., 2008; Leivar and Monte, 2014).光照射下, 光敏色素与PIF蛋白相互作用, 促进PIF蛋白降解(Ni et al., 2014).PIF3可以被PRRK蛋白磷酸化并通过LRB Cullin 3 E3泛素连接酶降解(Ni et al., 2014, 2017).本实验室的最新研究表明, 乙烯信号途径的E3泛素连接酶EBF1和EBF2可以通过与PIF3相互作用, 使其经由26S蛋白酶体途径降解(Jiang et al., 2017).PIF3直接结合在CBF基因的启动子区, 负调控其表达, 是植物抗冻性的负调控因子.低温及黑暗条件下, EBF蛋白降解(Shi et al., 2012), 导致PIF3蛋白积累, 从而调控CBF基因的表达(Jiang et al., 2017).以上研究结果暗示, 光和温度对植物冷驯化过程的影响密不可分, PIF作为CBF重要的负调控因子, 平衡植物的抗冻性和生长发育过程. ...
1 2016
... 另一个非常值得关注的问题是作用于CBF最上游的植物低温感受器究竟是什么? 2015年, 种康课题组通过QTL发现水稻中的COLD1基因介导粳稻耐冷性(Ma et al., 2015).COLD1定位在细胞质膜和内质网膜上, 与拟南芥中G蛋白α亚基互作蛋白GTG1/2高度同源, 被认为是一个低温感受器.它通过与G蛋白α亚基互作, 影响G蛋白活性, 调控低温激活的Ca2+内流, 从而影响籼稻的耐冷性.基因表达分析显示COLD1的互补株系中CBF基因表达上调, 说明COLD1可能参与CBF的调控.该基因上的1个SNP是影响水稻耐冷的关键位点, 暗示COLD1基因在自然选择过程中的重要性(Ma et al., 2015).那么除此之外是否还有其它的低温感受器存在? 蓝藻中的温度感受器Hik33是一类组蛋白激酶(Zabulon et al., 2007; Shimura et al., 2012).植物中的组蛋白激酶作为激素受体发挥重要作用, 它们是否也是低温的感受器? 还有研究表明光受体phyB作为温度感受器调控植物对室温环境温度的感受(Jung et al., 2016; Legris et al., 2016), 但其是否参与低温的感受仍不清楚, 这些问题都有待进一步验证. ...
1 2014
... 除了节律可调控植物对低温的响应, 光信号与光周期也被发现参与植物的抗冻性调节(Franklin and Whitelam, 2007; Lee and Thomashow, 2012).当植物生长在较低温度(16°C)且红光与远红光比(R/FR)降低时, 植物体内的CBF基因节律性表达增强, COR基因表达上调, 使植株产生更强的抗冻性, 这与红光及远红光受体光敏色素有关, 暗示环境温度可通过光敏色素调控CBF基因的节律性及其下游基因的表达(Franklin and Whitelam, 2007).与长日照相比, 生长在短日照下的野生型植株表现出更强的抗冻性, 这可能与短日照下植株中的CBF表达倍数更高有关.进一步研究发现, 长日照下, 2个光受体结合蛋白PIF4和PIF7蛋白水平增加, 它们通过直接结合在CBF3的G-box及E-box区, 负调控CBF的表达.CBF下游靶基因COR15a和Gols3的表达水平同样受到抑制, 因此造成植物抗冻性减弱(Lee and Thomashow, 2012).PIF3蛋白在黑暗时活性增强, 抑制植物的光形态建成(Ni et al., 1998; Leivar et al., 2008; Leivar and Monte, 2014).光照射下, 光敏色素与PIF蛋白相互作用, 促进PIF蛋白降解(Ni et al., 2014).PIF3可以被PRRK蛋白磷酸化并通过LRB Cullin 3 E3泛素连接酶降解(Ni et al., 2014, 2017).本实验室的最新研究表明, 乙烯信号途径的E3泛素连接酶EBF1和EBF2可以通过与PIF3相互作用, 使其经由26S蛋白酶体途径降解(Jiang et al., 2017).PIF3直接结合在CBF基因的启动子区, 负调控其表达, 是植物抗冻性的负调控因子.低温及黑暗条件下, EBF蛋白降解(Shi et al., 2012), 导致PIF3蛋白积累, 从而调控CBF基因的表达(Jiang et al., 2017).以上研究结果暗示, 光和温度对植物冷驯化过程的影响密不可分, PIF作为CBF重要的负调控因子, 平衡植物的抗冻性和生长发育过程. ...
1 2008
... 除了节律可调控植物对低温的响应, 光信号与光周期也被发现参与植物的抗冻性调节(Franklin and Whitelam, 2007; Lee and Thomashow, 2012).当植物生长在较低温度(16°C)且红光与远红光比(R/FR)降低时, 植物体内的CBF基因节律性表达增强, COR基因表达上调, 使植株产生更强的抗冻性, 这与红光及远红光受体光敏色素有关, 暗示环境温度可通过光敏色素调控CBF基因的节律性及其下游基因的表达(Franklin and Whitelam, 2007).与长日照相比, 生长在短日照下的野生型植株表现出更强的抗冻性, 这可能与短日照下植株中的CBF表达倍数更高有关.进一步研究发现, 长日照下, 2个光受体结合蛋白PIF4和PIF7蛋白水平增加, 它们通过直接结合在CBF3的G-box及E-box区, 负调控CBF的表达.CBF下游靶基因COR15a和Gols3的表达水平同样受到抑制, 因此造成植物抗冻性减弱(Lee and Thomashow, 2012).PIF3蛋白在黑暗时活性增强, 抑制植物的光形态建成(Ni et al., 1998; Leivar et al., 2008; Leivar and Monte, 2014).光照射下, 光敏色素与PIF蛋白相互作用, 促进PIF蛋白降解(Ni et al., 2014).PIF3可以被PRRK蛋白磷酸化并通过LRB Cullin 3 E3泛素连接酶降解(Ni et al., 2014, 2017).本实验室的最新研究表明, 乙烯信号途径的E3泛素连接酶EBF1和EBF2可以通过与PIF3相互作用, 使其经由26S蛋白酶体途径降解(Jiang et al., 2017).PIF3直接结合在CBF基因的启动子区, 负调控其表达, 是植物抗冻性的负调控因子.低温及黑暗条件下, EBF蛋白降解(Shi et al., 2012), 导致PIF3蛋白积累, 从而调控CBF基因的表达(Jiang et al., 2017).以上研究结果暗示, 光和温度对植物冷驯化过程的影响密不可分, PIF作为CBF重要的负调控因子, 平衡植物的抗冻性和生长发育过程. ...
1 2017
... ICE1作为重要的CBF调节因子, 自身也被很多组分精细调控.目前已知的对ICE1的翻译后修饰包括HOS1 (high osmotic expression 1)介导的泛素化、SIZ1 (SAP and Miz 1)介导的SUMO化以及OST1 (open stomata 1)介导的磷酸化等, 这些修饰通过调节ICE1的蛋白水平或转录水平参与调控冷信号途径.同时一些转录抑制子(MYB15和JAZ)还可以与ICE1相互作用, 从而调节它的转录活性.HOS1与ICE1相互作用, 泛素化ICE1蛋白, 使其通过26S蛋白酶体途径进行降解(Dong et al., 2006).HOS1过表达植株中CBF3基因表达水平下调, 植株表现出冻敏感表型(Dong et al., 2006).ICE1还受到另一种E3蛋白SIZ1的SUMO化调控(Miura et al., 2007).SIZ1使ICE1蛋白SUMO化, 并减弱ICE1的泛素化, 从而维持ICE1蛋白的稳定性.siz1突变体中CBF3基因表达水平下调, 植株呈冻敏感表型(Miura et al., 2007).JA信号途径的负调节因子JAZ1 (jasmonate ZIM-domain)与JAZ4通过与ICE1蛋白具有bHLH结构域的C端相互作用, 抑制ICE1的转录活性, 从而参与对低温信号途径的调控(Hu et al., 2013).与之相对应, 过表达JAZ1及JAZ4的转基因植株, 以及JA合成途径及信号途径中一些组分的突变体均表现出低温敏感的表型(Hu et al., 2013).本实验室研究表明, 低温可以激活ABA信号途径中的重要激酶OST1, 使其磷酸化ICE1第278位Ser, 正调控ICE1蛋白的稳定性及转录活性, 从而促进下游CBF基因的表达(Ding et al., 2015).OST1对ICE1的磷酸化作用还可以抑制其与HOS1的互作, 从而抑制HOS1对ICE1的降解.以上结果说明OST1作为蛋白激酶, 在低温信号途径中起关键正调控作用(Ding et al., 2015).除此之外, 本实验室及朱健康研究组同时发现, 低温可以激活丝裂原活化蛋白激酶MPK3及MPK6, 它们通过磷酸化ICE1 (磷酸化位点与OST1对ICE1的磷酸化位点不同), 抑制ICE1蛋白的稳定性和转录活性, 从而负调控CBF基因表达及植物的抗冻性(Li et al., 2017a; Zhao et al., 2017).这些结果说明, ICE1作为重要的低温信号途径的转录因子, 被多种调节子不同程度地调控, 从而使植物更好地应对低温胁迫, 做出精细的应答反应. ...
3 2017
... 一系列激素信号途径中的调节组分被证明也会直接或间接参与CBF的转录调控.本实验室最新研究表明, BR信号途径的关键调节因子BZR1 (brassinazole-resistant 1)及其同源蛋白BES1 (BRI1-EMS- suppressor 1)通过结合CBF1与CBF2启动子上的E-box及BRRE结合位点, 正调控二者的表达(Li et al., 2017b).BZR1和BES1都是bHLH类转录因子, 在BR信号途径中起正调控作用(He et al., 2005; Yin et al., 2005), 它们的功能获得型突变体表现出强烈的抗冻表型(Li et al., 2017b).另一个BR信号途径的转录因子CESTA直接结合所有CBF启动子, 并组成性激活CBF及下游COR基因表达, 正调控植物的抗冻性(Eremina et al., 2016).进一步研究发现, 低温可以诱导非磷酸化形式的BZR1蛋白积累, 进而调控其磷酸化的蛋白激酶BIN2 (brassinosteroid insensitive 2)也作为负调节子参与植物的抗冻性调控.转录组分析数据表明, BZR1除了直接调节CBF基因表达, 还参与正向及负向调控一系列不依赖CBF的冷诱导基因的表达, 说明BZR1作为重要的调节因子, 在低温信号途径的精细调控中可能起到不同的关键作用, 而这其中的分子机制还有待进一步研究(Li et al., 2017b). ... ... ), 它们的功能获得型突变体表现出强烈的抗冻表型(Li et al., 2017b).另一个BR信号途径的转录因子CESTA直接结合所有CBF启动子, 并组成性激活CBF及下游COR基因表达, 正调控植物的抗冻性(Eremina et al., 2016).进一步研究发现, 低温可以诱导非磷酸化形式的BZR1蛋白积累, 进而调控其磷酸化的蛋白激酶BIN2 (brassinosteroid insensitive 2)也作为负调节子参与植物的抗冻性调控.转录组分析数据表明, BZR1除了直接调节CBF基因表达, 还参与正向及负向调控一系列不依赖CBF的冷诱导基因的表达, 说明BZR1作为重要的调节因子, 在低温信号途径的精细调控中可能起到不同的关键作用, 而这其中的分子机制还有待进一步研究(Li et al., 2017b). ... ... 的冷诱导基因的表达, 说明BZR1作为重要的调节因子, 在低温信号途径的精细调控中可能起到不同的关键作用, 而这其中的分子机制还有待进一步研究(Li et al., 2017b). ...
