黏类小麦育性相关基因SSH文库的构建

为了深入研究黏类小麦雄性不育的分子遗传机制, 利用抑制差减杂交技术构建了黏类小麦育性相关基因的cDNA文库。文库质量检测表明, 差减杂交效率较高, 质量较好。在不育和可育cDNA文库中随机挑选120个阳性克隆进行测序, 获得100余条高质量的表达序列标签(EST)。对序列进行BLAST比对及功能注释, 比较了不育和可育cDNA文库的基因表达谱, 发现在可育cDNA文库中参与能量代谢的基因出现频率较高, 在不育cDNA文库中检测到了与花发育调控相关的MADS-box转录因子、细胞凋亡相关的泛素结合酶及阻遏淀粉合成的腺苷二磷酸葡萄糖磷酸化酶等相关基因。这些基因很可能与育性相关。     

一个与小麦雄性不育育性转换相关的MADS-box转录因子基因

为了揭示YS型小麦温敏雄性不育育性转换的基础, 构建了该类型不育系A3017的不育和可育幼穗正、反杂交的两个SSH-cDNA文库。经文库比较, 在不育文库中筛选出一个与MADS-box基因同源的EST序列(GenBank登录号: 36925702)。以该EST序列的同源性比对和拼接结果为依据, 设计引物对该基因在可育和不育幼穗中的表达进行了RT-PCR分析, 结果表明, 该基因在不育幼穗中表达量较高, 可育幼穗中表达量很低。对不育幼穗中扩增出的cDNA片段进行克隆测序, 获得了666 bp的cDNA序列。序列分析表明, 该片段编码160个氨基酸, 具有MADS-box转录因子的典型结构域K-box, 被定名为TaMS-MADSbox, 与一个小麦MADS box转录因子基因WAG的氨基酸序列的相似性为94%。进一步以3种不同类型的小麦雄性不育系和保持系的幼穗cDNA为材料, 利用半定量RT-PCR对该基因的表达模式分析发现也存在类似差异, 该基因在不育系幼穗中表达量较高, 而保持系幼穗中表达量较低。以上分析表明, 该MADS-box转录因子基因的表达与小麦雄性不育系的育性转化相关, 表达量高时表现雄性不育, 表达量低时表现雄性可育。     

小麦雄性不育育性转换相关基因TaG3BP的克隆与表达分析

为揭示YS型小麦温敏雄性不育的育性转换基础,以该类型不育系A3017不育幼穗和可育幼穗为材料构建正、反杂交SSH-cDNA文库,从可育文库中筛选出一个与G3BP(Ras-GTPase activating protein SH3 domain-binding protein)基因同源的EST序列(GenBank登录号为DY543200)。以该EST序列的同源性比对和拼接结果为依据设计引物,在可育幼穗中扩增出一条1230bp的cDNA序列。该片段含有与G3BP相似的由409个氨基酸组成的结构域,与水稻G3BP的氨基酸序列同源性为79%,被命名为TaG3BP(GenBank登录号为GU475149)。利用Real-time PCR检测TaG3BP基因在YS型小麦温敏雄性不育系花药发育各时期中的表达模式,发现该基因在育性转换的关键时期上调表达,且可育条件下的表达量高于同时期不育条件下的表达量。进一步对TaG3BP在3种不同类型的小麦K型雄性不育材料的不育系及其保持系的幼穗中的表达模式进行半定量RT-PCR分析,结果该基因在保持系幼穗中表达量较高,在不育系中表达量较低。表明该基因可能在其育性转换中具有重要作用。     

GAPDH基因表达与小麦生理型雄性不育花药败育的关系

为分析三磷酸-甘油醛脱氢酶(GAPDH)基因与小麦(Triticum aestivum)生理型雄性不育花药败育的关系,本研究以新型小麦化学杀雄剂SQ-1作为诱导剂,普通小麦西农1376为材料,构建了西农1376不育和可育等生理系;采用半定量逆转录聚合酶链式反应(RT-PCR)技术分析了不育和可育等生理系不同发育时期花药中GAPDH基因的表达模式.结果表明,该基因在正常小麦花粉发育的单核期、二核期和三核期,表达丰度比较一致,没有明显变化,但在化学杀雄剂SQ-1诱导的生理型雄性不育花药中,不同发育期表达量存在显著差异,单核期表达最弱,二核期最高.与同期正常花药相比,GAPDH基因在生理型雄性不育花药三个发育期均呈下调表达,其中在大量花粉粒败育的单核期,表达量下调最显著,其次为三核期和二核期,证明化学杀雄剂SQ-1对GAPDH基因的表达具有明显抑制作用.因此,化学杀雄剂SQ-1诱导小麦生理型雄性不育形成过程中,可能与GAPDH基因表达减少导致细胞中能量供给不足有一定关系.     

