陈建民扬州大学生物科学与技术学院,扬州 225009

Recommendations to define generation and apply generation symbols in plant genetics

Jianmin ChenCollege of Bioscience and Biotechnology, Yangzhou University, Yangzhou 225009, China

编委: 张飞雄
收稿日期:2018-03-20修回日期:2018-04-10网络出版日期:2018-06-20

基金资助:

江苏高校生物技术品牌专业建设工程资助项目资助.PPZY2015C212

Received:2018-03-20Revised:2018-04-10Online:2018-06-20

Fund supported:

Supported by Top-notch Academic Programs Project of Jiangsu Higher Education Institutions (TAPP).PPZY2015C212

作者简介 About authors
陈建民,博士,教授,研究方向：作物遗传E-mail:jmchen@yzu.edu.cn。



摘要
遗传学是研究生物遗传与变异的科学,是探索基因的结构、功能及其变异、传递规律的生物学学科之一。植物遗传学中世代概念和划分尽管是一个简单的问题,但至今世代符号的使用仍然存在随意性,经常会出现利用不同的符号表示相同类型杂交后代的情况,如传统杂交后代以F₁或F₀表示,组织培养当代植株以R,R₀,R₁表示,从而导致遗传学基本概念的模糊。根据创建新世代的方法和遗传组成进行定义,本文提出了不同方法产生的新世代应用符号的建议,以便对植物遗传学领域的学习和研究提供借鉴和参考。
关键词： 植物遗传学;世代交替;新世代;遗传组成;世代符号

Abstract
Genetics is the science of studying the inheritance and variation of organisms. It is one of the biological disciplines that explore the rules of the structure, function, variation and transmission of genes. The concept and category of generation in plant genetics is a simple issue, but the usage of generation symbols is arbitrary so far. Different symbols are often used to express the same type of hybrid offspring, such as the traditional hybrid expressed in F₁ or F₀, and the regenerated plants in the tissue culture are expressed in R or R₀ or R₁, which leads to the fuzzy basic concepts of genetics. According to new generations generated by different methods and their genetic composition, the paper puts forward some suggestions to apply symbols to the new generation, so as to facilitate the study and research of plant genetics.
Keywords：plant genetics;metagenesis;new generation;genetic composition;generation symbol


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本文引用格式
陈建民. 植物遗传学中的世代及符号应用的建议. 遗传[J], 2018, 40(6): 508-514 doi:10.16288/j.yczz.18-071
Jianmin Chen. Recommendations to define generation and apply generation symbols in plant genetics. Hereditas(Beijing)[J], 2018, 40(6): 508-514 doi:10.16288/j.yczz.18-071


生物的世代交替(metagenesis或alternation of generations)是指在其生活史中,产生孢子的孢子体(sporophytes)世代(无性世代)与产生配子的配子体(gametophytes)世代(有性世代)有规律地交替出现的现象^[1]。世代交替在植物的生活史中表现明显,而在动物的生活史中表现不明显。有世代交替的生物从一个生殖期到下一个生殖期为一个世代(generation)。生物在世代之间的表型相似现象就是遗传(inheritance),而世代之间的表型不同现象就是变异(variation)。动物世代交替与植物世代交替因生长发育及胚胎形成不同而在新世代的表现形式上有所区别。一般而言,动物的新世代是从受精卵开始,受精卵进行分裂和分化形成胚胎,发育成新世代, 而大多数被子植物的新世代是从双受精产生的受精卵和初生胚乳核发育成种子开始。因此可以认为种下一粒种子,该种子发芽长大直至开花结果,获得新的种子,即为一个世代。种子是由不同世代来源的细胞组成,胚和胚乳是双受精的产物,是新世代的组织,而种子的种皮或果皮却来自于母体组织,非受精产物,是上个世代的组织。因此,动物和植物在世代交替的形式上有所不同,但遗传及变异规律上是相同的。

遗传学是研究生物遗传物质的结构和功能、遗传和变异规律的学科,是生物学最基本的学科之一。遗传学对世代的划分必须非常清晰。这对于遗传学的学习,以及理清遗传学研究中特定材料的来源及世代,预测各世代的遗传表现均有重要作用。虽然对于遗传学学习和研究来讲,世代概念和划分是一个简单的问题,理应认识一致,但笔者在阅读不同的遗传学和育种学教科书,尤其是植物遗传学研究论文时发现,有些作者使用世代符号的随意性比较大,利用不同的符号表示相同类型杂交后代时而可见,导致模糊概念。国内****有之,国外****也未能幸免,给读者增加了不必要的阅读障碍。笔者在多年的遗传学教学过程中深刻体会到,遗传学本身的名词概念及符号很多,正确理解和掌握概念,使用相对统一的符号,对学习和研究遗传学会起到事半功倍的效果。本文就植物遗传学中简单的世代及符号问题进行一些解读,并对世代符号的使用提出建议。

1 新世代创建途径和符号使用现状

孟德尔利用豌豆人为组配杂交组合创造新世代,对该世代的后代进行系统研究,揭示了遗传学的分离和独立分配规律,奠定了遗传学的基础,并建立了经典遗传学研究的一般方法。植物遗传学研究中通常要通过不同途径产生特定遗传基础的新世代,研究新世代繁衍后代的表型从而获得遗传和变异的特点,同时利用该世代的遗传重组所产生的新变异。在植物遗传学中,用同种内不同表型或遗传基础的个体作为亲本进行人工杂交产生的种子为新世代,称为杂种一代( the first filial generation),以符号F₁表示^[2,3,4,5],F₁种子的胚和胚乳是双亲遗传基础异质结合的产物,而种皮或果皮则来自母本。F₁自交产生F₂,F₂自交产生F₃,以此类推。该概念和世代符号已成为共识而被广泛使用,但也有用F₀表示该种子世代^[6,7,8,9,10],F₀自交产生F₁。

远缘杂交是指植物不同种、属间的杂交,对产生新的遗传变异和物种进化具有重要意义。现在一般认为普通小麦就是约1万年前自然界的3个物种,即一粒小麦(Triticum monococcum, AA),方穗山羊草(Aegilops tauschii syn. Ae. squarosa, DD)和拟斯卑尔脱山羊草(Ae. Speltoides, BB)远缘杂交的结果^[11,12]。远缘杂交能将不同种属个体的遗传基础结合在一起,是创建植物新的遗传变异和新物种的重要途径,也是遗传学和物种进化研究的重要方法。不同种属间的杂交可通过不同的途径产生杂种,如杂交后产生种子或通过胚拯救产生杂种植株,或通过体细胞融合后培养再生杂种植株,这些杂种称为杂种一代,以F₁表示^{[13,14,15,16,17,18]}。但也有以F₀表示^{[19,20,21,22,23]},甚至在同一篇文章中利用F₀和F₁表示同一世代^{[21, 23]}。种间、属间、科间甚至科以上植物之间的嫁接(grafting)是无性繁殖方法之一,是一种距今已经超过两千年的简单实用的育种方法,是否产生基因交流的无性杂种一直颇受争议。近年来,通过 Southern、 ISSR 和RAPD等分子生物学技术证明嫁接后砧木(rootstock)和接穗(scion)间发生了遗传物质的交流^[24,25,26]。辣椒嫁接诱导的果形等变异可通过种子而稳定地遗传,嫁接成功的当代植株及其接穗上的果实记为G^[27,28]或T₁^[29]。

利用植物某种器官的体细胞或性细胞进行组织培养产生后代,是通过脱分化产生愈伤组织及愈伤组织的再分化产生再生植株(regeneration plant)。由于再生植株是通过有丝分裂而产生,理论上该植株的遗传组成和供体相同。如在培养过程利用物理或化学方法诱导基因突变,产生的再生植株将存在变异,其突变位点的基因型为杂合,遗传组成就不同于供体。培养过程即使不进行基因突变诱导,但培养基中多种化学试剂可能诱导基因产生变异,导致获得的再生植株遗传组成不同于供体。如何表示这些再生植株呢?不同作者利用了不同的符号。例如,从水稻愈伤组织获得再生苗的自交后代就发生了株型变异,并以D₂表示再生苗的自交后代^[30]。但也有以R₁^[31]和R₀^[32]表示水稻愈伤组织分化的再生植株,使用的符号明显不同。还有用R₀表示组织培养产生的拟南芥和玉米再生植株^[33,34],也有以R表示油菜的再生植株^[35]。通过小麦与高冰草属间体细胞融合产生了杂种植株,从该不育植株的子房诱导的愈伤组织再生植株以F₀表示,由再生植株自交产生的种子记为F₁^[20]。

遗传学除了研究遗传和变异规律之外,更重要的是利用特定的遗传变异为人类服务。人们在利用遗传变异时发现,自然产生的变异不够用,必须人工诱导生物产生突变(mutation)。用物理或化学方法诱变种子,被处理的种子以M₀表示,播种后形成的植株以M₁表示^[36,37,38],也有以M₁表示被处理种子或营养器官所长成的植株^[39]。如诱变茎尖或完整植株,诱变当代植株以M₁表示^[40,41]。除了诱变营养组织外,人们也诱变花粉或雌配子体,再利用正常的雌配子体或花粉与之进行人工授粉杂交,杂交种子以M₁表示^[42,43]。