4 1998
... 在拟南芥(Arabidopsis thaliana)基因组中存在3个CBF基因, 属于一类转录因子家族CBF/DREB1 (de- hydration-responsive element-binding factors 1)基因.CBF家族成员串联排列在拟南芥第4条染色体上, 分别命名为CBF1 (DREB1B)、CBF2 (DREB1C)和CBF3 (DREB1A) (Gilmour et al., 1998; Liu et al., 1998).1997-1998年, Thomashow等利用酵母单杂交等技术相继鉴定到了CBF1-CBF3 (Stockinger et al., 1997; Gilmour et al., 1998; Liu et al., 1998), 它们可以与一段保守的CRT/DRE (C-repeat/dehydration response element)调控元件CCGAC结合(Baker et al., 1994), 该元件多出现在冷诱导COR (Cold- regulated)基因的启动子区域(Medina et al., 2011).氨基酸序列比对结果显示, CBF1-CBF3三者之间具有很高的相似性(>85%), 暗示它们可能起源于同一个基因(Gilmour et al., 1998; Medina et al., 1999).过量表达CBF1、CBF2及CBF3均能大幅提高植株的抗冻性, 并显著诱导植株体内COR基因的表达(Liu et al., 1998). ... ... ; Liu et al., 1998), 它们可以与一段保守的CRT/DRE (C-repeat/dehydration response element)调控元件CCGAC结合(Baker et al., 1994), 该元件多出现在冷诱导COR (Cold- regulated)基因的启动子区域(Medina et al., 2011).氨基酸序列比对结果显示, CBF1-CBF3三者之间具有很高的相似性(>85%), 暗示它们可能起源于同一个基因(Gilmour et al., 1998; Medina et al., 1999).过量表达CBF1、CBF2及CBF3均能大幅提高植株的抗冻性, 并显著诱导植株体内COR基因的表达(Liu et al., 1998). ... ... 基因的表达(Liu et al., 1998). ... ... 遗传分析表明CBF在低温信号途径中起关键作用.例如, 过表达CBF1-3均使拟南芥植株的抗冻性明显增强.进一步检测植物体内的下游冷响应基因, 发现约100个COR基因被组成型诱导, 从而使未经冷驯化的植株也能获得抗冻性(Gilmour et al., 1998; Jaglo- Ottosen et al., 1998; Liu et al., 1998; Kasuga et al., 1999; Gilmour et al., 2004).与野生型相比, CBF1及CBF3敲减拟南芥植株的抗冻性降低约60% (Novillo et al., 2007).在拟南芥中过表达CBF2的DNA结合域形成的dominant negative转基因植株中, CBF2可以结合在CRT/DRE作用位点却不能激活下游基因, 从而使植株呈现冻敏感表型(Park et al., 2015).为了进一步探究CBF1-CBF3的功能, 本实验室和上海植物逆境中心朱健康实验室分别利用CRISPR/Cas9技术获得了cbf1/cbf2/cbf3三突变体(Jia et al., 2016; Zhao et al., 2016).与野生型相比, 三突变体在非冷驯化时没有或具有轻微冻敏感表型, 而在冷驯化后表现出强烈的冻敏感表型.对突变体进行RNA-seq分析, 显示CBF突变影响了全转录组10%-20%的COR基因表达(Jia et al., 2016; Zhao et al., 2016).这些结果表明, CBF1- CBF3在低温信号途径中发挥重要的调控作用. ...
1 2017
... 除了转录水平的调控, CBF蛋白还存在翻译后修饰.本实验室利用反向筛选鉴定到1个CBF的上游负调节子CRPK1 (cold-responsive protein kinase 1).CRPK1是定位在细胞膜的类受体激酶, 低温直接激活其激酶活性, 激活的CRPK1通过磷酸化细胞质中的14-3-3蛋白, 使其从细胞质进入细胞核, 进一步与CBF1及CBF3相互作用, 参与CBF蛋白的泛素化降解, 从而负调控植物的抗冻性(Liu et al., 2017).这一研究阐明了低温通过调控蛋白激酶将信号从细胞膜传递到细胞核的分子机制, 首次揭示了CBF的翻译后水平修饰调控机制, 为CBF的调控机制研究开辟了新的方向. ...
1 2017
... 第1个被鉴定的同时也是研究得最深入的CBF冷响应正调节因子是bHLH类转录因子ICE1 (inducer of CBF expression 1) (Chinnusamy et al., 2003).2003年, 朱健康实验室利用EMS诱变含有ProCBF3:LUC的拟南芥转基因植株, 获得了ice1突变体, 并成功克隆到ICE1基因(Chinnusamy et al., 2003).ICE1编码1个MYC类bHLH家族转录因子, 与野生型相比, ice1突变体植株矮小, 生长发育缓慢, 体内CBF3基因的冷诱导情况被严重抑制, 且抗冻性大幅降低.这些结果表明, ICE1是低温信号途径中的正调控因子(Chinnusamy et al., 2003; Lee et al., 2005).有趣的是, ICE1特异性调节CBF3基因表达, ice1突变体中CBF1及CBF2基因的冷诱导表达下调十分微弱且后期没有影响, 说明ICE1的调节具有特异性.这可能与CBF基因启动子上的MYC结合位点的数目有关(CBF3启动子有5个结合位点, CBF1及CBF2启动子各有1个结合位点).ICE1特异性结合在CBF3启动子的MYC结合位点CANNTG (Meshi and Iwabuchi, 1995), 正调控CBF3基因表达.过表达ICE1可以明显增强植株的抗冻能力(Chinnusamy et al., 2003).最近在水稻、玉米及番茄的研究中发现, ICE1均可以正调控植物的耐寒性, 将这些物种中的ICE1蛋白在拟南芥中过表达均可增强植株的抗冻性, 说明ICE1在低温信号途径中的功能非常保守(Nosenko et al., 2016; Deng et al., 2017; Lu et al., 2017).ICE2作为ICE1的同源基因, 也参与调控植物的抗冻性.过表达ICE2可以显著提高植物的抗冻性, 并且植物体内的CBF1基因也被诱导表达, 暗示ICE2作用在CBF1的上游(Fursova et al., 2009). ...
2 2015
... 另一个非常值得关注的问题是作用于CBF最上游的植物低温感受器究竟是什么? 2015年, 种康课题组通过QTL发现水稻中的COLD1基因介导粳稻耐冷性(Ma et al., 2015).COLD1定位在细胞质膜和内质网膜上, 与拟南芥中G蛋白α亚基互作蛋白GTG1/2高度同源, 被认为是一个低温感受器.它通过与G蛋白α亚基互作, 影响G蛋白活性, 调控低温激活的Ca2+内流, 从而影响籼稻的耐冷性.基因表达分析显示COLD1的互补株系中CBF基因表达上调, 说明COLD1可能参与CBF的调控.该基因上的1个SNP是影响水稻耐冷的关键位点, 暗示COLD1基因在自然选择过程中的重要性(Ma et al., 2015).那么除此之外是否还有其它的低温感受器存在? 蓝藻中的温度感受器Hik33是一类组蛋白激酶(Zabulon et al., 2007; Shimura et al., 2012).植物中的组蛋白激酶作为激素受体发挥重要作用, 它们是否也是低温的感受器? 还有研究表明光受体phyB作为温度感受器调控植物对室温环境温度的感受(Jung et al., 2016; Legris et al., 2016), 但其是否参与低温的感受仍不清楚, 这些问题都有待进一步验证. ... ... 基因在自然选择过程中的重要性(Ma et al., 2015).那么除此之外是否还有其它的低温感受器存在? 蓝藻中的温度感受器Hik33是一类组蛋白激酶(Zabulon et al., 2007; Shimura et al., 2012).植物中的组蛋白激酶作为激素受体发挥重要作用, 它们是否也是低温的感受器? 还有研究表明光受体phyB作为温度感受器调控植物对室温环境温度的感受(Jung et al., 2016; Legris et al., 2016), 但其是否参与低温的感受仍不清楚, 这些问题都有待进一步验证. ...
1 1999
... 在拟南芥(Arabidopsis thaliana)基因组中存在3个CBF基因, 属于一类转录因子家族CBF/DREB1 (de- hydration-responsive element-binding factors 1)基因.CBF家族成员串联排列在拟南芥第4条染色体上, 分别命名为CBF1 (DREB1B)、CBF2 (DREB1C)和CBF3 (DREB1A) (Gilmour et al., 1998; Liu et al., 1998).1997-1998年, Thomashow等利用酵母单杂交等技术相继鉴定到了CBF1-CBF3 (Stockinger et al., 1997; Gilmour et al., 1998; Liu et al., 1998), 它们可以与一段保守的CRT/DRE (C-repeat/dehydration response element)调控元件CCGAC结合(Baker et al., 1994), 该元件多出现在冷诱导COR (Cold- regulated)基因的启动子区域(Medina et al., 2011).氨基酸序列比对结果显示, CBF1-CBF3三者之间具有很高的相似性(>85%), 暗示它们可能起源于同一个基因(Gilmour et al., 1998; Medina et al., 1999).过量表达CBF1、CBF2及CBF3均能大幅提高植株的抗冻性, 并显著诱导植株体内COR基因的表达(Liu et al., 1998). ...
1 2011
... 在拟南芥(Arabidopsis thaliana)基因组中存在3个CBF基因, 属于一类转录因子家族CBF/DREB1 (de- hydration-responsive element-binding factors 1)基因.CBF家族成员串联排列在拟南芥第4条染色体上, 分别命名为CBF1 (DREB1B)、CBF2 (DREB1C)和CBF3 (DREB1A) (Gilmour et al., 1998; Liu et al., 1998).1997-1998年, Thomashow等利用酵母单杂交等技术相继鉴定到了CBF1-CBF3 (Stockinger et al., 1997; Gilmour et al., 1998; Liu et al., 1998), 它们可以与一段保守的CRT/DRE (C-repeat/dehydration response element)调控元件CCGAC结合(Baker et al., 1994), 该元件多出现在冷诱导COR (Cold- regulated)基因的启动子区域(Medina et al., 2011).氨基酸序列比对结果显示, CBF1-CBF3三者之间具有很高的相似性(>85%), 暗示它们可能起源于同一个基因(Gilmour et al., 1998; Medina et al., 1999).过量表达CBF1、CBF2及CBF3均能大幅提高植株的抗冻性, 并显著诱导植株体内COR基因的表达(Liu et al., 1998). ...
1 1995
... 第1个被鉴定的同时也是研究得最深入的CBF冷响应正调节因子是bHLH类转录因子ICE1 (inducer of CBF expression 1) (Chinnusamy et al., 2003).2003年, 朱健康实验室利用EMS诱变含有ProCBF3:LUC的拟南芥转基因植株, 获得了ice1突变体, 并成功克隆到ICE1基因(Chinnusamy et al., 2003).ICE1编码1个MYC类bHLH家族转录因子, 与野生型相比, ice1突变体植株矮小, 生长发育缓慢, 体内CBF3基因的冷诱导情况被严重抑制, 且抗冻性大幅降低.这些结果表明, ICE1是低温信号途径中的正调控因子(Chinnusamy et al., 2003; Lee et al., 2005).有趣的是, ICE1特异性调节CBF3基因表达, ice1突变体中CBF1及CBF2基因的冷诱导表达下调十分微弱且后期没有影响, 说明ICE1的调节具有特异性.这可能与CBF基因启动子上的MYC结合位点的数目有关(CBF3启动子有5个结合位点, CBF1及CBF2启动子各有1个结合位点).ICE1特异性结合在CBF3启动子的MYC结合位点CANNTG (Meshi and Iwabuchi, 1995), 正调控CBF3基因表达.过表达ICE1可以明显增强植株的抗冻能力(Chinnusamy et al., 2003).最近在水稻、玉米及番茄的研究中发现, ICE1均可以正调控植物的耐寒性, 将这些物种中的ICE1蛋白在拟南芥中过表达均可增强植株的抗冻性, 说明ICE1在低温信号途径中的功能非常保守(Nosenko et al., 2016; Deng et al., 2017; Lu et al., 2017).ICE2作为ICE1的同源基因, 也参与调控植物的抗冻性.过表达ICE2可以显著提高植物的抗冻性, 并且植物体内的CBF1基因也被诱导表达, 暗示ICE2作用在CBF1的上游(Fursova et al., 2009). ...
1 2009
... 植物的开花过程也受到低温调控, 低温可抑制开花而高温则促进开花(Blázquez et al., 2003).开花途径重要的调节因子SOC1 (suppressor of overexpression of constans 1)编码1个MADS类转录因子, 研究表明SOC1可以直接结合CBF启动子的CArG元件, 负调节CBF基因的表达(Seo et al., 2009).与此对应, soc1突变体也表现出明显的抗冻性, 说明SOC1是开花途径与低温信号途径相互作用的节点(Seo et al., 2009).自2000年以来, 不断有研究表明, CBF及其下游冷响应基因的表达存在节律现象(Har- mer et al., 2000; Bieniawska et al., 2008; Espinoza et al., 2008; Mikkelsen and Thomashow, 2009), 其基因表达在黎明后8小时达到峰值, 并在黎明后20小时达到低谷.多项研究表明, 节律可以同时正向及负向调控CBF基因的转录水平.节律中心调控因子包括MYB类转录因子CCA1 (circadian clock associated 1)与LHY (late elongated hypocotyl)以及PRR (pseudoresponse regulator)蛋白TOC1, 它们相互调控彼此的基因表达, 从而形成反馈环机制.三突变体prr5/prr7/prr9中CBF基因组成型高水平表达, 并表现出明显的抗冻表型, 暗示PRRs参与抑制CBF基因表达(Nakamichi et al., 2009, 2012).2011年, Thom- ashow实验室发现拟南芥中央振荡器因子CCA1及LHY可以正调控CBF的表达.CCA1及LHY均编码MYB类转录因子, 它们通过结合CBF1-CBF3基因启动子上的EE及CBS结合位点, 直接调控CBF基因表达.cca1/lhy双突变体中CBF基因表达水平大幅下调, 并且CBF基因表达的节律性也有所减弱(Dong et al., 2011).CBF下游调控基因COR15A、COR47及COR78表达水平也显著下调.双突变体在冷驯化前后均表现出敏感表型, 说明节律调控因子CCA1及LHY通过直接调控CBF的表达, 参与低温信号途径(Dong et al., 2011).进一步研究发现, CCA1的2个转录本CCA1α及CCA1β均参与低温信号途径.低温抑制CCA1β的表达, 而CCA1β通过与CCA1α相互作用, 抑制CCA1α的表达(Seo et al., 2012). ...