湖北光周期敏感核不育水稻农垦58s花药中的某些生化代谢特点

湖北光周期敏感核不育水稻农垦58s单核早期的不育花药的线粒体呼吸速率和LOX活性分别较可育株低11.9％和5％,而单核晚期相应较可育株低18.4％和17.3％。花药发育从单核期至三核期,可育花药的AsA和GSH含量增高,而不育花药仅分别相当于可育株的35—55％和22—32％,并有脂质氢氧化物积累。随着花药发育,可育花药的AsA-POD,GR和6-GPDH活性逐有增高,至三核期达到最高。而不育花药,随花粉败育,在单核早期至三核期,AsA-POD,GR和6-GPDH活性逐渐降低,至三核期,其活性分别为可育株的26％,22％和19％,不育花药的ME和MDH活性亦较可育株低。IDH活性在单核晚期为可育株的47—80％。细胞还原势低是不育花药特征之一。低的还原势可能导致活性氧代谢失调和花药不育。     

小麦K-型细胞质雄性不育系COI1基因的克隆与表达分析

COI1(coronatine-insensitive 1)基因是茉莉素信号传导中起关键作用的基因,与植物的抗病性、花粉育性密切相关。为探讨COI1与小麦K型细胞质雄性不育性之间的关系,本研究从小麦K型细胞质雄性不育系豫麦3号中同源克隆得到COI1基因的三个拷贝。该基因大小为2.8 kb,开放阅读框为1 761 bp,编码586个氨基酸残基的蛋白,含有COI1蛋白典型的F-box和LRR保守结构域。进化分析结果表明COI1基因的三个拷贝分别与来自小麦祖先种乌拉尔图小麦、拟斯卑尔脱山羊草和粗山羊草、大麦以及短柄草的COI1亲缘关系较近,而与拟南芥、大豆、黄瓜等的COI1亲缘关系较远。利用中国春缺体四体系统进行染色体定位分析,发现它们分别定位于小麦4A、4B、4D染色体上。对COI1基因在小麦品种中国春的根、茎、叶和幼穗中的表达模式分析发现三个拷贝呈组成型表达,但幼穗中Ta COI1A的表达量明显高于Ta COI1B和Ta COI1D。在不育系、保持系和F1代不同发育时期的花药中,COI1基因的三个拷贝在不育系单核期花药的表达量明显高于保持系,在二核期至三核期(不育系花粉败育的关键时期),Ta COI1B和Ta COI1D在不育系和保持系中的表达趋势一致,而Ta COI1A在不育系中的表达呈上调趋势,在保持系和F1代中的表达呈下调趋势,说明Ta COI1A基因在不育系和可育系(保持系和F1代)花药中的表达有明显差异,可能跟不育系的花粉败育有关。     

抑制消减杂交法研究复等位基因遗传的

AB01是本课题组培育的复等位基因遗传的核雄性不育大白菜甲型“两用系”,目前已建立了一套该材料的应用技术体系,但其不育分子机制尚不明确。本研究以AB01的不育株和可育株为材料,利用抑制差减杂交技术构建了正反抑制差减cDNA文库,并通过测序及生物信息学手段寻找育性相关基因,以此来推断该材料的不育分子机制。研究中共找到27个差异表达基因,其中25个基因在NCBI数据库中均有同源序列,这些基因中7个与花发育相关,5个与脂类代谢相关,3个与活性氧及能量代谢相关,3个与光合作用及叶绿体合成相关,其余7个为功能未知基因。由此推测复等位基因遗传的核雄性不育大白菜不育的发生与脂类、能量代谢及光合作用有关。     