远缘杂交使种、属间植物的不同基因组或染色体融合而产生新种质,需要较长时间才能形成可稳定遗传的个体,而转基因技术打破了不同种属间基因交流的屏障,使不同物种间可以进行单个基因的交流,这无疑是快速增加变异的一个重要途径。首例农杆菌(Agrobacterium tumefaciens)转化烟草愈伤组织获得植株的报道中没有提及世代符号^[44]。基因枪转化大豆和小麦的愈伤组织所获阳性植株以R₀表示,R₀的自交后代以R₁表示^[45,46]。经基因枪或农杆菌转化产生的转基因阳性小麦和水稻植株习惯以T₀表示^[47,48,49]。随着转基因技术的发展,人们可以不通过愈伤组织而进行转基因。拟南芥的蘸花法或其他植物的活体转化,当代转化植株以T₀表示,收获的种子以T₁表示^[50,51,52],也有以T₀表示当代转化植株和收获的种子^[53]。基因敲除可以准确地进行基因功能分析,目前用CRISPR/Cas9技术产生的当代转化植株也称为T₀^[54,55],但该群体中除存在单突变外,还存在纯合突变的类型,情况比基因导入的转化植株复杂。

2 相对统一世代符号的建议

植物遗传学中多种途径产生的杂种新世代,其相关基因位点的基因型是杂合的。换句话讲,新世代的实质是同源染色体上目标基因的基因型,真实的杂种其基因型杂合,纯合基因型就不是杂种。明确了新世代的遗传本质,对不同方法产生的新世代就能利用准确符号表示。为了纠正用不同符号表示相同来源的新世代的混乱,有必要建立使用相对统一的新世代符号的规范。现将目前各种途径产生的新世代已使用的符号和建议使用符号等汇集于表1并加以说明。

Table 1
表1
表1 植物遗传学中杂种新世代的符号
Table 1 Symbol of new hybrid generation in plant genetics

产生途径	杂合基因型来源	已使用符号	建议使用符号	符号意义
传统杂交	种内	F1, F0	F1	当代种子或植株
远缘杂交	种、属间	F1, F0	F1	当代种子或植株
嫁接	科、种、属间	T1, G	G1	当代植株或接穗的果实
组织培养	体细胞变异	R, R0, R1, D1, F0	R1	当代再生植株
基因突变	物理化学诱变	M0, M1	M1	诱变的当代种子或植株;诱变花粉后的杂交种子;诱变营养器官而产生的植株
转基因	基因导入或敲除	R0, T0, T1	T1	当代阳性植株或种子

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传统的种内杂交产生杂种新世代,利用F₁表示当代种子和该种子长成的植株。远缘杂交是种、属间的杂交,如双亲直接杂交产生种子,或双亲杂交后通过胚拯救产生植株,或双亲体细胞融合后再通过细胞培养产生植株等,这些种子或植株,其染色体来自不同的亲本,在没有染色体加倍前是杂合的,等同于传统的种内杂种新世代,利用F₁表示。通常远缘杂交的F₁在形成配子时,由于双亲染色体的同源性低,使得染色体的配对和分离异常,从而产生没有功能的配子,也就是F₁杂种不育。通过加倍F₁中双亲染色体数产生双二倍体(amphidiploid)就可克服F₁不育,如萝卜甘蓝(Raphanobrassica)^[13]和小黑麦(Secale sylvestre)^[56,57]。双二倍体的双亲染色体在减数分裂中正常配对和分离,后代通常成为比较稳定的种、属间杂种。F₁植株经染色体加倍也可能是双亲的部分染色体倍加而成为部分双二倍体(partial amphidiploid),其后代染色体数将继续发生变化,染色体数介于双亲染色体数中间类型的植株不稳定而消失,只有接近亲本染色体数目的个体才比较稳定而保留。由于部分双二倍体后代还存在大量的分离,所以人们对部分双二倍体也称为F₁,其自交后代为F₂。成功嫁接株的砧木和接穗间发生了遗传物质的交流,可以产生遗传变异,新世代就是遗传组成变化的接穗,如接穗上产生果实,其果实也不同于原来接穗上的果实,因此,为了避免同一符号表示不同来源的杂种新世代,建议以G₁表示嫁接植株和其接穗产生的果实。

理论上,利用外植体的愈伤组织产生的再生植株是通过细胞的有丝分裂和细胞分化而产生的个体,其遗传组成与外植体的母体一样。由于组织培养过程中添加了多种化学试剂,对培养的愈伤组织可能具有诱变作用,或直接利用物理、化学方法对愈伤组织进行诱变,使再生植株的遗传组成产生变异,这些植株的变异基因位点上多数也是杂合的,建议使用R₁表示再生植株,R₂表示R₁个体自交产生的后代。

物理或化学诱变产生的新世代,因同源染色体上的等位基因同时发生突变的概率很小,诱变后代的遗传组成就相当于传统杂交产生的杂种,其相关位点的基因型为杂合。现在普遍以M₀表示处理的当代种子,以M₁表示播种后形成的植株。建议诱变的种子和该种子形成的植株均以M₁ (M₁ generation)表示。诱变的对象时有不同,完整植株为M₁,诱变花粉后进行人工授粉收获的种子也以M₁表示;诱变处理营养器官而产生的当代植株以M₁表示,M₁代确定后,M₁个体自交产生M₂,M₂个体自交产生M₃。

转基因是将外源的基因转化到受体细胞内,通常受体内无此外源基因。转基因插入受体染色体是随机的,在同源染色体相同位置插入相同基因的机会微乎其微,所以,转基因产生的当代植株或种子的目标基因型是半合子(hemizygote),不同于传统杂交产生的F₁和诱变产生的M₁的基因型。目前习惯利用T₀表示当代阳性的植株。然而,从转基因新世代的基因插入位点的遗传组成来看,转基因新世代的T₀相当于杂交的F₁。为了与其他方法产生的杂种新世代一致,可用T₁表示基因导入和基因敲除转化的当代阳性植株或种子,T₁个体自交的后代为T₂。

3 结 语

根据目标位点基因型是否杂合的原则来确定新世代,就可以使用一致、简单明了的世代符号表示新世代,避免世代符号使用的随意性和混乱。植物遗传研究中人工创建的新世代即第一代,以字母加下标数字“1”为符号表示之,字母表示不同方法产生的杂种新世代。由此,种内传统杂交产生的种子或植株为F₁,远缘杂交中产生的种子或植株也为F₁,嫁接植株和其接穗产生的果实使用G₁表示。组织培养的再生植株为R₁,物理和化学诱变处理的当代种子和由其长成的植株或直接诱变的植株为M₁,通过不同方法转化的当代阳性植株或种子为T₁。第一代符号确定后,“1”代个体自交的后代用下标数字“2”表示,“2”代个体自交的后代用下标数字“3”表示,以此类推。

本文就植物遗传学中简单的世代及符号应用问题的解读和建议,将有助于遗传学教学对世代概念的明晰,根据目标位点基因型是否杂合的原则来确定不同途径产生的新世代,利用上述的符号体系来表示,可使初****有一个清晰的概念。同理,遗传学中其他的概念,尽管生物的多样性和复杂性,但仍然存在共性,善于依据共性给出界定,将有利于遗传学的学习。植物遗传学研究中需要通过不同途径人工创建新世代并对其后代进行系统探导,随时清楚研究材料的世代,将能正确预测各世代的遗传表现和根据世代特点选择正确的研究方法。研究报告中利用准确的相对统一世代符号表示,将有利于同行间的顺利交流,也体现植物遗传学的科学性和严谨性。

The authors have declared that no competing interests exist.

作者已声明无竞争性利益关系。

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A two-component transposon system based on the Ac element of maize was used as a mutagen in Arabidopsis thaliana. Transposition of a Ds element marked with a hygromycin-resistance gene was activated from four different locations in the Arabidopsis genome. The progeny of 201 plants carrying independent transposition events were screened for mutants with severe, visible phenotypes. Seven mutants were identified and four of them were analyzed genetically. Three mutations were shown to be very closely linked to a transposed copy of the element. Moreover, a mutation (alb3) causing an albino phenotype was conclusively shown to be caused by insertion of the Ds element: somatic and germinal reversion of the mutation occurred in the presence of the transposase gene but not in its absence, and in three revertants the Ds had excised from its position in the mutant line. The DNA adjacent to Ds in the mutant was isolated and it was demonstrated that revertants retained part of the 8-bp duplication caused by insertion of Ds. These experiments indicate that the Ac/Ds system can be used as an insertional mutagen in the heterologous host Arabidopsis, which will permit the isolation of genes from this species by transposon tagging.

[5] Taboada-Gaytan O, Pollak LM, Johnson LA, Fox SR, Montgomery KT . Variation among physical, compositional, and wet-milling characteristics of the F₁ generation of corn hybrids of introgressed exotic and adapted inbred lines
Cereal Chem, 2010,87(3):175-181.
URL [本文引用: 1]
Hybrids with high grain yield and higher starch, protein, or oil content are available to corn growers; however, they result from crossing adapted Corn Belt inbred lines that rarely include exotic germplasm. This study was conducted to determine whether Corn Belt lines introgressed with exotic materials from Argentina, Chile, Uruguay, Cuba, and Florida have appropriate wet-milling characteristi...