2 2007
... ICE1作为重要的CBF调节因子, 自身也被很多组分精细调控.目前已知的对ICE1的翻译后修饰包括HOS1 (high osmotic expression 1)介导的泛素化、SIZ1 (SAP and Miz 1)介导的SUMO化以及OST1 (open stomata 1)介导的磷酸化等, 这些修饰通过调节ICE1的蛋白水平或转录水平参与调控冷信号途径.同时一些转录抑制子(MYB15和JAZ)还可以与ICE1相互作用, 从而调节它的转录活性.HOS1与ICE1相互作用, 泛素化ICE1蛋白, 使其通过26S蛋白酶体途径进行降解(Dong et al., 2006).HOS1过表达植株中CBF3基因表达水平下调, 植株表现出冻敏感表型(Dong et al., 2006).ICE1还受到另一种E3蛋白SIZ1的SUMO化调控(Miura et al., 2007).SIZ1使ICE1蛋白SUMO化, 并减弱ICE1的泛素化, 从而维持ICE1蛋白的稳定性.siz1突变体中CBF3基因表达水平下调, 植株呈冻敏感表型(Miura et al., 2007).JA信号途径的负调节因子JAZ1 (jasmonate ZIM-domain)与JAZ4通过与ICE1蛋白具有bHLH结构域的C端相互作用, 抑制ICE1的转录活性, 从而参与对低温信号途径的调控(Hu et al., 2013).与之相对应, 过表达JAZ1及JAZ4的转基因植株, 以及JA合成途径及信号途径中一些组分的突变体均表现出低温敏感的表型(Hu et al., 2013).本实验室研究表明, 低温可以激活ABA信号途径中的重要激酶OST1, 使其磷酸化ICE1第278位Ser, 正调控ICE1蛋白的稳定性及转录活性, 从而促进下游CBF基因的表达(Ding et al., 2015).OST1对ICE1的磷酸化作用还可以抑制其与HOS1的互作, 从而抑制HOS1对ICE1的降解.以上结果说明OST1作为蛋白激酶, 在低温信号途径中起关键正调控作用(Ding et al., 2015).除此之外, 本实验室及朱健康研究组同时发现, 低温可以激活丝裂原活化蛋白激酶MPK3及MPK6, 它们通过磷酸化ICE1 (磷酸化位点与OST1对ICE1的磷酸化位点不同), 抑制ICE1蛋白的稳定性和转录活性, 从而负调控CBF基因表达及植物的抗冻性(Li et al., 2017a; Zhao et al., 2017).这些结果说明, ICE1作为重要的低温信号途径的转录因子, 被多种调节子不同程度地调控, 从而使植物更好地应对低温胁迫, 做出精细的应答反应. ... ... 基因表达水平下调, 植株呈冻敏感表型(Miura et al., 2007).JA信号途径的负调节因子JAZ1 (jasmonate ZIM-domain)与JAZ4通过与ICE1蛋白具有bHLH结构域的C端相互作用, 抑制ICE1的转录活性, 从而参与对低温信号途径的调控(Hu et al., 2013).与之相对应, 过表达JAZ1及JAZ4的转基因植株, 以及JA合成途径及信号途径中一些组分的突变体均表现出低温敏感的表型(Hu et al., 2013).本实验室研究表明, 低温可以激活ABA信号途径中的重要激酶OST1, 使其磷酸化ICE1第278位Ser, 正调控ICE1蛋白的稳定性及转录活性, 从而促进下游CBF基因的表达(Ding et al., 2015).OST1对ICE1的磷酸化作用还可以抑制其与HOS1的互作, 从而抑制HOS1对ICE1的降解.以上结果说明OST1作为蛋白激酶, 在低温信号途径中起关键正调控作用(Ding et al., 2015).除此之外, 本实验室及朱健康研究组同时发现, 低温可以激活丝裂原活化蛋白激酶MPK3及MPK6, 它们通过磷酸化ICE1 (磷酸化位点与OST1对ICE1的磷酸化位点不同), 抑制ICE1蛋白的稳定性和转录活性, 从而负调控CBF基因表达及植物的抗冻性(Li et al., 2017a; Zhao et al., 2017).这些结果说明, ICE1作为重要的低温信号途径的转录因子, 被多种调节子不同程度地调控, 从而使植物更好地应对低温胁迫, 做出精细的应答反应. ...
1 2012
... 植物的开花过程也受到低温调控, 低温可抑制开花而高温则促进开花(Blázquez et al., 2003).开花途径重要的调节因子SOC1 (suppressor of overexpression of constans 1)编码1个MADS类转录因子, 研究表明SOC1可以直接结合CBF启动子的CArG元件, 负调节CBF基因的表达(Seo et al., 2009).与此对应, soc1突变体也表现出明显的抗冻性, 说明SOC1是开花途径与低温信号途径相互作用的节点(Seo et al., 2009).自2000年以来, 不断有研究表明, CBF及其下游冷响应基因的表达存在节律现象(Har- mer et al., 2000; Bieniawska et al., 2008; Espinoza et al., 2008; Mikkelsen and Thomashow, 2009), 其基因表达在黎明后8小时达到峰值, 并在黎明后20小时达到低谷.多项研究表明, 节律可以同时正向及负向调控CBF基因的转录水平.节律中心调控因子包括MYB类转录因子CCA1 (circadian clock associated 1)与LHY (late elongated hypocotyl)以及PRR (pseudoresponse regulator)蛋白TOC1, 它们相互调控彼此的基因表达, 从而形成反馈环机制.三突变体prr5/prr7/prr9中CBF基因组成型高水平表达, 并表现出明显的抗冻表型, 暗示PRRs参与抑制CBF基因表达(Nakamichi et al., 2009, 2012).2011年, Thom- ashow实验室发现拟南芥中央振荡器因子CCA1及LHY可以正调控CBF的表达.CCA1及LHY均编码MYB类转录因子, 它们通过结合CBF1-CBF3基因启动子上的EE及CBS结合位点, 直接调控CBF基因表达.cca1/lhy双突变体中CBF基因表达水平大幅下调, 并且CBF基因表达的节律性也有所减弱(Dong et al., 2011).CBF下游调控基因COR15A、COR47及COR78表达水平也显著下调.双突变体在冷驯化前后均表现出敏感表型, 说明节律调控因子CCA1及LHY通过直接调控CBF的表达, 参与低温信号途径(Dong et al., 2011).进一步研究发现, CCA1的2个转录本CCA1α及CCA1β均参与低温信号途径.低温抑制CCA1β的表达, 而CCA1β通过与CCA1α相互作用, 抑制CCA1α的表达(Seo et al., 2012). ...
1 2009
... 植物的开花过程也受到低温调控, 低温可抑制开花而高温则促进开花(Blázquez et al., 2003).开花途径重要的调节因子SOC1 (suppressor of overexpression of constans 1)编码1个MADS类转录因子, 研究表明SOC1可以直接结合CBF启动子的CArG元件, 负调节CBF基因的表达(Seo et al., 2009).与此对应, soc1突变体也表现出明显的抗冻性, 说明SOC1是开花途径与低温信号途径相互作用的节点(Seo et al., 2009).自2000年以来, 不断有研究表明, CBF及其下游冷响应基因的表达存在节律现象(Har- mer et al., 2000; Bieniawska et al., 2008; Espinoza et al., 2008; Mikkelsen and Thomashow, 2009), 其基因表达在黎明后8小时达到峰值, 并在黎明后20小时达到低谷.多项研究表明, 节律可以同时正向及负向调控CBF基因的转录水平.节律中心调控因子包括MYB类转录因子CCA1 (circadian clock associated 1)与LHY (late elongated hypocotyl)以及PRR (pseudoresponse regulator)蛋白TOC1, 它们相互调控彼此的基因表达, 从而形成反馈环机制.三突变体prr5/prr7/prr9中CBF基因组成型高水平表达, 并表现出明显的抗冻表型, 暗示PRRs参与抑制CBF基因表达(Nakamichi et al., 2009, 2012).2011年, Thom- ashow实验室发现拟南芥中央振荡器因子CCA1及LHY可以正调控CBF的表达.CCA1及LHY均编码MYB类转录因子, 它们通过结合CBF1-CBF3基因启动子上的EE及CBS结合位点, 直接调控CBF基因表达.cca1/lhy双突变体中CBF基因表达水平大幅下调, 并且CBF基因表达的节律性也有所减弱(Dong et al., 2011).CBF下游调控基因COR15A、COR47及COR78表达水平也显著下调.双突变体在冷驯化前后均表现出敏感表型, 说明节律调控因子CCA1及LHY通过直接调控CBF的表达, 参与低温信号途径(Dong et al., 2011).进一步研究发现, CCA1的2个转录本CCA1α及CCA1β均参与低温信号途径.低温抑制CCA1β的表达, 而CCA1β通过与CCA1α相互作用, 抑制CCA1α的表达(Seo et al., 2012). ...
1 1998
... 除了节律可调控植物对低温的响应, 光信号与光周期也被发现参与植物的抗冻性调节(Franklin and Whitelam, 2007; Lee and Thomashow, 2012).当植物生长在较低温度(16°C)且红光与远红光比(R/FR)降低时, 植物体内的CBF基因节律性表达增强, COR基因表达上调, 使植株产生更强的抗冻性, 这与红光及远红光受体光敏色素有关, 暗示环境温度可通过光敏色素调控CBF基因的节律性及其下游基因的表达(Franklin and Whitelam, 2007).与长日照相比, 生长在短日照下的野生型植株表现出更强的抗冻性, 这可能与短日照下植株中的CBF表达倍数更高有关.进一步研究发现, 长日照下, 2个光受体结合蛋白PIF4和PIF7蛋白水平增加, 它们通过直接结合在CBF3的G-box及E-box区, 负调控CBF的表达.CBF下游靶基因COR15a和Gols3的表达水平同样受到抑制, 因此造成植物抗冻性减弱(Lee and Thomashow, 2012).PIF3蛋白在黑暗时活性增强, 抑制植物的光形态建成(Ni et al., 1998; Leivar et al., 2008; Leivar and Monte, 2014).光照射下, 光敏色素与PIF蛋白相互作用, 促进PIF蛋白降解(Ni et al., 2014).PIF3可以被PRRK蛋白磷酸化并通过LRB Cullin 3 E3泛素连接酶降解(Ni et al., 2014, 2017).本实验室的最新研究表明, 乙烯信号途径的E3泛素连接酶EBF1和EBF2可以通过与PIF3相互作用, 使其经由26S蛋白酶体途径降解(Jiang et al., 2017).PIF3直接结合在CBF基因的启动子区, 负调控其表达, 是植物抗冻性的负调控因子.低温及黑暗条件下, EBF蛋白降解(Shi et al., 2012), 导致PIF3蛋白积累, 从而调控CBF基因的表达(Jiang et al., 2017).以上研究结果暗示, 光和温度对植物冷驯化过程的影响密不可分, PIF作为CBF重要的负调控因子, 平衡植物的抗冻性和生长发育过程. ...