ATP合成相关基因在小麦BNS不育系育性转换中的差异表达

为了探讨ATP合酶α亚基和腺嘌呤磷酸核糖基转移酶(APRT)与温敏雄性不育系BNS育性的联系,利用荧光实时定量PCR方法,在花药发育的4个重要时期(四分体期、单核期、二核期和三核期),定量检测ATP合酶α亚基和APRT相关基因在不育及可育条件下花药中的mRNA表达水平。不育条件下,ATP合酶α亚基基因从四分体到二核期表达量持续下降,与可育株相比在单核期表达量显著下降;APRT1在4个时期的表达量低于其在相应可育条件下的表达量,而APRT2基因在BNS不育和可育条件下维持较低的表达水平。APRT相关基因表达量在三核期均有较显著提高,且可育条件下比不育条件下提高更明显。因此认为,ATP合酶α亚基基因与BNS育性转换密切正相关,APRT基因在三核期转录水平的变化与BNS育性转换有一定关系。     

棉花473A育性表达中花药脱落酸和玉米素＋玉米素核苷含量变化

以棉花核型雄性不育姊妹系４７３Ａ为材料，采用酶联免疫检测（ＥＬＩＳＡ）技术分析４７３Ａ不育株和可育株花药发育过程中花药脱落酸（ＡＢＡ）和玉光大＋玉米素核苷（Ｚ＋ＺＲ）合量变化。在花药发育各个时期，不育株花药ＡＢＡ含量都高于可育株，Ｚ＋ＺＲ含量低于可育株。尤其在减数分裂期，不育株花药ＡＢＡ含量是可育株的７３．１倍，Ｚ＋ＺＲ含量仅为可育株的４２．６％。因此，不育株花药中ＡＢＡ含量与Ｚ＋ＺＲ含量的比值严重失调。表明，４７３Ａ不育株花药败育的关键时期在减数分裂期，花药ＡＢＡ含量和Ｚ＋ＺＲ含量与雄性育性的表达密切相关。     

黏类小麦细胞质雄性不育线粒体atp6基因转录本编辑位点

以黏类小麦细胞质雄性不育系ms(Kots)-90-110(A)及其近等可育基因系BC₅F₂为材料,采用克隆测序与PCR产物直接测序方法,对黏类小麦线粒体atp6基因在花药发育各阶段的RNA编辑进行了分析。结果表明,小麦atp6基因保守区DNA序列在供试材料不育系及其近等可育基因系中完全一致,且与普通小麦和提莫菲维小麦atp6基因序列同源性为99%。两种方法测序分析atp6基因转录本保守区RNA编辑的结果规律相似。atp6基因共有15个编辑位点,其中13个发生在密码子的第一和第二位点上,这些位点的编辑都使氨基酸种类发生了变化;有2个发生在密码子的第三位点上,不引起氨基酸种类的变化;其中第6和第7位点是共转录的。随着花药发育时期的推移,各位点的编辑频率逐渐增高。不育系与其近等可育基因系相比,在引入核恢复基因后,各位点的编辑频率明显提高。编辑不充分的转录产物可能会影响线粒体功能的正常发挥,表明黏类小麦细胞质雄性不育与线粒体atp6基因转录本保守区的编辑有一定的相关性。     

白菜型冬油菜温敏不育系PK3-12S育性转换的差异蛋白质组学分析

为揭示温敏不育系PK3-12S育性转换机制,本研究以白菜型冬油菜温敏不育系PK3-12花药为材料,采用2-DE和LC-MS/MS质谱鉴定等差异蛋白组学方法,分离鉴定了PK3-12在不育/可育条件下花药差异表达蛋白质,并对差异表达蛋白进行了生物信息学分析;进而采用RT-PCR检测了PK3-12在不育/可育条件下花蕾发育进程中差异蛋白编码基因表达量变化。结果表明,高温不育条件下, PK3-12花药形态瘪小,药室有少量败育花粉,育性转换受1对隐性基因控制,表达变化量在2倍以上差异蛋白质点31个,其中增量表达蛋白质点6个,减量表达蛋白质点11个,表达完全抑制蛋白点12个,不育花药特异表达蛋白点2个。质谱鉴定出15个差异蛋白质,参与信号转导通路、二羧基乙醛酸代谢、糖酵解代谢、次生合成代谢、氨基酸生物合成、分支酸生物合成、碳代谢途径等细胞过程。Rubisco亚基连接蛋白编码基因BrrbcL开放读码框(open reading frame, ORF)长度为1095 bp,编码364个氨基酸;与可育花蕾相比,发育进程中不育花蕾BrrbcL基因、膜联蛋白基因(ANN)、BetVI过敏原家族基因(BetVI)表达明显下调,表明上述基因可能参与了温敏不育系PK3-12S育性的转换。     