[6] Li HJ, Zhang LH, Chen L, Zheng JD, Song W, Wang BQ, Zhang DM, Zhang WY . The preliminary study on the influence of the different maize inbred lines pollen to the F₀ seed quality
J Maize Sci, 2006,14(5):35-37.
URL [本文引用: 1]
用4个不同来源的自交系花粉分别与4个母本自交系杂交,分析杂交当代子粒中蛋白质、淀粉、赖氨酸含量和百粒重的当代杂种优势.试验结果表明:当代子粒的蛋白质含量、淀粉含量、赖氨酸含量和百粒重均存在当代杂种优势.其中F0子粒中蛋白质当代杂种优势最高达54.1%.
李海军, 张丽华, 陈玲, 郑积德, 宋炜, 王宝强, 张动敏, 张文英 . 玉米F₀代子粒品质性状杂种优势的研究
玉米科学, 2006,14(5):35-37.
URL [本文引用: 1]
用4个不同来源的自交系花粉分别与4个母本自交系杂交,分析杂交当代子粒中蛋白质、淀粉、赖氨酸含量和百粒重的当代杂种优势.试验结果表明:当代子粒的蛋白质含量、淀粉含量、赖氨酸含量和百粒重均存在当代杂种优势.其中F0子粒中蛋白质当代杂种优势最高达54.1%.

[7] Su XH, Xia ZL, Li CH . Advances in studies on heterosis of F₀ generation in maize
J Maize Sci, 2008,16(1):44-46, 51.
[本文引用: 1]

苏新宏, 夏宗良, 李潮海 . 玉米杂交当代优势研究进展
玉米科学, 2008,16(1):44-46, 51.
[本文引用: 1]

[8] Ilyas M, Naveed M, Khan TM, Khan IA . Combining ability studies in some quantitative and qualitative traits of
Gossypium hirsutum L. J Agric Soc Sci, 2007,3(2):39-42.
[本文引用: 1]

[9] Imran M, Shakeel A, Azhar FM, Farooq J, Saleem MF, Saeed A, Nazeer W, Riaz M, Naeem M, Javaid A . Combining ability analysis for within-boll yield components in upland cotton (Gossypium hirsutum L.)
Genet Mol Res, 2012,11(3):2790-2800.
URLPMID:23007974 [本文引用: 1]
Cotton is an important cash crop worldwide, accounting for a large percentage of world agricultural exports; however, yield per acre is still poor in many countries, including Pakistan. Diallel mating system was used to identify parents for improving within-boll yield and fiber quality parameters. Combining ability analysis was employed to obtain suitable parents for this purpose. The parental genotypes CP-15/2, NIAB Krishma, CIM-482, MS-39, and S-12 were crossed in complete diallel mating under green house conditions during 2009. The F seed of 20 hybrids and five parents were planted in the field in randomized complete block design with three replications during 2010. There were highly significant differences among all F hybrids and their parents. Specific combining ability (SCA) variance was greater than general combining ability (GCA) variance for bolls per plant (9.987), seeds per boll (0.635), seed density (5.672), lint per seed (4.174), boll size (3.69), seed cotton yield (0.315), and lint percentage (0.470), showing predominance of non-additive genes; while seed volume (3.84) was controlled by additive gene action based on maximum GCA variance. Cultivar MS-39 was found to be the best general combiner for seed volume (0.102), seeds per boll (0.448), and lint per seed (0.038) and its utilization produced valuable hybrids, including MS-39 x NIAB Krishma and MS-39 x S-12. The parental line CIM-482 had high GCA effects for boll size (0.33) and seeds per boll (0.90). It also showed good SCA with S-12 and NIAB Krishma for bolls per plant, with CP- 15/2 for boll size, and with MS-39 for seeds per boll. The hybrids, namely, CP-15/2 x NIAB Krishma, NIAB Krishma x S-12, NIAB Krishma x CIM-482, MS-39 x NIAB Krishma, MS-39 x CP-15/2, and S-12 x MS-39 showed promising results. Correlation analysis revealed that seed cotton yield showed significant positive correlation with bolls per plant, boll size and seeds per boll while it showed negative correlation with lint percentage and lint per seed. Seed volume showed significant negative correlation with seed density. Seeds per boll were positively correlated with boll size and negatively correlated with bolls per plant lint percentage and lint per seed. Similarly, lint per seed exhibited positive correlation with lint percentage and boll size showed significantly negative correlation with bolls per plant. Presence of non-additive genetic effects in traits like bolls per plant, seeds per boll, lint per seed, seed cotton yield, and lint percentage is indicative of later generation selection or heterosis breeding may be adopted. For boll size, seed volume and seed density early generation selection may be followed because of the presence of additive gene action. The parental material used in this study and cross combinations obtained from these parents may be exploited in future breeding endeavors.

[10] Abo-youssef M, EL Sabagh A, Abo-gendy G, Mohamed A . Enhancing seed yield of hybrid rice by maintaining row ratio and dosages of gibberellic acid
Cercet Agronom Mol, 2017,50(1):31-45.
URL [本文引用: 1]
The purpose of this study was to identify the optimum levels of gibberellic acid and suitable row ratio for maximization the seed yield of hybrid rice. An experiment was conducted at the experimental farm of Rice Research and Training Center, Egypt, during 2013 and 2014 growing seasons. The material under this study included the parental lines of IR69625A (Female lines) and Giza 179 R (Restorer line) to produce F0 hybrid seeds. A split-plot design with three replications was used. The main plot was row ratio (2R:8A, 2R:10A and 2R:12A) and sub plots was the doses of gibberellic acid (g/ha) (control, 300, 350, 400). The results indicated that, Application of GA3and row ratio had significant effect on different traits of seed yield and hybrid seed production. The highest values of flag leaf area, panicle length, seed set, panicle weight, panicle exsertion and seed yield were acheived by using 2R: 8A row ratio and was observed the lowest values were obtained at the 2:12 row ratio. Acoording to gibberellic acid application, the highest values for panicle length (cm), seed set (%), panicle weight (g), panicle exertion (%), harvest index and seed yield were recorded by using 400 g /ha gibberellic acid. Accordingly, the highest net economic return from seed yield was obtained with the treatment combination of 400 g/ha GA3x 2:8 (R: A) row ratio.

[11] Shewry PR . Wheat
J Exp Bot, 2009,60(6):1537-1553.
URL [本文引用: 1]

[12] Marcussen T, Sandve SR, Heier L, Spannagl M, Pfeifer M , International Wheat Genome Sequencing Consortium, Jakobsen KS, Wulff BB, Steuernagel B, Mayer KF, Olsen OA. Ancient hybridizations among the ancestral genomes of bread wheat
Science, 2014,345(6194):1250092.
URLPMID:25035499 [本文引用: 1]
Abstract The allohexaploid bread wheat genome consists of three closely related subgenomes (A, B, and D), but a clear understanding of their phylogenetic history has been lacking. We used genome assemblies of bread wheat and five diploid relatives to analyze genome-wide samples of gene trees, as well as to estimate evolutionary relatedness and divergence times. We show that the A and B genomes diverged from a common ancestor ~7 million years ago and that these genomes gave rise to the D genome through homoploid hybrid speciation 1 to 2 million years later. Our findings imply that the present-day bread wheat genome is a product of multiple rounds of hybrid speciation (homoploid and polyploid) and lay the foundation for a new framework for understanding the wheat genome as a multilevel phylogenetic mosaic. Copyright 2014, American Association for the Advancement of Science.

[13] Karpechenko GD . Hybrids ofRaphanus sativus L. x♂ Brassica oleracea L
J Genet, 1924,14(3):375-396.
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[14] Li MS, Suo YY, Zhou CJ . Study on culture in vitro of hybrid embryos between Chinese cabbage and radish
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李明山, 索玉英, 周长久 . 大白菜与萝卜属间杂种幼胚离体培养的研究
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[15] Yuan HM, Wang XL, Chen DS, Sun JC, Fan JP, Zhang FG, Zhao GZ . Study on F₁ phenotype of wheat crosses involving wild relatives and triticale
J Plant Genet Resour, 2005,6(4):377-380, 385.
[本文引用: 1]

袁汉民, 王小亮, 陈东升, 孙建昌, 范金萍, 张富国, 赵桂珍 . 普通小麦远缘杂交F₁代表现型研究
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[16] Ren SJ, Wang MJ, Huang F, He LJ, Bai CL . Identification and karyotype analysis of offspring of F₁ hybrids to two kinds of clover
Anim Husb Feed Sci, 2014,35(6):16-21.
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任尚佳, 王明玖, 黄帆, 何丽君, 白春利 . 2种三叶草杂种F₁代后代鉴定及核型分析
畜牧与饲料科学, 2014,35(6):16-21.
[本文引用: 1]