1 2017
... 除了节律可调控植物对低温的响应, 光信号与光周期也被发现参与植物的抗冻性调节(Franklin and Whitelam, 2007; Lee and Thomashow, 2012).当植物生长在较低温度(16°C)且红光与远红光比(R/FR)降低时, 植物体内的CBF基因节律性表达增强, COR基因表达上调, 使植株产生更强的抗冻性, 这与红光及远红光受体光敏色素有关, 暗示环境温度可通过光敏色素调控CBF基因的节律性及其下游基因的表达(Franklin and Whitelam, 2007).与长日照相比, 生长在短日照下的野生型植株表现出更强的抗冻性, 这可能与短日照下植株中的CBF表达倍数更高有关.进一步研究发现, 长日照下, 2个光受体结合蛋白PIF4和PIF7蛋白水平增加, 它们通过直接结合在CBF3的G-box及E-box区, 负调控CBF的表达.CBF下游靶基因COR15a和Gols3的表达水平同样受到抑制, 因此造成植物抗冻性减弱(Lee and Thomashow, 2012).PIF3蛋白在黑暗时活性增强, 抑制植物的光形态建成(Ni et al., 1998; Leivar et al., 2008; Leivar and Monte, 2014).光照射下, 光敏色素与PIF蛋白相互作用, 促进PIF蛋白降解(Ni et al., 2014).PIF3可以被PRRK蛋白磷酸化并通过LRB Cullin 3 E3泛素连接酶降解(Ni et al., 2014, 2017).本实验室的最新研究表明, 乙烯信号途径的E3泛素连接酶EBF1和EBF2可以通过与PIF3相互作用, 使其经由26S蛋白酶体途径降解(Jiang et al., 2017).PIF3直接结合在CBF基因的启动子区, 负调控其表达, 是植物抗冻性的负调控因子.低温及黑暗条件下, EBF蛋白降解(Shi et al., 2012), 导致PIF3蛋白积累, 从而调控CBF基因的表达(Jiang et al., 2017).以上研究结果暗示, 光和温度对植物冷驯化过程的影响密不可分, PIF作为CBF重要的负调控因子, 平衡植物的抗冻性和生长发育过程. ...
2 2014
... 除了节律可调控植物对低温的响应, 光信号与光周期也被发现参与植物的抗冻性调节(Franklin and Whitelam, 2007; Lee and Thomashow, 2012).当植物生长在较低温度(16°C)且红光与远红光比(R/FR)降低时, 植物体内的CBF基因节律性表达增强, COR基因表达上调, 使植株产生更强的抗冻性, 这与红光及远红光受体光敏色素有关, 暗示环境温度可通过光敏色素调控CBF基因的节律性及其下游基因的表达(Franklin and Whitelam, 2007).与长日照相比, 生长在短日照下的野生型植株表现出更强的抗冻性, 这可能与短日照下植株中的CBF表达倍数更高有关.进一步研究发现, 长日照下, 2个光受体结合蛋白PIF4和PIF7蛋白水平增加, 它们通过直接结合在CBF3的G-box及E-box区, 负调控CBF的表达.CBF下游靶基因COR15a和Gols3的表达水平同样受到抑制, 因此造成植物抗冻性减弱(Lee and Thomashow, 2012).PIF3蛋白在黑暗时活性增强, 抑制植物的光形态建成(Ni et al., 1998; Leivar et al., 2008; Leivar and Monte, 2014).光照射下, 光敏色素与PIF蛋白相互作用, 促进PIF蛋白降解(Ni et al., 2014).PIF3可以被PRRK蛋白磷酸化并通过LRB Cullin 3 E3泛素连接酶降解(Ni et al., 2014, 2017).本实验室的最新研究表明, 乙烯信号途径的E3泛素连接酶EBF1和EBF2可以通过与PIF3相互作用, 使其经由26S蛋白酶体途径降解(Jiang et al., 2017).PIF3直接结合在CBF基因的启动子区, 负调控其表达, 是植物抗冻性的负调控因子.低温及黑暗条件下, EBF蛋白降解(Shi et al., 2012), 导致PIF3蛋白积累, 从而调控CBF基因的表达(Jiang et al., 2017).以上研究结果暗示, 光和温度对植物冷驯化过程的影响密不可分, PIF作为CBF重要的负调控因子, 平衡植物的抗冻性和生长发育过程. ... ... ).PIF3可以被PRRK蛋白磷酸化并通过LRB Cullin 3 E3泛素连接酶降解(Ni et al., 2014, 2017).本实验室的最新研究表明, 乙烯信号途径的E3泛素连接酶EBF1和EBF2可以通过与PIF3相互作用, 使其经由26S蛋白酶体途径降解(Jiang et al., 2017).PIF3直接结合在CBF基因的启动子区, 负调控其表达, 是植物抗冻性的负调控因子.低温及黑暗条件下, EBF蛋白降解(Shi et al., 2012), 导致PIF3蛋白积累, 从而调控CBF基因的表达(Jiang et al., 2017).以上研究结果暗示, 光和温度对植物冷驯化过程的影响密不可分, PIF作为CBF重要的负调控因子, 平衡植物的抗冻性和生长发育过程. ...
1 2016
... 第1个被鉴定的同时也是研究得最深入的CBF冷响应正调节因子是bHLH类转录因子ICE1 (inducer of CBF expression 1) (Chinnusamy et al., 2003).2003年, 朱健康实验室利用EMS诱变含有ProCBF3:LUC的拟南芥转基因植株, 获得了ice1突变体, 并成功克隆到ICE1基因(Chinnusamy et al., 2003).ICE1编码1个MYC类bHLH家族转录因子, 与野生型相比, ice1突变体植株矮小, 生长发育缓慢, 体内CBF3基因的冷诱导情况被严重抑制, 且抗冻性大幅降低.这些结果表明, ICE1是低温信号途径中的正调控因子(Chinnusamy et al., 2003; Lee et al., 2005).有趣的是, ICE1特异性调节CBF3基因表达, ice1突变体中CBF1及CBF2基因的冷诱导表达下调十分微弱且后期没有影响, 说明ICE1的调节具有特异性.这可能与CBF基因启动子上的MYC结合位点的数目有关(CBF3启动子有5个结合位点, CBF1及CBF2启动子各有1个结合位点).ICE1特异性结合在CBF3启动子的MYC结合位点CANNTG (Meshi and Iwabuchi, 1995), 正调控CBF3基因表达.过表达ICE1可以明显增强植株的抗冻能力(Chinnusamy et al., 2003).最近在水稻、玉米及番茄的研究中发现, ICE1均可以正调控植物的耐寒性, 将这些物种中的ICE1蛋白在拟南芥中过表达均可增强植株的抗冻性, 说明ICE1在低温信号途径中的功能非常保守(Nosenko et al., 2016; Deng et al., 2017; Lu et al., 2017).ICE2作为ICE1的同源基因, 也参与调控植物的抗冻性.过表达ICE2可以显著提高植物的抗冻性, 并且植物体内的CBF1基因也被诱导表达, 暗示ICE2作用在CBF1的上游(Fursova et al., 2009). ...
2 2004
... 截至目前, 在油菜(Brassica campestris)、小麦(Triticum aestivum)、黑麦(Secale cereale)、番茄(Lycopersicon esculentum)、水稻(Oryza sativa)及玉米(Zea mays)等植物中均鉴定到了CBF转录因子(Jaglo et al., 2001; Kasuga et al., 2004; Qin et al., 2004), 并且都具有冷诱导特性; 同时, 在其它物种中过表达拟南芥CBF也可以增强植物的抗冻性(Jaglo et al., 2001; Kasuga et al., 2004).在拟南芥中过表达玉米DREB1A也会产生类似的抗冻效果(Qin et al., 2004), 说明植物中CBF在低温信号途径中的作用十分保守.虽然一些研究结果暗示, CBF1-CBF3在调节冷响应基因的功能上具有冗余性(Park et al., 2015), 但它们之间实则存在差异.首先, 三者的表达模式有所差异: CBF1及CBF3主要在根、下胚轴及子叶中表达; 而CBF2则在下胚轴、子叶及第1、2对真叶中表达, 并不在根中表达(Novillo et al., 2007).当植株遭受低温胁迫时, CBF1及CBF3基因在叶片、萼片及角果中表达, 而CBF2还在茎中表达(Novillo et al., 2007).其次, 基因表达分析显示, CBF1及CBF3表达水平在低温诱导1个小时左右即达到峰值, 而CBF2则需要2小时才会达到峰值.低温条件下, CBF2还可以负反馈调节CBF1和CBF3的表达(Novillo et al., 2004), 如启动子区域插入T-DNA的cbf2突变体表现出抗冻的表型, 这可能是由于突变体中CBF1及CBF3基因过量表达造成的(Novillo et al., 2004, 2007).然而, Zhao等(2016)利用CRISPR/Cas9产生的cbf2突变体表现出冻敏感表型.目前, 猜测cbf突变体的以上表型差异可能是由于突变形式不同或植株生长状态不同等原因所致.由于CBF基因的启动子上没有CRT/DRE作用元件, 因此CBF2对CBF1及CBF3的转录调控可能不是直接的, 这其中的分子机制有待进一步研究.CBF1及CBF3的RNAi植株以及CBF1、CBF3的antisense植株中, CBF2的表达量并没有变化(Novillo et al., 2007).最近, Jia等(2016)研究表明, 利用CRISPR/Cas9产生的cbf1/cbf3双突变体在冷驯化后也具有敏感表型.这些结果暗示, CBF1和CBF3并不能调控CBF2基因的表达.有趣的是, 朱健康实验室利用CRISPR/Cas9技术获得的cbf1/cbf3双突变体中, CBF2的表达有2倍左右的上调, 并且在冷驯化后具有显著的抗冻表型(Zhao et al., 2016).因此, CBF1-CBF3相互的调控关系仍有待进一步研究.虽然以上2项研究中, cbf单突变体和双突变体的抗冻表型及基因表达水平有所不同, 但是cbf1/cbf2/cbf3三突变体的表型非常一致, 均是在冷驯化后产生极度冻敏感的表型(Jia et al., 2016; Zhao et al., 2016).与cbf1/cbf3双突变体的冷驯化表型相比可以得出结论, 在冷驯化后的植物抗冻性中, 相较于CBF1及CBF3, CBF2发挥更重要的作用(Zhao et al., 2016). ... ... 基因过量表达造成的(Novillo et al., 2004, 2007).然而, Zhao等(2016)利用CRISPR/Cas9产生的cbf2突变体表现出冻敏感表型.目前, 猜测cbf突变体的以上表型差异可能是由于突变形式不同或植株生长状态不同等原因所致.由于CBF基因的启动子上没有CRT/DRE作用元件, 因此CBF2对CBF1及CBF3的转录调控可能不是直接的, 这其中的分子机制有待进一步研究.CBF1及CBF3的RNAi植株以及CBF1、CBF3的antisense植株中, CBF2的表达量并没有变化(Novillo et al., 2007).最近, Jia等(2016)研究表明, 利用CRISPR/Cas9产生的cbf1/cbf3双突变体在冷驯化后也具有敏感表型.这些结果暗示, CBF1和CBF3并不能调控CBF2基因的表达.有趣的是, 朱健康实验室利用CRISPR/Cas9技术获得的cbf1/cbf3双突变体中, CBF2的表达有2倍左右的上调, 并且在冷驯化后具有显著的抗冻表型(Zhao et al., 2016).因此, CBF1-CBF3相互的调控关系仍有待进一步研究.虽然以上2项研究中, cbf单突变体和双突变体的抗冻表型及基因表达水平有所不同, 但是cbf1/cbf2/cbf3三突变体的表型非常一致, 均是在冷驯化后产生极度冻敏感的表型(Jia et al., 2016; Zhao et al., 2016).与cbf1/cbf3双突变体的冷驯化表型相比可以得出结论, 在冷驯化后的植物抗冻性中, 相较于CBF1及CBF3, CBF2发挥更重要的作用(Zhao et al., 2016). ...
