摘要:SCF复合体泛素连接酶E3介导的泛素化蛋白降解是翻译后水平上对生命进程进行调控的一个重要方式。它的关键组分F-box蛋白负责识别被降解的靶底物蛋白。植物F-box基因家族成员众多，极具多样性。F-box蛋白N端常含F-box基序，C端常为蛋白互作保守结构域，该结构具多样性，可识别不同底物，是F-box蛋白分类的依据。研究表明，F-box蛋白参与调控植物的许多生命进程，包括抗逆反应。本文就近年来F-box蛋白在植物抗逆反应中的作用机制进行总结。F-box蛋白大多以SCF复合体泛素连接酶E3介导的泛素化蛋白降解目标蛋白的方式调控抗逆反应，也有不依赖形成SCF复合体的方式行使功能，不少F-box蛋白参与了植物激素信号传导，通过调控转录因子活性而改变下游基因的表达，由此影响了植物的抗逆反应。基因表达谱的生物信息学预测表明，大多数F-box基因参与了植物抗逆反应，目前只有其中一小部分已报道了其抗逆调节功能。在此综述了这些F-box蛋白在植物抗逆胁迫中的研究进展。在干旱和盐碱胁迫反应中，F-box基因常通过影响植物激素脱落酸、乙烯等植物激素信号传导而调控抗逆。由于干旱和盐碱胁迫具协同性，不少F-box基因同时参与抗旱和抗盐碱胁迫，但调节方式有所不同，一些F-box基因对抗干旱和盐碱的反应具协同性，从总体上调控植物的渗透胁迫和离子毒害反应；而另一些F-box基因对干旱和盐胁迫反应的调节作用相反，它们可能在植物抗逆的精细调节中起作用。在低温胁迫反应中，F-box蛋白可调节植物抗低温的CBF信号途径。在生物胁迫反应中，F-box基因常通过影响植物激素茉莉酸和水杨酸途径来调控抗病，病原菌也以攻击植物SCF复合体使植物致病。此外，植物激素信号途径之间相互作用，共同影响抗逆反应。
关键词:F-box蛋白家族/
SCF复合体/
植物/
环境胁迫/
抗逆反应
Abstract:The UPS (ubiquitin proteasome system) mediated by SCF type E3 ubiquitin-ligase is an important mechanism to regulate biological progress at post-translation level. F-box protein, as a key component in SCF complex, could recognize its target protein for degradation. F-box gene family contains numerous members with vast diversity. In general, F-box protein contains F-box motif at N terminus and conserved domain of protein-protein interaction for recognizing target at C terminus. Due to vast diversity of conserved C terminus domains, F-box proteins could recognize wide varieties of targets. Also based on C terminal domains, F-box proteins could be divided into several subfamilies. It showed that plant F-box proteins were involved in many life processes, including response to environmental stress. Here, we reviewed current knowledge of plant F-box proteins in responding to stress. Most of the reported F-box proteins had been shown to function via SCF-dependent protein degradation, with few using SCF-independent mechanisms. Some well-understood F-box proteins were involved in phytohormone signaling pathways. Some reacted to stress through regulating the activity of transcription factors, which influenced expression of downstream genes responding to stress. Bioinformatics analyses of transcriptome showed that many predicted F-box genes were involved in stress-response reactions. Among these, only a few studies had dealt with the functions. The knowledge on the functions under environmental stress was summarized in this study. For drought, salinity and alkality stresses, F-box genes often regulated abscisic acid or ethylene signal pathways. Since drought and salt-alkaline stresses often occurred concomitantly, quite a few F-box genes had been identified to be involved in the response to both stresses in different ways. Some regulated the response to osmotic stress and ionic stress synergistically. However, some functioned inversely, suggesting that they played a role in fine regulations. For cold stress, F-box genes regulated CBF signal pathways. For biotic stress, F-box genes always regulated jasmonate and salicylic acid pathways. Meanwhile, pathogens attacked plant SCF complex for infection. Moreover, phytohormones had crosstalk to coordinate resistance in plants.
Key words:F-box protein/
SCF complex/
Plant/
Environment stress/
Response to stress
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