[17] Han SY, Zhou GP, Wang XH, Zhang F . Botanical traits of distant hybridization F₁ between Morus cathayana x Mulberry cultivation varieties
Guizhou Agric Sci, 2016,44(11):7-11.
URL [本文引用: 1]
为华桑与桑树栽培品种远缘杂交F1代的应用提供参考,对其正反交共10个远缘杂交组合（华桑种为贵88号,栽培桑品种为云桑1号、转阁楼、桐乡青、盛南和澧桑24号）F1代植物学性状进行调查分析。结果表明：华桑与桑树栽培品种远缘杂交遗传具有丰富性和多样性。其中,亲本为全叶的杂交组合中,华桑×桑树栽培品种和桑树栽培品种×华桑的F1代有裂叶的比例平均为16.10%和17.04%;亲本均无椭圆形叶,但F1代出现的比例平均为43.61%和19.59%;亲本无卵圆形叶的杂交组合中,F1代出现的比例平均为19.06%和19.75%;亲本叶缘无乳头锯齿的杂交组合中,F1代叶缘出现的比例平均为21.05%和27.57%;亲本叶缘均无谷针锯齿,但F1代出现的比例平均为8.71%和7.14%;亲本无弯曲枝态,但F1代出现的比例平均为47.91%和21.13%;亲本无折曲节间的组合中,F1代出现的比例平均为26.89%和21.14%。
韩世玉, 周光萍, 王晓红, 张芳 . 华桑与桑树栽培品种远缘杂交F₁代的植物学性状
贵州农业科学, 2016,44(11):7-11.
URL [本文引用: 1]
为华桑与桑树栽培品种远缘杂交F1代的应用提供参考,对其正反交共10个远缘杂交组合（华桑种为贵88号,栽培桑品种为云桑1号、转阁楼、桐乡青、盛南和澧桑24号）F1代植物学性状进行调查分析。结果表明：华桑与桑树栽培品种远缘杂交遗传具有丰富性和多样性。其中,亲本为全叶的杂交组合中,华桑×桑树栽培品种和桑树栽培品种×华桑的F1代有裂叶的比例平均为16.10%和17.04%;亲本均无椭圆形叶,但F1代出现的比例平均为43.61%和19.59%;亲本无卵圆形叶的杂交组合中,F1代出现的比例平均为19.06%和19.75%;亲本叶缘无乳头锯齿的杂交组合中,F1代叶缘出现的比例平均为21.05%和27.57%;亲本叶缘均无谷针锯齿,但F1代出现的比例平均为8.71%和7.14%;亲本无弯曲枝态,但F1代出现的比例平均为47.91%和21.13%;亲本无折曲节间的组合中,F1代出现的比例平均为26.89%和21.14%。

[18] He Q, Deng HF, Shu F, Zhang WH . Present status on utilization of distant hybridization and heterosis in rice
J Agric Sci Technol, 2007,9(5):24-29.
[本文引用: 1]

何强, 邓华凤, 舒服, 张武汉 . 水稻远缘杂交及杂种优势利用现状
中国农业科技导报, 2007,9(5):24-29.
[本文引用: 1]

[19] Li SH, Sun QH . Studies on increase of plantlet formation percentage of rice young embry culture
.Ningxia J Agric Fore Sci Technol, 1995(4):3-6.
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李树华, 孙庆合 . 提高水稻幼胚培养成苗率的研究
宁夏农林科技, 1995(4):3-6.
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[20] Xia GM, Xiang FN, Zhou AF, Wang H, He SX, Chen HM . Fertile hybrid plant regeneration from somatic hybridization betweenTriticum aestivum and Agropyron elongatum
Acta Bot Sin, 1999,41(4):349-352.
URL [本文引用: 2]
普通小麦“济南１７７”与紫外线照射的高冰草原生质体在ＰＥＧ诱导下融合，获杂种再生植株。取杂种子房诱导产生愈伤组织并再生植株，经染色体和同工酶鉴定，它们仍保留杂种性质。其中两株移栽成活并结实，杂种性质也经表型，染色体，同工酶和ＲＡＰＤ分析得到证明。在Ｆ０和Ｆ１代植株根尖细胞中，均发现高频率也存在着染色体断片。从Ｆ２代花粉母细胞减数分裂的染色体数目及行为发现，杂种细胞染色体数目主要分布在１８Ⅱ￣２２Ⅱ
夏光敏, 向凤宁, 周爱芬, 王槐, 何世贤, 陈惠民 . 小麦与高冰草属间体细胞杂交获可育杂种植株
植物学报, 1999,41(4):349-352.
URL [本文引用: 2]
普通小麦“济南１７７”与紫外线照射的高冰草原生质体在ＰＥＧ诱导下融合，获杂种再生植株。取杂种子房诱导产生愈伤组织并再生植株，经染色体和同工酶鉴定，它们仍保留杂种性质。其中两株移栽成活并结实，杂种性质也经表型，染色体，同工酶和ＲＡＰＤ分析得到证明。在Ｆ０和Ｆ１代植株根尖细胞中，均发现高频率也存在着染色体断片。从Ｆ２代花粉母细胞减数分裂的染色体数目及行为发现，杂种细胞染色体数目主要分布在１８Ⅱ￣２２Ⅱ

[21] Wang SY, Yun JF, Li L, Zhu L . Barriers and fertility restoration of widecross hybrids of perennial herb in Triticeae
Grassl China, 2003,25(2):59-62.
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远缘杂交是改良植物种质的有效手段之一,但植物自身有保持物种稳定性的遗传屏障,针对不同植物的杂交障碍应采取不同的克服不育的方法.
王树彦, 云锦凤, 李莉, 朱琳 . 禾本科小麦族植物远缘杂交的障碍及其克服
中国草地, 2003,25(2):59-62.
URL [本文引用: 2]
远缘杂交是改良植物种质的有效手段之一,但植物自身有保持物种稳定性的遗传屏障,针对不同植物的杂交障碍应采取不同的克服不育的方法.

[22] Gao Q, Wang HL, Zheng J, Li JG . Effects of different combination on hybrid seed yield of triploid watermelon
China Cucur Veget, 2014,27(2):8-11, 15.
[本文引用: 1]

高强, 王惠林, 郑健, 李俊阁 . 不同组合对三倍体西瓜F₀代单瓜可育种子数量的影响
中国瓜菜, 2014,27(2):8-11, 15.
[本文引用: 1]

[23] Ruan RW, Fu DX, Dai XM . Analysis of heterosis and heredity of main yield characters in wheat
J Southwest Agric Univ, 2002,24(1):141-145.
URL [本文引用: 2]
选用5个小麦品种,按GriffingⅡ进行完全双列杂交,研究了株粒重、株有效穗数、穗粒数、千粒重和株高等5个性状的杂种优势和遗传特性,按朱军提出的杂种优势新的分析方法,估算F2代基因型的杂种优势.结果表明:株粒重、千粒重和株高的F1,F2代基因型有显著的群体平均优势,株有效穗数群体平均优势不显著,穗粒数表现为负优势,所有性状群体超亲优势不显著,千粒重和株高的加性效应方差显著,株粒重、穗粒数和千粒重的显性效应方差显著,株粒重和穗粒数主要受显性效应的影响,株高主要受加性效应的影响,千粒重则受加性效应和显性效应共同影响,株有效穗数则受显性效应和环境的影响.F1,F2代株高的群体超亲优势与显性效应相关不显著外,其他性状均达显著相关,F1代各性状与F2代各性状的群体超亲优势之间均达极显著相关,表明小麦的杂种优势可以利用F2代.
阮仁武, 傅大雄, 戴秀梅 . 小麦主要产量性状的杂种优势和遗传分析
西南农业大学学报, 2002,24(1):141-145.
URL [本文引用: 2]
选用5个小麦品种,按GriffingⅡ进行完全双列杂交,研究了株粒重、株有效穗数、穗粒数、千粒重和株高等5个性状的杂种优势和遗传特性,按朱军提出的杂种优势新的分析方法,估算F2代基因型的杂种优势.结果表明:株粒重、千粒重和株高的F1,F2代基因型有显著的群体平均优势,株有效穗数群体平均优势不显著,穗粒数表现为负优势,所有性状群体超亲优势不显著,千粒重和株高的加性效应方差显著,株粒重、穗粒数和千粒重的显性效应方差显著,株粒重和穗粒数主要受显性效应的影响,株高主要受加性效应的影响,千粒重则受加性效应和显性效应共同影响,株有效穗数则受显性效应和环境的影响.F1,F2代株高的群体超亲优势与显性效应相关不显著外,其他性状均达显著相关,F1代各性状与F2代各性状的群体超亲优势之间均达极显著相关,表明小麦的杂种优势可以利用F2代.

[24] Stegemann S, Bock R . Exchange of genetic material between cells in plant tissue grafts
Science, 2009,324(5927):649-651.
URLPMID:19407205 [本文引用: 1]
Tissue grafting includes applications ranging from plant breeding to animal organ transplantation. Donor and recipient are generally believed to maintain their genetic integrity, in that the grafted tissues are joined but their genetic materials do not mix. We grafted tobacco plants from two transgenic lines carrying different marker and reporter genes in different cellular compartments, the nucleus and the plastid. Analysis of the graft sites revealed the frequent occurrence of cells harboring both antibiotic resistances and both fluorescent reporters. Our data demonstrate that plant grafting can result in the exchange of genetic information via either large DNA pieces or entire plastid genomes. This observation of novel combinations of genetic material has implications for grafting techniques and also provides a possible path for horizontal gene transfer.