5 2007
... 遗传分析表明CBF在低温信号途径中起关键作用.例如, 过表达CBF1-3均使拟南芥植株的抗冻性明显增强.进一步检测植物体内的下游冷响应基因, 发现约100个COR基因被组成型诱导, 从而使未经冷驯化的植株也能获得抗冻性(Gilmour et al., 1998; Jaglo- Ottosen et al., 1998; Liu et al., 1998; Kasuga et al., 1999; Gilmour et al., 2004).与野生型相比, CBF1及CBF3敲减拟南芥植株的抗冻性降低约60% (Novillo et al., 2007).在拟南芥中过表达CBF2的DNA结合域形成的dominant negative转基因植株中, CBF2可以结合在CRT/DRE作用位点却不能激活下游基因, 从而使植株呈现冻敏感表型(Park et al., 2015).为了进一步探究CBF1-CBF3的功能, 本实验室和上海植物逆境中心朱健康实验室分别利用CRISPR/Cas9技术获得了cbf1/cbf2/cbf3三突变体(Jia et al., 2016; Zhao et al., 2016).与野生型相比, 三突变体在非冷驯化时没有或具有轻微冻敏感表型, 而在冷驯化后表现出强烈的冻敏感表型.对突变体进行RNA-seq分析, 显示CBF突变影响了全转录组10%-20%的COR基因表达(Jia et al., 2016; Zhao et al., 2016).这些结果表明, CBF1- CBF3在低温信号途径中发挥重要的调控作用. ... ... 截至目前, 在油菜(Brassica campestris)、小麦(Triticum aestivum)、黑麦(Secale cereale)、番茄(Lycopersicon esculentum)、水稻(Oryza sativa)及玉米(Zea mays)等植物中均鉴定到了CBF转录因子(Jaglo et al., 2001; Kasuga et al., 2004; Qin et al., 2004), 并且都具有冷诱导特性; 同时, 在其它物种中过表达拟南芥CBF也可以增强植物的抗冻性(Jaglo et al., 2001; Kasuga et al., 2004).在拟南芥中过表达玉米DREB1A也会产生类似的抗冻效果(Qin et al., 2004), 说明植物中CBF在低温信号途径中的作用十分保守.虽然一些研究结果暗示, CBF1-CBF3在调节冷响应基因的功能上具有冗余性(Park et al., 2015), 但它们之间实则存在差异.首先, 三者的表达模式有所差异: CBF1及CBF3主要在根、下胚轴及子叶中表达; 而CBF2则在下胚轴、子叶及第1、2对真叶中表达, 并不在根中表达(Novillo et al., 2007).当植株遭受低温胁迫时, CBF1及CBF3基因在叶片、萼片及角果中表达, 而CBF2还在茎中表达(Novillo et al., 2007).其次, 基因表达分析显示, CBF1及CBF3表达水平在低温诱导1个小时左右即达到峰值, 而CBF2则需要2小时才会达到峰值.低温条件下, CBF2还可以负反馈调节CBF1和CBF3的表达(Novillo et al., 2004), 如启动子区域插入T-DNA的cbf2突变体表现出抗冻的表型, 这可能是由于突变体中CBF1及CBF3基因过量表达造成的(Novillo et al., 2004, 2007).然而, Zhao等(2016)利用CRISPR/Cas9产生的cbf2突变体表现出冻敏感表型.目前, 猜测cbf突变体的以上表型差异可能是由于突变形式不同或植株生长状态不同等原因所致.由于CBF基因的启动子上没有CRT/DRE作用元件, 因此CBF2对CBF1及CBF3的转录调控可能不是直接的, 这其中的分子机制有待进一步研究.CBF1及CBF3的RNAi植株以及CBF1、CBF3的antisense植株中, CBF2的表达量并没有变化(Novillo et al., 2007).最近, Jia等(2016)研究表明, 利用CRISPR/Cas9产生的cbf1/cbf3双突变体在冷驯化后也具有敏感表型.这些结果暗示, CBF1和CBF3并不能调控CBF2基因的表达.有趣的是, 朱健康实验室利用CRISPR/Cas9技术获得的cbf1/cbf3双突变体中, CBF2的表达有2倍左右的上调, 并且在冷驯化后具有显著的抗冻表型(Zhao et al., 2016).因此, CBF1-CBF3相互的调控关系仍有待进一步研究.虽然以上2项研究中, cbf单突变体和双突变体的抗冻表型及基因表达水平有所不同, 但是cbf1/cbf2/cbf3三突变体的表型非常一致, 均是在冷驯化后产生极度冻敏感的表型(Jia et al., 2016; Zhao et al., 2016).与cbf1/cbf3双突变体的冷驯化表型相比可以得出结论, 在冷驯化后的植物抗冻性中, 相较于CBF1及CBF3, CBF2发挥更重要的作用(Zhao et al., 2016). ... ... 还在茎中表达(Novillo et al., 2007).其次, 基因表达分析显示, CBF1及CBF3表达水平在低温诱导1个小时左右即达到峰值, 而CBF2则需要2小时才会达到峰值.低温条件下, CBF2还可以负反馈调节CBF1和CBF3的表达(Novillo et al., 2004), 如启动子区域插入T-DNA的cbf2突变体表现出抗冻的表型, 这可能是由于突变体中CBF1及CBF3基因过量表达造成的(Novillo et al., 2004, 2007).然而, Zhao等(2016)利用CRISPR/Cas9产生的cbf2突变体表现出冻敏感表型.目前, 猜测cbf突变体的以上表型差异可能是由于突变形式不同或植株生长状态不同等原因所致.由于CBF基因的启动子上没有CRT/DRE作用元件, 因此CBF2对CBF1及CBF3的转录调控可能不是直接的, 这其中的分子机制有待进一步研究.CBF1及CBF3的RNAi植株以及CBF1、CBF3的antisense植株中, CBF2的表达量并没有变化(Novillo et al., 2007).最近, Jia等(2016)研究表明, 利用CRISPR/Cas9产生的cbf1/cbf3双突变体在冷驯化后也具有敏感表型.这些结果暗示, CBF1和CBF3并不能调控CBF2基因的表达.有趣的是, 朱健康实验室利用CRISPR/Cas9技术获得的cbf1/cbf3双突变体中, CBF2的表达有2倍左右的上调, 并且在冷驯化后具有显著的抗冻表型(Zhao et al., 2016).因此, CBF1-CBF3相互的调控关系仍有待进一步研究.虽然以上2项研究中, cbf单突变体和双突变体的抗冻表型及基因表达水平有所不同, 但是cbf1/cbf2/cbf3三突变体的表型非常一致, 均是在冷驯化后产生极度冻敏感的表型(Jia et al., 2016; Zhao et al., 2016).与cbf1/cbf3双突变体的冷驯化表型相比可以得出结论, 在冷驯化后的植物抗冻性中, 相较于CBF1及CBF3, CBF2发挥更重要的作用(Zhao et al., 2016). ... ... , 2007).然而, Zhao等(2016)利用CRISPR/Cas9产生的cbf2突变体表现出冻敏感表型.目前, 猜测cbf突变体的以上表型差异可能是由于突变形式不同或植株生长状态不同等原因所致.由于CBF基因的启动子上没有CRT/DRE作用元件, 因此CBF2对CBF1及CBF3的转录调控可能不是直接的, 这其中的分子机制有待进一步研究.CBF1及CBF3的RNAi植株以及CBF1、CBF3的antisense植株中, CBF2的表达量并没有变化(Novillo et al., 2007).最近, Jia等(2016)研究表明, 利用CRISPR/Cas9产生的cbf1/cbf3双突变体在冷驯化后也具有敏感表型.这些结果暗示, CBF1和CBF3并不能调控CBF2基因的表达.有趣的是, 朱健康实验室利用CRISPR/Cas9技术获得的cbf1/cbf3双突变体中, CBF2的表达有2倍左右的上调, 并且在冷驯化后具有显著的抗冻表型(Zhao et al., 2016).因此, CBF1-CBF3相互的调控关系仍有待进一步研究.虽然以上2项研究中, cbf单突变体和双突变体的抗冻表型及基因表达水平有所不同, 但是cbf1/cbf2/cbf3三突变体的表型非常一致, 均是在冷驯化后产生极度冻敏感的表型(Jia et al., 2016; Zhao et al., 2016).与cbf1/cbf3双突变体的冷驯化表型相比可以得出结论, 在冷驯化后的植物抗冻性中, 相较于CBF1及CBF3, CBF2发挥更重要的作用(Zhao et al., 2016). ... ... 的表达量并没有变化(Novillo et al., 2007).最近, Jia等(2016)研究表明, 利用CRISPR/Cas9产生的cbf1/cbf3双突变体在冷驯化后也具有敏感表型.这些结果暗示, CBF1和CBF3并不能调控CBF2基因的表达.有趣的是, 朱健康实验室利用CRISPR/Cas9技术获得的cbf1/cbf3双突变体中, CBF2的表达有2倍左右的上调, 并且在冷驯化后具有显著的抗冻表型(Zhao et al., 2016).因此, CBF1-CBF3相互的调控关系仍有待进一步研究.虽然以上2项研究中, cbf单突变体和双突变体的抗冻表型及基因表达水平有所不同, 但是cbf1/cbf2/cbf3三突变体的表型非常一致, 均是在冷驯化后产生极度冻敏感的表型(Jia et al., 2016; Zhao et al., 2016).与cbf1/cbf3双突变体的冷驯化表型相比可以得出结论, 在冷驯化后的植物抗冻性中, 相较于CBF1及CBF3, CBF2发挥更重要的作用(Zhao et al., 2016). ...
1 1995
... CBF属于AP2/ERF (APETALA 2/ethylene-res- ponsive)转录因子家族成员的一个亚家族.该家族在拟南芥中有145个成员, 均含有1个或多个保守的AP2/ ERF结构域(Ohme-Takagi and Shinshi, 1995).研究表明该结构域是转录因子中的DNA结合区域(Okam- uro et al., 1997; Riechmann and Meyerowitz, 1998).不同于AP2家族的其它亚家族, CBF家族成员只有1个AP2结构域, 并且在AP2的上下游各有一段保守的氨基酸序列PKKP/PKKPAGR (RAGRxxKFx ETRHP)和DSAWR (Jaglo et al., 2001; Canella et al., 2010).将PKKPAGR突变可以抑制CBF1与其下游基因COR- 15a启动子CRT/DRE的结合能力, 从而削弱CBF1对COR15a基因的冷诱导水平调控, 说明该基序对CBF行使其转录因子功能是必需的(Canella et al., 2010). ...
1 1997
... CBF属于AP2/ERF (APETALA 2/ethylene-res- ponsive)转录因子家族成员的一个亚家族.该家族在拟南芥中有145个成员, 均含有1个或多个保守的AP2/ ERF结构域(Ohme-Takagi and Shinshi, 1995).研究表明该结构域是转录因子中的DNA结合区域(Okam- uro et al., 1997; Riechmann and Meyerowitz, 1998).不同于AP2家族的其它亚家族, CBF家族成员只有1个AP2结构域, 并且在AP2的上下游各有一段保守的氨基酸序列PKKP/PKKPAGR (RAGRxxKFx ETRHP)和DSAWR (Jaglo et al., 2001; Canella et al., 2010).将PKKPAGR突变可以抑制CBF1与其下游基因COR- 15a启动子CRT/DRE的结合能力, 从而削弱CBF1对COR15a基因的冷诱导水平调控, 说明该基序对CBF行使其转录因子功能是必需的(Canella et al., 2010). ...