[25] Zhou ZL, Tang J, Zhang YG, Zhao DL . Study on gene transfer between different sweet potato varieties after grafting
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周志林, 唐君, 张允刚, 赵冬兰 . 嫁接后甘薯品种间基因渗透的研究
江西农业学报, 2009,21(8):17-18.
[本文引用: 1]

[26] Chen H, Wang YQ . RAPD analysis of tissues of grafting union in tomato and eggplant
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以一个与甘蓝显性核不育相关的差异表达片段序列为信息探针, 在NCBI与TAIR网站数据库中进行同源EST序列搜索, 经人工拼接、RT - PCR克隆与序列分析验证, 获得了青花菜快速碱化因子RALF(Rapid Alkalinization Factors) 基因的cDNA全长序列, 命名为<EM>BoRALFL</EM>1 (GenBank序列登录号DQ059310)。该cDNA全长240 bp, 编码79个氨基酸, 与电子克隆获得的序列完全相同。序列分析表明, 编码蛋白存在前导信号肽与多个磷酸化位点, 与同源基因RALFL8核酸序列在88 bp上有82%的一致性, 推导的氨基酸序列在74个氨基酸上存在56%的一致性, 不同植物间氨基酸序列N - 端差异大, C - 端具有较高的保守性。
陈红, 王永清 . 番茄与茄子嫁接接合部愈伤组织的RAPD分析
园艺学报, 2006,33(3):565.
URLMagsci [本文引用: 1]
以一个与甘蓝显性核不育相关的差异表达片段序列为信息探针, 在NCBI与TAIR网站数据库中进行同源EST序列搜索, 经人工拼接、RT - PCR克隆与序列分析验证, 获得了青花菜快速碱化因子RALF(Rapid Alkalinization Factors) 基因的cDNA全长序列, 命名为<EM>BoRALFL</EM>1 (GenBank序列登录号DQ059310)。该cDNA全长240 bp, 编码79个氨基酸, 与电子克隆获得的序列完全相同。序列分析表明, 编码蛋白存在前导信号肽与多个磷酸化位点, 与同源基因RALFL8核酸序列在88 bp上有82%的一致性, 推导的氨基酸序列在74个氨基酸上存在56%的一致性, 不同植物间氨基酸序列N - 端差异大, C - 端具有较高的保守性。

[27] Taller J, Yagishita N, Hirata Y . Graft-induced variants as a source of novel characteristics in the breeding of pepper (Capsicum annuum L.)
Euphytica, 1999,108(2):73-78.
URL [本文引用: 1]
A line with genetic changes that was obtained from selfed seeds of the scion of an intraspecific pepper graft was used as a source of new characteristics in this breeding experiment. Five new variant lines and several sublines were bred by the use of this graft-induced variant strain and two other cultivars. Gradual introduction of the desired quantitative traits and selection resulted in combinations which significantly outperform the parental lines. Our breeding aim was to combine the two-lobed fruit shape that is characteristic for the graft-induced variants with thick pericarp, high sugar content, large fruit size, and significantly reduced or eliminated pungency in the new variants. A bushy plant type, typical for the graft-induced variants could be maintained in some selected sublines. The use of the three different genotypes resulted in many favorable combinations of quantitative traits, and lines were selected with the most valuable new characteristics. However, not all of these expressed the two-lobed fruit apex of the graft-induced variants. Our results reveal that the new characteristics which are induced by grafting are stable, new traits, and can be used as a novel genetic source in the breeding of pepper.

[28] Taller J, Hirata Y, Yagishita N, Kita M, Ogata S . Graft- induced genetic changes and the inheritance of several characteristics in pepper (Capsicum annuum L.)
Theor App Genet, 1998,97(5-6):705-713.
URL [本文引用: 1]
The general characteristics of several graft-induced changes in pepper were investigated in a cross experiment. F 1 , F 2 , and BC 1 progenies derived from crosses of the original stock and scion cultivars ‘Spanish Paprika’ and ‘Yatsubusa’, respectively, as well as their graft-induced variant strain G 5 S 25 were analyzed for inheritance of the most conspicuous graft-induced variant traits. As part of a research program with the aim of revealing the mechanism of graft induction, the present study was carried out to examine the stability of the phenotypic changes and the characteristics of the graft-induced variants. For the fruit apex, a two-gene system was suggested, with other factors having a modifying influence. One of the two apex genes acted for pointed fruits and the other for inverted-blunt fruits. The inverted-blunt gene, the apex gene of the stock, was unambiguously present in the graft-induced variants, while the pointed gene that acted in the dominant mode in the original scion was inactive and expressed only under certain conditions in a mosaic state. The stable inverted-blunt cultivar used for the stock maintained certain factor(s) for pointed fruit, but the presence of that factor(s) could not be detected in graft-induced variants. The results of pungency analysis suggested a gene for non-pungency that appeared to be introduced in the graft-induced variants. The fruiting habit and fruiting direction that appeared in a mosaic state in graft-induced variants were found to combine factors of the stock with the appropriate characteristics of the scion asymmetrically. The bushy plant type appeared in a transgressive state in the variants, showing a definitely higher number of branches on the main stem and more frequent ramifications on the complete plant than on either the stock and scion cultivars or the progency derived from sexual crosses. A change in mature fruit color from red to yellow occurred in an early generation of graft-induced variants. Our results demonstrate that some of the characteristics of the stock were introduced into the progeny obtained from selfed seeds of the scion and that novel characteristics appeared as a result of graft induction.

[29] Tsaballa A, Athanasiadis C, Pasentsis K, Ganopoulos I, Nianiou-Obeidat I, Tsaftaris A . Molecular studies of inheritable grafting induced changes in pepper (Capsicum annuum) fruit shape
Sci Hortic, 2013,149:2-8.
URL [本文引用: 1]
Vegetable grafting is used extensively today by farmers primarily for facing soil borne problems – among other benefits – despite some unfavorable fruit quality effects observed in certain rootstock-scion combinations. Fruit shape is a characteristic known to be affected by grafting. Herein, working with pepper graftings between two pepper genotypes (cultivars) differing in fruit shape, we observed fruit shape changes after grafting the round shaped cultivar, cv. “Mytilini Round” (scion) on the long shaped cultivar, cv. “Piperaki Long” (rootstock). Furthermore, the phenotypic changes observed in scion fruits were inherited for two generations of seed derived progenies indicating that the changes imposed on scion are heritable. PCR amplifications using six inter simple sequence repeat (ISSR) primers showed that progenies developed from seeds collected from the modified scion fruits had a genetic profile more similar to the scion genetic profile and less similar to the rootstock profile indicating that only minor genetic changes occurred in the scion during grafting. The change in the fruit shape was not found to be accompanied by extended DNA sequence changes in pepper CaOvate sequence, a gene shown before to be involved in determining fruit shape in pepper, although a slight difference in CaOvate gene expression was found. Overall, understanding the molecular mechanisms that probably underline graft-induced changes paves the way to a better knowledge over the rootstock-scion interactions, the role of rootstock in scion performance and eventually the improved quality and fruit harvest from grafted vegetable plants.

[30] Fu SY, Yu PT, Zhang P, Li H . Transplantation and D₂ analysis of regenerated rice plantlets from tissue culture
Acta Agric Univ Jiangxi, 1991,13(4):362-365.
[本文引用: 1]

傅世耀, 余沛涛, 张平, 李宏 . 水稻组织培养再生植株的移土栽培及D₂代分析
江西农业大学学报, 1991,13(4):362-365.
[本文引用: 1]

[31] Sun JH, She JM, Lü XF . Selection of mutants of
Xanthomonas oryzae by tissue culture in rice. I. In vitro induction and screening mutants resistant to Xanthornonas oryzae from callus culture in rice. Acta Genet Sin, 1986,13(3):188-193.
Magsci [本文引用: 1]
选用感病品种南粳34去壳籽粒的愈伤组织，接种白叶枯病病原菌菌株Ks 8--4， 共同培<BR>养，以期筛选抗菌愈伤组织。在365块接菌愈伤组织中，有63块局部生长，从中得到抗菌新愈伤组织“ 块，并分化出再生植株。鉴定再生植株当代R,45株，有44株抗病，1株感病。部分株系得到了R2, R3代植株，多代鉴定表明，其抗病性是稳定的和可遗传的。
孙立华, 佘建明, 吕学锋 . 用组织培养法筛选水稻抗白叶枯病突变体I.水稻愈伤组织抗白叶枯病病原菌的选择及其再生植株的抗病性鉴定
遗传学报, 1986,13(3):188-193.
Magsci [本文引用: 1]
选用感病品种南粳34去壳籽粒的愈伤组织，接种白叶枯病病原菌菌株Ks 8--4， 共同培<BR>养，以期筛选抗菌愈伤组织。在365块接菌愈伤组织中，有63块局部生长，从中得到抗菌新愈伤组织“ 块，并分化出再生植株。鉴定再生植株当代R,45株，有44株抗病，1株感病。部分株系得到了R2, R3代植株，多代鉴定表明，其抗病性是稳定的和可遗传的。

[32] Yuan YX, Wan ZG, Sun BY . Regeneration of rice mutants harbouring Ac/Ds elements via tissue culture
Seed, 2009,28(2):9-11.
URL [本文引用: 1]
用含Ac/D s转座元件的水稻种子为实验材料,从成熟胚盾片诱导愈伤组织,并经分化培养获得一定量的再生植株(R0),经田间栽培收获再生植株的成熟种子(R1)。对获得的111株再生植株(R0)叶片取样,提取基因组DNA,采用PCR方法检测其Ac/D s插入。结果表明,有94%的再生植株含有Ac/D s,6%的再生植株仅含Ac。只带有Ac而无D s的再生植株是由于D s切离而丢失,其具体机制目前还不清楚,有待进一步研究。因此,利用组织培养的方法获得更多的突变体来构建突变体库是可行的。
袁云香, 万志刚, 孙丙耀 . 水稻Ac/Ds组织培养获得再生植株突变体
种子, 2009,28(2):9-11.
URL [本文引用: 1]
用含Ac/D s转座元件的水稻种子为实验材料,从成熟胚盾片诱导愈伤组织,并经分化培养获得一定量的再生植株(R0),经田间栽培收获再生植株的成熟种子(R1)。对获得的111株再生植株(R0)叶片取样,提取基因组DNA,采用PCR方法检测其Ac/D s插入。结果表明,有94%的再生植株含有Ac/D s,6%的再生植株仅含Ac。只带有Ac而无D s的再生植株是由于D s切离而丢失,其具体机制目前还不清楚,有待进一步研究。因此,利用组织培养的方法获得更多的突变体来构建突变体库是可行的。

[33] Jiang CF, Mithani A, Gan XC, Belfield EJ, Klingler JP, Zhu JK, Ragoussis J, Mott R, Harberd NP . RegenerantArabidopsis lineages display a distinct genome-wide spectrum of mutations conferring variant phenotypes
Curr Biol, 2011,21(16):1385-1390.
URLPMID:21802297 [本文引用: 1]
Multicellular organisms can be regenerated from totipotent differentiated somatic cell or nuclear founders []. Organisms regenerated from clonally related isogenic founders might a priori have been expected to be phenotypically invariant. However, clonal regenerant animals display variant phenotypes caused by defective epigenetic reprogramming of gene expression [2], and clonal regenerant plants exhibit poorly understood heritable phenotypic (“somaclonal”) variation []. Here we show that somaclonal variation in regenerant Highlights? Regenerant Arabidopsis lineages display heritable phenotypic variation ? Regenerant Arabidopsis lineages display elevated genome-wide DNA sequence mutation ? Regenerant DNA sequence mutations comprise a distinct molecular spectrum ? Regenerant base substitution mutations confer heritable phenotypic variation

[34] Stelpflug SC, Eichten SR, Hermanson PJ, Springer NM, Kaeppler SM . Consistent and heritable alterations of DNA methylation are induced by tissue culture in maize
Genetics, 2014,198(1):209-218.
URLPMID:25023398 [本文引用: 1]
Plants regenerated from tissue culture and their progenies are expected to be identical clones, but often display heritable molecular and phenotypic variation. We characterized DNA methylation patterns in callus, primary regenerants, and regenerant-derived progenies of maize using immunoprecipitation of methylated DNA (meDIP) to assess the genome-wide frequency, pattern, and heritability of DNA methylation changes. Although genome-wide DNA methylation levels remained similar following tissue culture, numerous regions exhibited altered DNA methylation levels. Hypomethylation events were observed more frequently than hypermethylation following tissue culture. Many of the hypomethylation events occur at the same genomic sites across independent regenerants and cell lines. The DNA methylation changes were often heritable in progenies produced from self-pollination of primary regenerants. Methylation changes were enriched in regions upstream of genes and loss of DNA methylation at promoters was associated with altered expression at a subset of loci. Differentially methylated regions (DMRs) found in tissue culture regenerants overlap with the position of naturally occurring DMRs more often than expected by chance with 8% of tissue culture hypomethylated DMRs overlapping with DMRs identified by profiling natural variation, consistent with the hypotheses that genomic stresses similar to those causing somaclonal variation may also occur in nature, and that certain loci are particularly susceptible to epigenetic change in response to these stresses. The consistency of methylation changes across regenerants from independent cultures suggests a mechanistic response to the culture environment as opposed to an overall loss of fidelity in the maintenance of epigenetic states.

[35] Sacristán MD . Selection for disease resistance inBrassica cultures
Hereditas, 1985,103(S3):57-63.
[本文引用: 1]

[36] Wang D, Ren SX, Li WF, Su QZ, Su J . Plant growth of E-beam irradiated or ion implanted seeds of ornamental Celosia
J Rad Res Rad Proc, 2006,24(3):188-192.
URL [本文引用: 1]
利用电子束和氮离子、氢离子注入处理普通鸡冠花干种子，试验结果表明，两种诱变处理均能显著 抑制鸡冠花植株的生长、发育，并能有效地诱发花性状变异，变异株率可达0．59%-2％。电子束处理鸡冠花干种子的半致死剂量（LD50）经测定为 1．2kGy左右；离子注入处理的半致死剂量随注入离子种类不同而不同，N^＋注入的半致死剂量（LD50）为1．6×10^17/cm^2，H^＋注入 的半致死剂量应低于1．6×10^16/cm^2。鸡冠花干种子电子束处理的适宜剂量为1．5kGy左右，离子注入处理的适宜方法是 N^＋1．6×10^16/cm^2。同时鸡冠花对高剂量辐照较不敏感，是一种耐强辐照的资源。
王丹, 任少雄, 李卫锋, 苏乾治, 苏军 . 电子束和离子注入处理鸡冠花种子对当代(M₀)植株生长发育影响的初步研究
辐射研究与辐射工艺学报, 2006,24(3):188-192.
URL [本文引用: 1]
利用电子束和氮离子、氢离子注入处理普通鸡冠花干种子，试验结果表明，两种诱变处理均能显著 抑制鸡冠花植株的生长、发育，并能有效地诱发花性状变异，变异株率可达0．59%-2％。电子束处理鸡冠花干种子的半致死剂量（LD50）经测定为 1．2kGy左右；离子注入处理的半致死剂量随注入离子种类不同而不同，N^＋注入的半致死剂量（LD50）为1．6×10^17/cm^2，H^＋注入 的半致死剂量应低于1．6×10^16/cm^2。鸡冠花干种子电子束处理的适宜剂量为1．5kGy左右，离子注入处理的适宜方法是 N^＋1．6×10^16/cm^2。同时鸡冠花对高剂量辐照较不敏感，是一种耐强辐照的资源。

[37] Parry MA, Madgwick PJ, Bayon C, Tearall K, Hernandez-Lopez A, Baudo M, Rakszegi M, Hamada W, Al-Yassin A, Ouabbou H, Labhilili M, Phillips AL . Mutation discovery for crop improvement
J Exp Bot, 2009,60(10):2817-2825.
URLPMID:19516074 [本文引用: 1]
Increasing crop yields to ensure food security is a major challenge. Mutagenesis is an important tool in crop improvement and is free of the regulatory restrictions imposed on genetically modified organisms. The forward genetic approach enables the identification of improved or novel phenotypes that can be exploited in conventional breeding programmes. Powerful reverse genetic strategies that allow the detection of induced point mutations in individuals of the mutagenized populations can address the major challenge of linking sequence information to the biological function of genes and can also identify novel variation for plant breeding. This review briefly discusses recent advances in the detection of mutants and the potential of mutagenesis for crop improvement.

[38] Jia SG, Li XA, Morton K, Avoles-Kianian P, Kianian SF, Zhang C, Holding D . A population of deletion mutants and an integrated mapping and exome-seq pipeline for gene discovery in maize
Gene, Genom, Genet, 2016,6(8):2385-2395.
URLPMID:4978893 [本文引用: 1]
To better understand maize endosperm filling and maturation, we used -irradiation of the B73 maize reference line to generate mutants with opaque endosperm and reduced kernel fill phenotypes, and created a population of 1788 lines including 39 Mo17 F2s showing stable, segregating, and viable kernel phenotypes. For molecular characterization of the mutants, we developed a novel functional genomics platform that combined bulked segregant RNA and exome sequencing (BSREx-seq) to map causative mutations and identify candidate genes within mapping intervals. To exemplify the utility of the mutants and provide proof-of-concept for the bioinformatics platform, we present detailed characterization of line 937, an opaque mutant harboring a 6203 bp in-frame deletion covering six exons within theOpaque-1gene. In addition, we describe mutant line 146 which contains a 4.8 kb intragene deletion within theSugary-1gene and line 916 in which an 8.6 kb deletion knocks out aCyclin A2gene. The publically available algorithm developed in this work improves the identification of causative deletions and its corresponding gaps within mapping peaks. This study demonstrates the utility of -irradiation for forward genetics in large nondense genomes such as maize since deletions often affect single genes. Furthermore, we show how this classical mutagenesis method becomes applicable for functional genomics when combined with state-of-the-art genomics tools.