5 2015
... 遗传分析表明CBF在低温信号途径中起关键作用.例如, 过表达CBF1-3均使拟南芥植株的抗冻性明显增强.进一步检测植物体内的下游冷响应基因, 发现约100个COR基因被组成型诱导, 从而使未经冷驯化的植株也能获得抗冻性(Gilmour et al., 1998; Jaglo- Ottosen et al., 1998; Liu et al., 1998; Kasuga et al., 1999; Gilmour et al., 2004).与野生型相比, CBF1及CBF3敲减拟南芥植株的抗冻性降低约60% (Novillo et al., 2007).在拟南芥中过表达CBF2的DNA结合域形成的dominant negative转基因植株中, CBF2可以结合在CRT/DRE作用位点却不能激活下游基因, 从而使植株呈现冻敏感表型(Park et al., 2015).为了进一步探究CBF1-CBF3的功能, 本实验室和上海植物逆境中心朱健康实验室分别利用CRISPR/Cas9技术获得了cbf1/cbf2/cbf3三突变体(Jia et al., 2016; Zhao et al., 2016).与野生型相比, 三突变体在非冷驯化时没有或具有轻微冻敏感表型, 而在冷驯化后表现出强烈的冻敏感表型.对突变体进行RNA-seq分析, 显示CBF突变影响了全转录组10%-20%的COR基因表达(Jia et al., 2016; Zhao et al., 2016).这些结果表明, CBF1- CBF3在低温信号途径中发挥重要的调控作用. ... ... 截至目前, 在油菜(Brassica campestris)、小麦(Triticum aestivum)、黑麦(Secale cereale)、番茄(Lycopersicon esculentum)、水稻(Oryza sativa)及玉米(Zea mays)等植物中均鉴定到了CBF转录因子(Jaglo et al., 2001; Kasuga et al., 2004; Qin et al., 2004), 并且都具有冷诱导特性; 同时, 在其它物种中过表达拟南芥CBF也可以增强植物的抗冻性(Jaglo et al., 2001; Kasuga et al., 2004).在拟南芥中过表达玉米DREB1A也会产生类似的抗冻效果(Qin et al., 2004), 说明植物中CBF在低温信号途径中的作用十分保守.虽然一些研究结果暗示, CBF1-CBF3在调节冷响应基因的功能上具有冗余性(Park et al., 2015), 但它们之间实则存在差异.首先, 三者的表达模式有所差异: CBF1及CBF3主要在根、下胚轴及子叶中表达; 而CBF2则在下胚轴、子叶及第1、2对真叶中表达, 并不在根中表达(Novillo et al., 2007).当植株遭受低温胁迫时, CBF1及CBF3基因在叶片、萼片及角果中表达, 而CBF2还在茎中表达(Novillo et al., 2007).其次, 基因表达分析显示, CBF1及CBF3表达水平在低温诱导1个小时左右即达到峰值, 而CBF2则需要2小时才会达到峰值.低温条件下, CBF2还可以负反馈调节CBF1和CBF3的表达(Novillo et al., 2004), 如启动子区域插入T-DNA的cbf2突变体表现出抗冻的表型, 这可能是由于突变体中CBF1及CBF3基因过量表达造成的(Novillo et al., 2004, 2007).然而, Zhao等(2016)利用CRISPR/Cas9产生的cbf2突变体表现出冻敏感表型.目前, 猜测cbf突变体的以上表型差异可能是由于突变形式不同或植株生长状态不同等原因所致.由于CBF基因的启动子上没有CRT/DRE作用元件, 因此CBF2对CBF1及CBF3的转录调控可能不是直接的, 这其中的分子机制有待进一步研究.CBF1及CBF3的RNAi植株以及CBF1、CBF3的antisense植株中, CBF2的表达量并没有变化(Novillo et al., 2007).最近, Jia等(2016)研究表明, 利用CRISPR/Cas9产生的cbf1/cbf3双突变体在冷驯化后也具有敏感表型.这些结果暗示, CBF1和CBF3并不能调控CBF2基因的表达.有趣的是, 朱健康实验室利用CRISPR/Cas9技术获得的cbf1/cbf3双突变体中, CBF2的表达有2倍左右的上调, 并且在冷驯化后具有显著的抗冻表型(Zhao et al., 2016).因此, CBF1-CBF3相互的调控关系仍有待进一步研究.虽然以上2项研究中, cbf单突变体和双突变体的抗冻表型及基因表达水平有所不同, 但是cbf1/cbf2/cbf3三突变体的表型非常一致, 均是在冷驯化后产生极度冻敏感的表型(Jia et al., 2016; Zhao et al., 2016).与cbf1/cbf3双突变体的冷驯化表型相比可以得出结论, 在冷驯化后的植物抗冻性中, 相较于CBF1及CBF3, CBF2发挥更重要的作用(Zhao et al., 2016). ... ... 尽管CBF在冷诱导基因调控中发挥重要作用, 但植物中还存在其它转录因子调控COR基因.Thom- show实验室通过对CBF过表达株系的RNA-seq数据分析, 发现CBF2与转录因子HSFC1、ZAT12、ZF、ZAT10及CZF1共同调控下游COR基因(当然也有像GOL3这样完全依赖CBF的冷响应基因) (Park et al., 2015), 同时多项研究表明植物中也存在不依赖于CBF的冷响应基因(Achard et al., 2008; Park et al., 2015; Jia et al., 2016; Zhao et al., 2016), 表明植物中的冷响应基因调控网络非常复杂且具有内在联系, 这其中的更多调控机制还有待进一步研究. ... ... ; Park et al., 2015; Jia et al., 2016; Zhao et al., 2016), 表明植物中的冷响应基因调控网络非常复杂且具有内在联系, 这其中的更多调控机制还有待进一步研究. ... ... 一系列研究表明CBF参与植物的生长发育过程.过表达CBF导致植株矮小, 且与野生型相比, 开花时间明显延迟(Gilmour et al., 2004; Park et al., 2015).对突变体的研究表明, cbf1/cbf2/cbf3三突变体种子萌发率与野生型相比降低一半, 根生长速率略慢于野生型, 植株的莲座叶数目减少, 形态偏小, 生物量也低于野生型(Zhao et al., 2016).这些结果说明, CBF是植物生长发育过程中的关键因素.Jia等(2016)研究表明, 低温下无论是土中还是培养皿上生长的cbf1/cbf2/cbf3三突变体植株均明显大于野生型, 说明CBF影响了低温胁迫下植物的生长发育(Jia et al., 2016).有趣的是, 外源施加影响植物细胞伸长的植物激素赤霉素(gibberellin acid, GA)可以回复CBF1过表达植株的生长发育矮小表型(Achard et al., 2008).过表达CBF1可以激活植物体内GA2ox基因的表达, 使植物体内活性形式的GA含量下降, 造成GA信号途径的负调节因子DELLA蛋白在植物体内高水平积累, 从而导致植株生长受到抑制.DELLA基因突变可以部分回复CBF1过表达植株的矮小表型, 这些结果暗示, CBF在生长发育中的作用需要GA及DELLA蛋白的参与(Achard et al., 2008).不仅CBF影响植物的生长发育, CBF的上游调控因子如ICE1、ICE2、EIN3、BZR1、PIF3/4/7和SOC1等也全部参与调控植物的生长发育, 突变体均表现出各种生长发育表型, 这暗示着植物产生对低温胁迫的抗性很可能需要以牺牲生长发育作为代价.最新研究表明, 植物面对低温胁迫时, 会自主启动细胞死亡机制, 优先杀死未成熟的小柱干细胞, 使根部静止中心维持高浓度生长素, 有利于干细胞巢(stem cell niche)抵抗低温胁迫(Hong et al., 2017).但这一机制具有特异性, CBF是否参与这一过程目前仍有待研究.植物面对低温或者其它胁迫可能要做出选择: 是继续正常生长发育从而造成对胁迫的敏感, 还是牺牲生长发育, 利用更多能量产生抵抗物质来对抗逆境? CBF可能参与低温胁迫及生长发育调控, 寻找到一种平衡植物抗冻及生长发育受损的调控机制可能是后续需要认真研究的科学问题. ...
2 2004
... 截至目前, 在油菜(Brassica campestris)、小麦(Triticum aestivum)、黑麦(Secale cereale)、番茄(Lycopersicon esculentum)、水稻(Oryza sativa)及玉米(Zea mays)等植物中均鉴定到了CBF转录因子(Jaglo et al., 2001; Kasuga et al., 2004; Qin et al., 2004), 并且都具有冷诱导特性; 同时, 在其它物种中过表达拟南芥CBF也可以增强植物的抗冻性(Jaglo et al., 2001; Kasuga et al., 2004).在拟南芥中过表达玉米DREB1A也会产生类似的抗冻效果(Qin et al., 2004), 说明植物中CBF在低温信号途径中的作用十分保守.虽然一些研究结果暗示, CBF1-CBF3在调节冷响应基因的功能上具有冗余性(Park et al., 2015), 但它们之间实则存在差异.首先, 三者的表达模式有所差异: CBF1及CBF3主要在根、下胚轴及子叶中表达; 而CBF2则在下胚轴、子叶及第1、2对真叶中表达, 并不在根中表达(Novillo et al., 2007).当植株遭受低温胁迫时, CBF1及CBF3基因在叶片、萼片及角果中表达, 而CBF2还在茎中表达(Novillo et al., 2007).其次, 基因表达分析显示, CBF1及CBF3表达水平在低温诱导1个小时左右即达到峰值, 而CBF2则需要2小时才会达到峰值.低温条件下, CBF2还可以负反馈调节CBF1和CBF3的表达(Novillo et al., 2004), 如启动子区域插入T-DNA的cbf2突变体表现出抗冻的表型, 这可能是由于突变体中CBF1及CBF3基因过量表达造成的(Novillo et al., 2004, 2007).然而, Zhao等(2016)利用CRISPR/Cas9产生的cbf2突变体表现出冻敏感表型.目前, 猜测cbf突变体的以上表型差异可能是由于突变形式不同或植株生长状态不同等原因所致.由于CBF基因的启动子上没有CRT/DRE作用元件, 因此CBF2对CBF1及CBF3的转录调控可能不是直接的, 这其中的分子机制有待进一步研究.CBF1及CBF3的RNAi植株以及CBF1、CBF3的antisense植株中, CBF2的表达量并没有变化(Novillo et al., 2007).最近, Jia等(2016)研究表明, 利用CRISPR/Cas9产生的cbf1/cbf3双突变体在冷驯化后也具有敏感表型.这些结果暗示, CBF1和CBF3并不能调控CBF2基因的表达.有趣的是, 朱健康实验室利用CRISPR/Cas9技术获得的cbf1/cbf3双突变体中, CBF2的表达有2倍左右的上调, 并且在冷驯化后具有显著的抗冻表型(Zhao et al., 2016).因此, CBF1-CBF3相互的调控关系仍有待进一步研究.虽然以上2项研究中, cbf单突变体和双突变体的抗冻表型及基因表达水平有所不同, 但是cbf1/cbf2/cbf3三突变体的表型非常一致, 均是在冷驯化后产生极度冻敏感的表型(Jia et al., 2016; Zhao et al., 2016).与cbf1/cbf3双突变体的冷驯化表型相比可以得出结论, 在冷驯化后的植物抗冻性中, 相较于CBF1及CBF3, CBF2发挥更重要的作用(Zhao et al., 2016). ... ... 也会产生类似的抗冻效果(Qin et al., 2004), 说明植物中CBF在低温信号途径中的作用十分保守.虽然一些研究结果暗示, CBF1-CBF3在调节冷响应基因的功能上具有冗余性(Park et al., 2015), 但它们之间实则存在差异.首先, 三者的表达模式有所差异: CBF1及CBF3主要在根、下胚轴及子叶中表达; 而CBF2则在下胚轴、子叶及第1、2对真叶中表达, 并不在根中表达(Novillo et al., 2007).当植株遭受低温胁迫时, CBF1及CBF3基因在叶片、萼片及角果中表达, 而CBF2还在茎中表达(Novillo et al., 2007).其次, 基因表达分析显示, CBF1及CBF3表达水平在低温诱导1个小时左右即达到峰值, 而CBF2则需要2小时才会达到峰值.低温条件下, CBF2还可以负反馈调节CBF1和CBF3的表达(Novillo et al., 2004), 如启动子区域插入T-DNA的cbf2突变体表现出抗冻的表型, 这可能是由于突变体中CBF1及CBF3基因过量表达造成的(Novillo et al., 2004, 2007).然而, Zhao等(2016)利用CRISPR/Cas9产生的cbf2突变体表现出冻敏感表型.目前, 猜测cbf突变体的以上表型差异可能是由于突变形式不同或植株生长状态不同等原因所致.由于CBF基因的启动子上没有CRT/DRE作用元件, 因此CBF2对CBF1及CBF3的转录调控可能不是直接的, 这其中的分子机制有待进一步研究.CBF1及CBF3的RNAi植株以及CBF1、CBF3的antisense植株中, CBF2的表达量并没有变化(Novillo et al., 2007).最近, Jia等(2016)研究表明, 利用CRISPR/Cas9产生的cbf1/cbf3双突变体在冷驯化后也具有敏感表型.这些结果暗示, CBF1和CBF3并不能调控CBF2基因的表达.有趣的是, 朱健康实验室利用CRISPR/Cas9技术获得的cbf1/cbf3双突变体中, CBF2的表达有2倍左右的上调, 并且在冷驯化后具有显著的抗冻表型(Zhao et al., 2016).因此, CBF1-CBF3相互的调控关系仍有待进一步研究.虽然以上2项研究中, cbf单突变体和双突变体的抗冻表型及基因表达水平有所不同, 但是cbf1/cbf2/cbf3三突变体的表型非常一致, 均是在冷驯化后产生极度冻敏感的表型(Jia et al., 2016; Zhao et al., 2016).与cbf1/cbf3双突变体的冷驯化表型相比可以得出结论, 在冷驯化后的植物抗冻性中, 相较于CBF1及CBF3, CBF2发挥更重要的作用(Zhao et al., 2016). ...
1 1998
... CBF属于AP2/ERF (APETALA 2/ethylene-res- ponsive)转录因子家族成员的一个亚家族.该家族在拟南芥中有145个成员, 均含有1个或多个保守的AP2/ ERF结构域(Ohme-Takagi and Shinshi, 1995).研究表明该结构域是转录因子中的DNA结合区域(Okam- uro et al., 1997; Riechmann and Meyerowitz, 1998).不同于AP2家族的其它亚家族, CBF家族成员只有1个AP2结构域, 并且在AP2的上下游各有一段保守的氨基酸序列PKKP/PKKPAGR (RAGRxxKFx ETRHP)和DSAWR (Jaglo et al., 2001; Canella et al., 2010).将PKKPAGR突变可以抑制CBF1与其下游基因COR- 15a启动子CRT/DRE的结合能力, 从而削弱CBF1对COR15a基因的冷诱导水平调控, 说明该基序对CBF行使其转录因子功能是必需的(Canella et al., 2010). ...