[39] Shi HC, Li Q, Ke YP, Yuan JC, Yu XJ, Cao LZ, Lang DF . Effects of ⁶⁰Co-γ ray irradiation mutation on maize inbred lines R08 and 48-2
Southwest China J of Agric Sci, 2011,24(5):1836-1641.
URL [本文引用: 1]
用3种不同剂量60Co-γ射线辐射处理2个玉米自交系种子,对其诱变后代M1生物学效应及其M3株系主要性状的变异进行了分析。结果表明：①2个玉米自交系M1植株均受到明显的抑制及辐射损伤,具体表现在,株高和穗位高降低,叶面积减小,并且这种抑制损伤效应随着辐射剂量的增加而增大;它们的M1雄穗长和雄穗分枝数均降低;低剂量处理就能引起RO8的穗长和48-2的穗行数在M1代产生较大变化。②诱变后代M3株系各性状出现不同程度的正向突变和负向突变,其中株高、穗位高及叶面积平均值与对照有显著差异的M3株系频率高于主要雄穗及果穗性状,说明这些性状的诱变效果更好;诱变后代各性状的变异幅度和变异系数增大,表明辐射诱变能扩大玉米主要性状的变异谱,拓宽选择范围。此外,在48-2的M3代还获得了2个籽粒颜色发生突变的株系和2个雄性不育突变株系。
石海春, 李奇, 柯永培, 袁继超, 余学杰, 曹林志, 梁德凤 . ⁶⁰Co-γ射线对自交系R08和48-2的诱变效应
西南农业学报, 2011,24(5):1836-1641.
URL [本文引用: 1]
用3种不同剂量60Co-γ射线辐射处理2个玉米自交系种子,对其诱变后代M1生物学效应及其M3株系主要性状的变异进行了分析。结果表明：①2个玉米自交系M1植株均受到明显的抑制及辐射损伤,具体表现在,株高和穗位高降低,叶面积减小,并且这种抑制损伤效应随着辐射剂量的增加而增大;它们的M1雄穗长和雄穗分枝数均降低;低剂量处理就能引起RO8的穗长和48-2的穗行数在M1代产生较大变化。②诱变后代M3株系各性状出现不同程度的正向突变和负向突变,其中株高、穗位高及叶面积平均值与对照有显著差异的M3株系频率高于主要雄穗及果穗性状,说明这些性状的诱变效果更好;诱变后代各性状的变异幅度和变异系数增大,表明辐射诱变能扩大玉米主要性状的变异谱,拓宽选择范围。此外,在48-2的M3代还获得了2个籽粒颜色发生突变的株系和2个雄性不育突变株系。

[40] Zhang ZW, Wang D . Effect of electron beam irradiation on growth and development of induced Gladiolus
J Northeast For Univ, 2008,36(1):26-27.
URL [本文引用: 1]
为了探讨电子束对唐菖蒲诱变育种的可行性和不同剂量的电子束对植株生长发育的影响,用能量为3MeV的电子束辐照唐菖蒲"江山美人"和"超级玫瑰"球茎。在苗期及初花期,电子束诱变处理有显著抑制植株的生长和发育的趋势。在初花期,随着剂量的增大,唐菖蒲"超级玫瑰"细胞间隙CO2体积分数和光合速率均受到刺激作用而增大(P0.05);唐菖蒲对电子束辐照的半致死剂量在品种间存在差异,"江山美人"比"超级玫瑰"有更强的电子束耐受性;电子束处理唐菖蒲"超级玫瑰"球茎的半致死剂量(LD50)应为240 Gy,"江山美人"的半致死剂量(LD50)则大于240 Gy。
张志伟, 王丹 . 电子束处理对唐菖蒲M₁代植株生长发育的影响
东北林业大学学报, 2008,36(1):26-27.
URL [本文引用: 1]
为了探讨电子束对唐菖蒲诱变育种的可行性和不同剂量的电子束对植株生长发育的影响,用能量为3MeV的电子束辐照唐菖蒲"江山美人"和"超级玫瑰"球茎。在苗期及初花期,电子束诱变处理有显著抑制植株的生长和发育的趋势。在初花期,随着剂量的增大,唐菖蒲"超级玫瑰"细胞间隙CO2体积分数和光合速率均受到刺激作用而增大(P0.05);唐菖蒲对电子束辐照的半致死剂量在品种间存在差异,"江山美人"比"超级玫瑰"有更强的电子束耐受性;电子束处理唐菖蒲"超级玫瑰"球茎的半致死剂量(LD50)应为240 Gy,"江山美人"的半致死剂量(LD50)则大于240 Gy。

[41] Chen L, Zhang WL, Zhang M, Li Z, Li L . A preliminary study on screening for drought resistant mutants of blueberry shoots with EMS mutagenesis
J Southwest China Normal Univ (Nat Sci Ed), 2010,35(3):99-102.
URL [本文引用: 1]
以两个品种越橘继代苗茎尖为试材,用甲基磺酸乙酯对其茎尖进行处理后,外植体再生率和再生株生根率比对照均有所下降.M1代植株经干旱胁迫后进行初步筛选后,过氧化氢酶、超氧化物歧化酶、过氧化物酶活性增强,丙二醛含量减少,对干旱环境表现出一定的抗性.这两组材料经浓度为0.3%甲基磺酸乙酯诱变处理后可能存在抗旱性较强的突变植株.
陈凌, 张文玲, 张敏, 李政, 李凌 . 化学诱变剂EMS筛选越橘茎尖抗旱突变体的初步研究
西南师范大学学报(自然科学版), 2010,35(3):99-102.
URL [本文引用: 1]
以两个品种越橘继代苗茎尖为试材,用甲基磺酸乙酯对其茎尖进行处理后,外植体再生率和再生株生根率比对照均有所下降.M1代植株经干旱胁迫后进行初步筛选后,过氧化氢酶、超氧化物歧化酶、过氧化物酶活性增强,丙二醛含量减少,对干旱环境表现出一定的抗性.这两组材料经浓度为0.3%甲基磺酸乙酯诱变处理后可能存在抗旱性较强的突变植株.

[42] Zhao YL, Song TM, Ma HP . The quick development of speciality corn by chemical mutagenesis of pollen
Acta Agron Sin, 1999,25(2):157-161.
URLMagsci [本文引用: 1]
采用含有化学诱变剂EMS的石蜡油，直接处理玉米自交系黄早4和7922的成熟花粉，并结合M2代突变基因的等位性测验，对花粉化学诱变创造特用玉米进行了研究。结果表明，在不同EMS处理浓度下，白色胚乳基因贝的诱变率平均为35.22‰,最高达到150.38‰, 1.67×10-3可作为EMS诱发y1基因突变的参考浓度。糖胚乳基因sul,孺胚乳基因wx1
赵永亮, 宋同明, 马惠平 . 利用花粉化学诱变快速创造特用玉米新种质
作物学报, 1999,25(2):157-161.
URLMagsci [本文引用: 1]
采用含有化学诱变剂EMS的石蜡油，直接处理玉米自交系黄早4和7922的成熟花粉，并结合M2代突变基因的等位性测验，对花粉化学诱变创造特用玉米进行了研究。结果表明，在不同EMS处理浓度下，白色胚乳基因贝的诱变率平均为35.22‰,最高达到150.38‰, 1.67×10-3可作为EMS诱发y1基因突变的参考浓度。糖胚乳基因sul,孺胚乳基因wx1

[43] Liu XL, Yang Z, Li G . Biological effects of M₁ generation by utilizing EMS mutagen on maize pollen
J Shenyang Agric Univ, 2006,37(6):806-810.
URL [本文引用: 1]
采用含有甲基磺酸乙酯(EMS)的石蜡油溶液处理玉米自交系910,7019,齐319,丹340和联87的成熟花粉,研究了经EMS处理的花粉离体萌发率与处理当代结实率的相关性及M1代生物学性状的变异。结果表明:花粉离体培养后萌发率随EMS浓度的增加而降低,并与处理当代的结实率呈正相关;EMS处理的M1代引起了较大的生理损伤和生物学变异效应,主要表现为结实率低、出苗率低、出苗持续时间长、出苗迟缓、成株率下降、M1代群体的抽雄期表现提前和延迟等特性;M1代苗期变异以叶色变异为主,其中条纹叶变异最大,而成株期以雄穗变异为主,其中雄性败育变异率最高。
刘晓丽, 杨镇, 李刚 . EMS诱变玉米花粉M₁代生物学效应研究
沈阳农业大学学报, 2006,37(6):806-810.
URL [本文引用: 1]
采用含有甲基磺酸乙酯(EMS)的石蜡油溶液处理玉米自交系910,7019,齐319,丹340和联87的成熟花粉,研究了经EMS处理的花粉离体萌发率与处理当代结实率的相关性及M1代生物学性状的变异。结果表明:花粉离体培养后萌发率随EMS浓度的增加而降低,并与处理当代的结实率呈正相关;EMS处理的M1代引起了较大的生理损伤和生物学变异效应,主要表现为结实率低、出苗率低、出苗持续时间长、出苗迟缓、成株率下降、M1代群体的抽雄期表现提前和延迟等特性;M1代苗期变异以叶色变异为主,其中条纹叶变异最大,而成株期以雄穗变异为主,其中雄性败育变异率最高。

[44] Zambryski P, Joos H, Genetello C, Leemans J, Montagu M V, Schell J . Ti plasmid vector for the introduction of DNA into plant cells without alteration of their normal regeneration capacity
EMBO J, 1983,2(12):21432150.
URLPMID:16453482 [本文引用: 1]
A Ti plasmid mutant was constructed in which all the on-cogenic functions of the T-DNA have been deleted and replaced by pBR322. This Ti plasmid, pGV3850, still mediates efficient transfer and stabilization of its truncated T-DNA into infected plant cells. Moreover, integration and expression of this minimal T-DNA in plant cells does not interfere with normal plant cell differentiation. A DNA fragment cloned in a pBR vector can be inserted in the pGV3850 T-region upon a single recombination event through the pBR322 region of pGV3850 producing a co-integrate useful for the transformation of plant cells. Based upon these properties, pGV3850 is proposed as an extremely versatile vector for the introduction of any DNA of interest into plant cells.