2 2009
... 植物的开花过程也受到低温调控, 低温可抑制开花而高温则促进开花(Blázquez et al., 2003).开花途径重要的调节因子SOC1 (suppressor of overexpression of constans 1)编码1个MADS类转录因子, 研究表明SOC1可以直接结合CBF启动子的CArG元件, 负调节CBF基因的表达(Seo et al., 2009).与此对应, soc1突变体也表现出明显的抗冻性, 说明SOC1是开花途径与低温信号途径相互作用的节点(Seo et al., 2009).自2000年以来, 不断有研究表明, CBF及其下游冷响应基因的表达存在节律现象(Har- mer et al., 2000; Bieniawska et al., 2008; Espinoza et al., 2008; Mikkelsen and Thomashow, 2009), 其基因表达在黎明后8小时达到峰值, 并在黎明后20小时达到低谷.多项研究表明, 节律可以同时正向及负向调控CBF基因的转录水平.节律中心调控因子包括MYB类转录因子CCA1 (circadian clock associated 1)与LHY (late elongated hypocotyl)以及PRR (pseudoresponse regulator)蛋白TOC1, 它们相互调控彼此的基因表达, 从而形成反馈环机制.三突变体prr5/prr7/prr9中CBF基因组成型高水平表达, 并表现出明显的抗冻表型, 暗示PRRs参与抑制CBF基因表达(Nakamichi et al., 2009, 2012).2011年, Thom- ashow实验室发现拟南芥中央振荡器因子CCA1及LHY可以正调控CBF的表达.CCA1及LHY均编码MYB类转录因子, 它们通过结合CBF1-CBF3基因启动子上的EE及CBS结合位点, 直接调控CBF基因表达.cca1/lhy双突变体中CBF基因表达水平大幅下调, 并且CBF基因表达的节律性也有所减弱(Dong et al., 2011).CBF下游调控基因COR15A、COR47及COR78表达水平也显著下调.双突变体在冷驯化前后均表现出敏感表型, 说明节律调控因子CCA1及LHY通过直接调控CBF的表达, 参与低温信号途径(Dong et al., 2011).进一步研究发现, CCA1的2个转录本CCA1α及CCA1β均参与低温信号途径.低温抑制CCA1β的表达, 而CCA1β通过与CCA1α相互作用, 抑制CCA1α的表达(Seo et al., 2012). ... ... 突变体也表现出明显的抗冻性, 说明SOC1是开花途径与低温信号途径相互作用的节点(Seo et al., 2009).自2000年以来, 不断有研究表明, CBF及其下游冷响应基因的表达存在节律现象(Har- mer et al., 2000; Bieniawska et al., 2008; Espinoza et al., 2008; Mikkelsen and Thomashow, 2009), 其基因表达在黎明后8小时达到峰值, 并在黎明后20小时达到低谷.多项研究表明, 节律可以同时正向及负向调控CBF基因的转录水平.节律中心调控因子包括MYB类转录因子CCA1 (circadian clock associated 1)与LHY (late elongated hypocotyl)以及PRR (pseudoresponse regulator)蛋白TOC1, 它们相互调控彼此的基因表达, 从而形成反馈环机制.三突变体prr5/prr7/prr9中CBF基因组成型高水平表达, 并表现出明显的抗冻表型, 暗示PRRs参与抑制CBF基因表达(Nakamichi et al., 2009, 2012).2011年, Thom- ashow实验室发现拟南芥中央振荡器因子CCA1及LHY可以正调控CBF的表达.CCA1及LHY均编码MYB类转录因子, 它们通过结合CBF1-CBF3基因启动子上的EE及CBS结合位点, 直接调控CBF基因表达.cca1/lhy双突变体中CBF基因表达水平大幅下调, 并且CBF基因表达的节律性也有所减弱(Dong et al., 2011).CBF下游调控基因COR15A、COR47及COR78表达水平也显著下调.双突变体在冷驯化前后均表现出敏感表型, 说明节律调控因子CCA1及LHY通过直接调控CBF的表达, 参与低温信号途径(Dong et al., 2011).进一步研究发现, CCA1的2个转录本CCA1α及CCA1β均参与低温信号途径.低温抑制CCA1β的表达, 而CCA1β通过与CCA1α相互作用, 抑制CCA1α的表达(Seo et al., 2012). ...
1 2012
... 植物的开花过程也受到低温调控, 低温可抑制开花而高温则促进开花(Blázquez et al., 2003).开花途径重要的调节因子SOC1 (suppressor of overexpression of constans 1)编码1个MADS类转录因子, 研究表明SOC1可以直接结合CBF启动子的CArG元件, 负调节CBF基因的表达(Seo et al., 2009).与此对应, soc1突变体也表现出明显的抗冻性, 说明SOC1是开花途径与低温信号途径相互作用的节点(Seo et al., 2009).自2000年以来, 不断有研究表明, CBF及其下游冷响应基因的表达存在节律现象(Har- mer et al., 2000; Bieniawska et al., 2008; Espinoza et al., 2008; Mikkelsen and Thomashow, 2009), 其基因表达在黎明后8小时达到峰值, 并在黎明后20小时达到低谷.多项研究表明, 节律可以同时正向及负向调控CBF基因的转录水平.节律中心调控因子包括MYB类转录因子CCA1 (circadian clock associated 1)与LHY (late elongated hypocotyl)以及PRR (pseudoresponse regulator)蛋白TOC1, 它们相互调控彼此的基因表达, 从而形成反馈环机制.三突变体prr5/prr7/prr9中CBF基因组成型高水平表达, 并表现出明显的抗冻表型, 暗示PRRs参与抑制CBF基因表达(Nakamichi et al., 2009, 2012).2011年, Thom- ashow实验室发现拟南芥中央振荡器因子CCA1及LHY可以正调控CBF的表达.CCA1及LHY均编码MYB类转录因子, 它们通过结合CBF1-CBF3基因启动子上的EE及CBS结合位点, 直接调控CBF基因表达.cca1/lhy双突变体中CBF基因表达水平大幅下调, 并且CBF基因表达的节律性也有所减弱(Dong et al., 2011).CBF下游调控基因COR15A、COR47及COR78表达水平也显著下调.双突变体在冷驯化前后均表现出敏感表型, 说明节律调控因子CCA1及LHY通过直接调控CBF的表达, 参与低温信号途径(Dong et al., 2011).进一步研究发现, CCA1的2个转录本CCA1α及CCA1β均参与低温信号途径.低温抑制CCA1β的表达, 而CCA1β通过与CCA1α相互作用, 抑制CCA1α的表达(Seo et al., 2012). ...
3 2012
... 另一个比较重要的CBF负调节因子是乙烯信号途径的重要组分EIN3.EIN3/EIL1作为功能冗余的中心转录因子, 在乙烯信号通路中起正调控作用.EIN3可以直接结合到CBF启动子区的EBS作用元件, 负向调控CBF基因表达.缺失突变体ein3表现出强烈的抗冻表型, 说明EIN3作为乙烯与低温信号途径的交叉节点, 参与激素与低温的交叉调控(Shi et al., 2012).同时EIN3还可以结合在A型ARR基因的启动子区, 负调控ARR5、ARR7和ARR15基因的表达水平, 参与植物抗冻性的调控(Shi et al., 2012). ... ... 基因的表达水平, 参与植物抗冻性的调控(Shi et al., 2012). ... ... 除了节律可调控植物对低温的响应, 光信号与光周期也被发现参与植物的抗冻性调节(Franklin and Whitelam, 2007; Lee and Thomashow, 2012).当植物生长在较低温度(16°C)且红光与远红光比(R/FR)降低时, 植物体内的CBF基因节律性表达增强, COR基因表达上调, 使植株产生更强的抗冻性, 这与红光及远红光受体光敏色素有关, 暗示环境温度可通过光敏色素调控CBF基因的节律性及其下游基因的表达(Franklin and Whitelam, 2007).与长日照相比, 生长在短日照下的野生型植株表现出更强的抗冻性, 这可能与短日照下植株中的CBF表达倍数更高有关.进一步研究发现, 长日照下, 2个光受体结合蛋白PIF4和PIF7蛋白水平增加, 它们通过直接结合在CBF3的G-box及E-box区, 负调控CBF的表达.CBF下游靶基因COR15a和Gols3的表达水平同样受到抑制, 因此造成植物抗冻性减弱(Lee and Thomashow, 2012).PIF3蛋白在黑暗时活性增强, 抑制植物的光形态建成(Ni et al., 1998; Leivar et al., 2008; Leivar and Monte, 2014).光照射下, 光敏色素与PIF蛋白相互作用, 促进PIF蛋白降解(Ni et al., 2014).PIF3可以被PRRK蛋白磷酸化并通过LRB Cullin 3 E3泛素连接酶降解(Ni et al., 2014, 2017).本实验室的最新研究表明, 乙烯信号途径的E3泛素连接酶EBF1和EBF2可以通过与PIF3相互作用, 使其经由26S蛋白酶体途径降解(Jiang et al., 2017).PIF3直接结合在CBF基因的启动子区, 负调控其表达, 是植物抗冻性的负调控因子.低温及黑暗条件下, EBF蛋白降解(Shi et al., 2012), 导致PIF3蛋白积累, 从而调控CBF基因的表达(Jiang et al., 2017).以上研究结果暗示, 光和温度对植物冷驯化过程的影响密不可分, PIF作为CBF重要的负调控因子, 平衡植物的抗冻性和生长发育过程. ...
1 2012
... 另一个非常值得关注的问题是作用于CBF最上游的植物低温感受器究竟是什么? 2015年, 种康课题组通过QTL发现水稻中的COLD1基因介导粳稻耐冷性(Ma et al., 2015).COLD1定位在细胞质膜和内质网膜上, 与拟南芥中G蛋白α亚基互作蛋白GTG1/2高度同源, 被认为是一个低温感受器.它通过与G蛋白α亚基互作, 影响G蛋白活性, 调控低温激活的Ca2+内流, 从而影响籼稻的耐冷性.基因表达分析显示COLD1的互补株系中CBF基因表达上调, 说明COLD1可能参与CBF的调控.该基因上的1个SNP是影响水稻耐冷的关键位点, 暗示COLD1基因在自然选择过程中的重要性(Ma et al., 2015).那么除此之外是否还有其它的低温感受器存在? 蓝藻中的温度感受器Hik33是一类组蛋白激酶(Zabulon et al., 2007; Shimura et al., 2012).植物中的组蛋白激酶作为激素受体发挥重要作用, 它们是否也是低温的感受器? 还有研究表明光受体phyB作为温度感受器调控植物对室温环境温度的感受(Jung et al., 2016; Legris et al., 2016), 但其是否参与低温的感受仍不清楚, 这些问题都有待进一步验证. ...
1 1997
... 在拟南芥(Arabidopsis thaliana)基因组中存在3个CBF基因, 属于一类转录因子家族CBF/DREB1 (de- hydration-responsive element-binding factors 1)基因.CBF家族成员串联排列在拟南芥第4条染色体上, 分别命名为CBF1 (DREB1B)、CBF2 (DREB1C)和CBF3 (DREB1A) (Gilmour et al., 1998; Liu et al., 1998).1997-1998年, Thomashow等利用酵母单杂交等技术相继鉴定到了CBF1-CBF3 (Stockinger et al., 1997; Gilmour et al., 1998; Liu et al., 1998), 它们可以与一段保守的CRT/DRE (C-repeat/dehydration response element)调控元件CCGAC结合(Baker et al., 1994), 该元件多出现在冷诱导COR (Cold- regulated)基因的启动子区域(Medina et al., 2011).氨基酸序列比对结果显示, CBF1-CBF3三者之间具有很高的相似性(>85%), 暗示它们可能起源于同一个基因(Gilmour et al., 1998; Medina et al., 1999).过量表达CBF1、CBF2及CBF3均能大幅提高植株的抗冻性, 并显著诱导植株体内COR基因的表达(Liu et al., 1998). ...
1 2005
... 一系列激素信号途径中的调节组分被证明也会直接或间接参与CBF的转录调控.本实验室最新研究表明, BR信号途径的关键调节因子BZR1 (brassinazole-resistant 1)及其同源蛋白BES1 (BRI1-EMS- suppressor 1)通过结合CBF1与CBF2启动子上的E-box及BRRE结合位点, 正调控二者的表达(Li et al., 2017b).BZR1和BES1都是bHLH类转录因子, 在BR信号途径中起正调控作用(He et al., 2005; Yin et al., 2005), 它们的功能获得型突变体表现出强烈的抗冻表型(Li et al., 2017b).另一个BR信号途径的转录因子CESTA直接结合所有CBF启动子, 并组成性激活CBF及下游COR基因表达, 正调控植物的抗冻性(Eremina et al., 2016).进一步研究发现, 低温可以诱导非磷酸化形式的BZR1蛋白积累, 进而调控其磷酸化的蛋白激酶BIN2 (brassinosteroid insensitive 2)也作为负调节子参与植物的抗冻性调控.转录组分析数据表明, BZR1除了直接调节CBF基因表达, 还参与正向及负向调控一系列不依赖CBF的冷诱导基因的表达, 说明BZR1作为重要的调节因子, 在低温信号途径的精细调控中可能起到不同的关键作用, 而这其中的分子机制还有待进一步研究(Li et al., 2017b). ...
1 2007
... 另一个非常值得关注的问题是作用于CBF最上游的植物低温感受器究竟是什么? 2015年, 种康课题组通过QTL发现水稻中的COLD1基因介导粳稻耐冷性(Ma et al., 2015).COLD1定位在细胞质膜和内质网膜上, 与拟南芥中G蛋白α亚基互作蛋白GTG1/2高度同源, 被认为是一个低温感受器.它通过与G蛋白α亚基互作, 影响G蛋白活性, 调控低温激活的Ca2+内流, 从而影响籼稻的耐冷性.基因表达分析显示COLD1的互补株系中CBF基因表达上调, 说明COLD1可能参与CBF的调控.该基因上的1个SNP是影响水稻耐冷的关键位点, 暗示COLD1基因在自然选择过程中的重要性(Ma et al., 2015).那么除此之外是否还有其它的低温感受器存在? 蓝藻中的温度感受器Hik33是一类组蛋白激酶(Zabulon et al., 2007; Shimura et al., 2012).植物中的组蛋白激酶作为激素受体发挥重要作用, 它们是否也是低温的感受器? 还有研究表明光受体phyB作为温度感受器调控植物对室温环境温度的感受(Jung et al., 2016; Legris et al., 2016), 但其是否参与低温的感受仍不清楚, 这些问题都有待进一步验证. ...
1 2017
... ICE1作为重要的CBF调节因子, 自身也被很多组分精细调控.目前已知的对ICE1的翻译后修饰包括HOS1 (high osmotic expression 1)介导的泛素化、SIZ1 (SAP and Miz 1)介导的SUMO化以及OST1 (open stomata 1)介导的磷酸化等, 这些修饰通过调节ICE1的蛋白水平或转录水平参与调控冷信号途径.同时一些转录抑制子(MYB15和JAZ)还可以与ICE1相互作用, 从而调节它的转录活性.HOS1与ICE1相互作用, 泛素化ICE1蛋白, 使其通过26S蛋白酶体途径进行降解(Dong et al., 2006).HOS1过表达植株中CBF3基因表达水平下调, 植株表现出冻敏感表型(Dong et al., 2006).ICE1还受到另一种E3蛋白SIZ1的SUMO化调控(Miura et al., 2007).SIZ1使ICE1蛋白SUMO化, 并减弱ICE1的泛素化, 从而维持ICE1蛋白的稳定性.siz1突变体中CBF3基因表达水平下调, 植株呈冻敏感表型(Miura et al., 2007).JA信号途径的负调节因子JAZ1 (jasmonate ZIM-domain)与JAZ4通过与ICE1蛋白具有bHLH结构域的C端相互作用, 抑制ICE1的转录活性, 从而参与对低温信号途径的调控(Hu et al., 2013).与之相对应, 过表达JAZ1及JAZ4的转基因植株, 以及JA合成途径及信号途径中一些组分的突变体均表现出低温敏感的表型(Hu et al., 2013).本实验室研究表明, 低温可以激活ABA信号途径中的重要激酶OST1, 使其磷酸化ICE1第278位Ser, 正调控ICE1蛋白的稳定性及转录活性, 从而促进下游CBF基因的表达(Ding et al., 2015).OST1对ICE1的磷酸化作用还可以抑制其与HOS1的互作, 从而抑制HOS1对ICE1的降解.以上结果说明OST1作为蛋白激酶, 在低温信号途径中起关键正调控作用(Ding et al., 2015).除此之外, 本实验室及朱健康研究组同时发现, 低温可以激活丝裂原活化蛋白激酶MPK3及MPK6, 它们通过磷酸化ICE1 (磷酸化位点与OST1对ICE1的磷酸化位点不同), 抑制ICE1蛋白的稳定性和转录活性, 从而负调控CBF基因表达及植物的抗冻性(Li et al., 2017a; Zhao et al., 2017).这些结果说明, ICE1作为重要的低温信号途径的转录因子, 被多种调节子不同程度地调控, 从而使植物更好地应对低温胁迫, 做出精细的应答反应. ...
7 2016
... 遗传分析表明CBF在低温信号途径中起关键作用.例如, 过表达CBF1-3均使拟南芥植株的抗冻性明显增强.进一步检测植物体内的下游冷响应基因, 发现约100个COR基因被组成型诱导, 从而使未经冷驯化的植株也能获得抗冻性(Gilmour et al., 1998; Jaglo- Ottosen et al., 1998; Liu et al., 1998; Kasuga et al., 1999; Gilmour et al., 2004).与野生型相比, CBF1及CBF3敲减拟南芥植株的抗冻性降低约60% (Novillo et al., 2007).在拟南芥中过表达CBF2的DNA结合域形成的dominant negative转基因植株中, CBF2可以结合在CRT/DRE作用位点却不能激活下游基因, 从而使植株呈现冻敏感表型(Park et al., 2015).为了进一步探究CBF1-CBF3的功能, 本实验室和上海植物逆境中心朱健康实验室分别利用CRISPR/Cas9技术获得了cbf1/cbf2/cbf3三突变体(Jia et al., 2016; Zhao et al., 2016).与野生型相比, 三突变体在非冷驯化时没有或具有轻微冻敏感表型, 而在冷驯化后表现出强烈的冻敏感表型.对突变体进行RNA-seq分析, 显示CBF突变影响了全转录组10%-20%的COR基因表达(Jia et al., 2016; Zhao et al., 2016).这些结果表明, CBF1- CBF3在低温信号途径中发挥重要的调控作用. ... ... ; Zhao et al., 2016).这些结果表明, CBF1- CBF3在低温信号途径中发挥重要的调控作用. ... ... 截至目前, 在油菜(Brassica campestris)、小麦(Triticum aestivum)、黑麦(Secale cereale)、番茄(Lycopersicon esculentum)、水稻(Oryza sativa)及玉米(Zea mays)等植物中均鉴定到了CBF转录因子(Jaglo et al., 2001; Kasuga et al., 2004; Qin et al., 2004), 并且都具有冷诱导特性; 同时, 在其它物种中过表达拟南芥CBF也可以增强植物的抗冻性(Jaglo et al., 2001; Kasuga et al., 2004).在拟南芥中过表达玉米DREB1A也会产生类似的抗冻效果(Qin et al., 2004), 说明植物中CBF在低温信号途径中的作用十分保守.虽然一些研究结果暗示, CBF1-CBF3在调节冷响应基因的功能上具有冗余性(Park et al., 2015), 但它们之间实则存在差异.首先, 三者的表达模式有所差异: CBF1及CBF3主要在根、下胚轴及子叶中表达; 而CBF2则在下胚轴、子叶及第1、2对真叶中表达, 并不在根中表达(Novillo et al., 2007).当植株遭受低温胁迫时, CBF1及CBF3基因在叶片、萼片及角果中表达, 而CBF2还在茎中表达(Novillo et al., 2007).其次, 基因表达分析显示, CBF1及CBF3表达水平在低温诱导1个小时左右即达到峰值, 而CBF2则需要2小时才会达到峰值.低温条件下, CBF2还可以负反馈调节CBF1和CBF3的表达(Novillo et al., 2004), 如启动子区域插入T-DNA的cbf2突变体表现出抗冻的表型, 这可能是由于突变体中CBF1及CBF3基因过量表达造成的(Novillo et al., 2004, 2007).然而, Zhao等(2016)利用CRISPR/Cas9产生的cbf2突变体表现出冻敏感表型.目前, 猜测cbf突变体的以上表型差异可能是由于突变形式不同或植株生长状态不同等原因所致.由于CBF基因的启动子上没有CRT/DRE作用元件, 因此CBF2对CBF1及CBF3的转录调控可能不是直接的, 这其中的分子机制有待进一步研究.CBF1及CBF3的RNAi植株以及CBF1、CBF3的antisense植株中, CBF2的表达量并没有变化(Novillo et al., 2007).最近, Jia等(2016)研究表明, 利用CRISPR/Cas9产生的cbf1/cbf3双突变体在冷驯化后也具有敏感表型.这些结果暗示, CBF1和CBF3并不能调控CBF2基因的表达.有趣的是, 朱健康实验室利用CRISPR/Cas9技术获得的cbf1/cbf3双突变体中, CBF2的表达有2倍左右的上调, 并且在冷驯化后具有显著的抗冻表型(Zhao et al., 2016).因此, CBF1-CBF3相互的调控关系仍有待进一步研究.虽然以上2项研究中, cbf单突变体和双突变体的抗冻表型及基因表达水平有所不同, 但是cbf1/cbf2/cbf3三突变体的表型非常一致, 均是在冷驯化后产生极度冻敏感的表型(Jia et al., 2016; Zhao et al., 2016).与cbf1/cbf3双突变体的冷驯化表型相比可以得出结论, 在冷驯化后的植物抗冻性中, 相较于CBF1及CBF3, CBF2发挥更重要的作用(Zhao et al., 2016). ... ... ; Zhao et al., 2016).与cbf1/cbf3双突变体的冷驯化表型相比可以得出结论, 在冷驯化后的植物抗冻性中, 相较于CBF1及CBF3, CBF2发挥更重要的作用(Zhao et al., 2016). ... ... 双突变体的冷驯化表型相比可以得出结论, 在冷驯化后的植物抗冻性中, 相较于CBF1及CBF3, CBF2发挥更重要的作用(Zhao et al., 2016). ... ... 尽管CBF在冷诱导基因调控中发挥重要作用, 但植物中还存在其它转录因子调控COR基因.Thom- show实验室通过对CBF过表达株系的RNA-seq数据分析, 发现CBF2与转录因子HSFC1、ZAT12、ZF、ZAT10及CZF1共同调控下游COR基因(当然也有像GOL3这样完全依赖CBF的冷响应基因) (Park et al., 2015), 同时多项研究表明植物中也存在不依赖于CBF的冷响应基因(Achard et al., 2008; Park et al., 2015; Jia et al., 2016; Zhao et al., 2016), 表明植物中的冷响应基因调控网络非常复杂且具有内在联系, 这其中的更多调控机制还有待进一步研究. ... ... 一系列研究表明CBF参与植物的生长发育过程.过表达CBF导致植株矮小, 且与野生型相比, 开花时间明显延迟(Gilmour et al., 2004; Park et al., 2015).对突变体的研究表明, cbf1/cbf2/cbf3三突变体种子萌发率与野生型相比降低一半, 根生长速率略慢于野生型, 植株的莲座叶数目减少, 形态偏小, 生物量也低于野生型(Zhao et al., 2016).这些结果说明, CBF是植物生长发育过程中的关键因素.Jia等(2016)研究表明, 低温下无论是土中还是培养皿上生长的cbf1/cbf2/cbf3三突变体植株均明显大于野生型, 说明CBF影响了低温胁迫下植物的生长发育(Jia et al., 2016).有趣的是, 外源施加影响植物细胞伸长的植物激素赤霉素(gibberellin acid, GA)可以回复CBF1过表达植株的生长发育矮小表型(Achard et al., 2008).过表达CBF1可以激活植物体内GA2ox基因的表达, 使植物体内活性形式的GA含量下降, 造成GA信号途径的负调节因子DELLA蛋白在植物体内高水平积累, 从而导致植株生长受到抑制.DELLA基因突变可以部分回复CBF1过表达植株的矮小表型, 这些结果暗示, CBF在生长发育中的作用需要GA及DELLA蛋白的参与(Achard et al., 2008).不仅CBF影响植物的生长发育, CBF的上游调控因子如ICE1、ICE2、EIN3、BZR1、PIF3/4/7和SOC1等也全部参与调控植物的生长发育, 突变体均表现出各种生长发育表型, 这暗示着植物产生对低温胁迫的抗性很可能需要以牺牲生长发育作为代价.最新研究表明, 植物面对低温胁迫时, 会自主启动细胞死亡机制, 优先杀死未成熟的小柱干细胞, 使根部静止中心维持高浓度生长素, 有利于干细胞巢(stem cell niche)抵抗低温胁迫(Hong et al., 2017).但这一机制具有特异性, CBF是否参与这一过程目前仍有待研究.植物面对低温或者其它胁迫可能要做出选择: 是继续正常生长发育从而造成对胁迫的敏感, 还是牺牲生长发育, 利用更多能量产生抵抗物质来对抗逆境? CBF可能参与低温胁迫及生长发育调控, 寻找到一种平衡植物抗冻及生长发育受损的调控机制可能是后续需要认真研究的科学问题. ...