[45] Christou P, Swain WF, Yang N, Mccabe DE . Inheritance and expression of foreign genes in transgenic soybean plants
Proc Natl Acad Sci USA, 1989,86(11):7500-7504.
URLPMID:16594073 [本文引用: 1]
Abstract DNA-coated gold particles were introduced into meristems of immature soybean seeds using electric discharge particle acceleration to produce transgenic fertile soybean plants. The lineages of integrated foreign DNA in two independently transformed plants were followed in the first (R(1)) and second (R(2)) generation of self-pollinated progeny. One plant (4615) was transformed with the Escherichia coli genes for beta-glucuronidase and neomycin phosphotransferase II; the other (3993) was transformed only with the gene for beta-glucuronidase. Segregation ratios for the introduced gene(s) were approximately 3:1 for plant 4615 and 1:1 for plant 3993 in the R(1) generation. DNA analysis showed 100% concordance between presence of the foreign gene sequences and enzyme activity. Moreover, all copies of the foreign genes are inherited as a unit in each plant. Plant 3993 segregated in a 1:1 ratio in the R(2) generation. R(1) plants derived from plant 4615, which expressed both genes, gave either 100% or 3:1 expression of both genes in the R(2) generation, demonstrating recovery of both homozygous and heterozygous R(1) plants. Our results show that foreign DNA introduced into soybean plants using electric discharge particle acceleration can be inherited in a Mendelian manner. Results also demonstrate cotransformation of tandem markers and show that both markers are inherited as closely linked genes in subsequent generations. These results indicate that whole plants can be derived from single transformed cells by a de novo organogenic pathway.

[46] Vasil V, Castillo A M, Fromm M E, Vasil I K . Herbicide resistant fertile transgenic wheat plants obtained by microprojectile bombardment of regenerable embryogenic callus
Nat Biotechnol, 1992,10(6):667-674.
URL [本文引用: 1]
Nature Biotechnology journal featuring biotechnology articles and science research papers of commercial interest in pharmaceutical, medical, and environmental sciences.

[47] An HL, Wei ZM, Huang JQ . Gold particle amount per bombardment of wheat transformation by biolistic method and phenotypic character analysis of transgenic plants and their progenies
Acta Phytophy Sin, 2001,27(1):21-27.
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安海龙, 卫志明, 黄健秋 . 基因枪法转化小麦的金粉用量及转基因植株表型特征分析
植物生理学报, 2001,27(1):21-27.
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[48] Cheng M, Fry JE, Pang S, Zhou H, Hironaka CM, Duncan DR, Conner TW, Wan Y . Genetic transformation of wheat mediated byAgrobacterrium tumefaciens
Plant Physiol, 1997,115(3):971-980.
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[49] Ma BT, Li P, Zhu Z, Zhou KD . Obtaining transgenic elite Indica restorer line and study on genetic stability of transgenes
Chin J Rice Sci, 2002,16(3):211-215.
URLMagsci [本文引用: 1]
用基因枪法将雪花莲外源凝集素基因（gna）转移到优良籼型杂交稻恢复系蜀恢527中，通过PCR、PCR Southern blotting和Southern blotting等分子方法检测证明，外源基因已稳定遗传到转基因第三代（T2）。转基因第一代植株（T0）在株高和结实率上与相应的组培、种子实生苗植株相比，发生明显的不可遗传的变异。随着繁殖代数的增加，转基因植株恢复到与对照植株一致。还讨论了DNA微量提取法在转基因后代筛选中的运用。
马炳田, 李平, 朱祯, 周开达 . 转抗虫基因优良籼型恢复系的获得及其外源基因的遗传稳定性研究
中国水稻科学, 2002,16(3):211-215.
URLMagsci [本文引用: 1]
用基因枪法将雪花莲外源凝集素基因（gna）转移到优良籼型杂交稻恢复系蜀恢527中，通过PCR、PCR Southern blotting和Southern blotting等分子方法检测证明，外源基因已稳定遗传到转基因第三代（T2）。转基因第一代植株（T0）在株高和结实率上与相应的组培、种子实生苗植株相比，发生明显的不可遗传的变异。随着繁殖代数的增加，转基因植株恢复到与对照植株一致。还讨论了DNA微量提取法在转基因后代筛选中的运用。

[50] Zhao TJ, Zhao SY, Chen HM, Zhao QZ, Hu ZM, Hou BK, Xia GM . Transgenic wheat progeny resistant to powdery mildew generated by
Agrobacterium inoculum to the basal portion of wheat seedling. Plant Cell Rep, 2006,25(11):1199-1204.
[本文引用: 1]

[51] Keshamma E, Rohini S, Rao KS, Madhusudhan B, Kumar MU . Tissue culture-independent in planta transformation strategy: an Agrobacterium tumefaciens-mediated gene transfer method to overcome recalcitrance in cotton ( Gossypium hirsutum L.)
J Cott Sci, 2008,12(3):264-272.
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[52] Ghedira R, De Buck S, Nolf J, Depicker A . The efficiency of Arabidopsis thaliana floral dip transformation is determined not only by the Agrobacterium strain used but also by the physiology and the ecotype of the dipped plant
Mol Plant Microbe Int, 2013,26(7):823-832.
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[53] Das P, Joshi NC . Minor modifications in obtainable Arabidopsis floral dip method enhances transformation efficiency and production of homozygous transgenic lines harboring a single copy of transgene
Adv Biosci Biotechnol, 2011,2(2):59-67.
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[54] Zhang H, Zhang JS, Wei PL, Zhang BT, Gou F, Feng ZY, Mao YF, Yang L, Zhang H, Xu NF, Zhu JK . The CRISPR/Cas9 system produces specific and homozygous targeted gene editing in rice in one generation
Plant Biotechnol J, 2014,12(6):797-807.
URL [本文引用: 1]

[55] Wang YP, Cheng X, Shen QW, Zhang Y, Liu JX, Gao CX, Qiu JL . Simultaneous editing of three homoeoalleles in hexaploid bread wheat confers heritable resistance to powdery mildew
Nat Biotechnol, 2014,32(9):947-952.
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[56] Merker A . Identification of aneuploids in a line of hexaploid Triticale
Hereditas, 1973, 74(1):1-6.
URL [本文引用: 1]
In the progeny of euploid plants in a line of hexaploid Triticale 39 monosomics and 15 trisomics were cytologically identified. No significant deviation from a random distribution between the genomes of the two united species, i.e. one third rye chromosomes and two thirds wheat chromosomes was found.

[57] Bento M, Pereira HS, Rocheta M, Gustafson P, Viegas W, Viegas W, Silva M . Polyploidization as a retraction force in plant genome evolution: sequence rearrangements in Triticale
PLoS One, 2008,3(1):e1402.
URLPMID:2151762 [本文引用: 1]
Abstract BACKGROUND: Polyploidization is a major evolutionary process in plants where hybridization and chromosome doubling induce enormous genomic stress and can generate genetic and epigenetic modifications. However, proper evaluation of DNA sequence restructuring events and the precise characterization of sequences involved are still sparse. METHODOLOGY/PRINCIPAL FINDINGS: Inter Retrotransposons Amplified Polymorphism (IRAP), Retrotransposons Microsatellite Amplified Polymorphism (REMAP) and Inter Simple Sequence Repeat (ISSR) largely confirmed the absence of any intraspecific variation in wheat, rye and triticale. The comparative analysis of banding profiles between wheat and rye inbred lines revealed 34% of monomorphic (common to both parental species) bands for the ten different primer combinations used. The analysis of triticale plants uncovered nearly 51% of rearranged bands in the polyploid, being the majority of these modifications, due to the loss of rye bands (83%). Sequence analysis of rye fragments absent in triticale revealed for instance homology with hydroxyproline-rich glycoproteins (HRGP), a protein that belongs to a major family of inducible defence response proteins. Conversely, a wheat-specific band absent in triticale comprises a nested structure of copia-like retrotransposons elements, namely Claudia and Barbara. Sequencing of a polyploid-specific band (absent in both parents) revealed a microsatellite related sequence. Cytological studies using Fluorescent In Situ Hybridization (FISH) with REMAP products revealed a widespread distribution of retrotransposon and/or microsatellite flanking sequences on rye chromosomes, with a preferential accumulation in heterochromatic sub-telomeric domains. CONCLUSIONS/SIGNIFICANCE: Here, we used PCR-based molecular marker techniques involving retrotransposons and microsatellites to uncover polyploidization induced genetic restructuring in triticale. Sequence analysis of rearranged genomic fragments either from rye or wheat origin showed these to be retrotransposon-related as well as coding sequences. Further FISH analysis revealed possible chromosome hotspots for sequence rearrangements. The role of chromatin condensation on the origin of genomic rearrangements mediated by polyploidization in triticale is also discussed.