棉花核不育系豫98-8A育性遗传分析

为了阐明1999年从转基因后代遗传群体中发现的1株雄性不育植株不育基因的遗传规律及其与现有不育基因的等位性,采用表型观察测量,以及经典的自交和测交手段,研究了该不育材料败育性状的遗传规律。花器官形态特征调查表明：不育株花柱长和花柱外露长度均明显高于同质系的正常可育株,而每朵花的子房直径及花药数量没有明显差异。遗传分析表明：杂合体可育株自交,后代不育株与可育株呈3:1分离,不育株与杂合姊妹可育株测交,不育株与可育株呈1:1分离,表明该核不育材料受隐性单位点控制;与阆A(msc1)、洞A(msc3)等育性位点杂合可育株分别杂交,其F1代单株育性均得到恢复。由其F1代产生的F1:2家系中均出现不育株与可育株呈1:3和7:9两个育性分离群体,表明该材料败育基因为不同于阆A、洞A的不育基因位点。     

Cytological screening of rice TGMS lines

An investigation was undertaken to develop new stable thermo‐sensitive genic male sterility (TGMS) rice lines in intermated progenies (IMPs) of TGMS lines by using an anther clearing technique. The results indicate that both pre‐ and post‐meiotic genetic systems operate during anther development for the expression of sterility in TGMS lines. In all the TGMS lines, sterile anthers were small with empty pollen grains of irregular shape, except for TS 16, which showed pollen‐free anthers. This indicates that the sensitive stage of TS 16 is around stage IV (stamen and pistil primordia) of panicle development. Distinct differences were observed between sterile and fertile phases with respect to anther size, shape and colour of the pollen grains in TS 18 and TS 29. The pollen grains at the sterile phase were small and irregular in shape while in the fertile phase they were plump and larger with a yellow colour, establishing that the occurrence of sterility in TS 18 and TS 29 is post‐meiotic. Three distinct classes of pollen fertility percentage viz. <20%, 50‐70% and >90% were observed in IMPs. Anther clearing in IMPs showed distinct developmental patterns of pollen production with respect to distinct classes of pollen fertility. Less than 20% pollen fertility was observed in hybrids such as TS 15 × TS 16, TS 15 × Co 47, TS 18 × TS 16 and TS 18 × Co 47 which hold promise for developing new TGMS lines with a good plant type and acceptable quality.     

Characterization of a male sterile mutant from progeny of a transgenic plant containing a leaf senescence-inhibition gene in wheat

A male sterile plant of wheat (Triticum aestivum L.) segregated from progenies of a transgenic family containing the leaf senescence-inhibition gene P _SAG12 -IPT in the genetic background of ??Xinong 1376??, a well adapted winter wheat cultivar. The male sterile plant (named TR1376A) showed no phenotypic changes, except for florets and male organs, compared to its male fertile sibling plants (named TR1376B). The glumes and florets of male sterile TR1376A plants widely opened whereas those of the fertile counterpart TR1376B were closed or opened only briefly at flowing. Anthers of TR1376A were slender and indehiscent, and failed to release pollen. Compared to TR1376B, TR1376A anthers contained greatly reduced amounts of pollen, which was inviable or weakly viable. Ultra-structure studies indicated that cells in the endothecium and middle layers of the anther wall were dissolved or poorly developed in the sterile anthers of TR1376A. Molecular studies showed that the male sterility of TR1376A was caused by a sequence deletion or mutation that occurred in the promoter region of the transgene. F₁ hybrids of TR1376A and TR1376B gave 1:1 segregation of male fertility to sterility, indicating that the male sterility of TR1376A was heritable and controlled by a single dominant gene (named Ms1376). To date, only a few dominant nuclear male sterility genes have been characterized and one of them (Ms2) has been successfully used to improve wheat cultivars through recurrent breeding strategies. The discovery of the Ms1376 gene provides another dominant male sterile source for establishing recurrent breeding systems in wheat.     

Genetic and cytological analysis of a new spontaneous male sterility in radish (<Emphasis Type="Italic">Raphanus sativus</Emphasis> L.)

A male sterile plant appeared in the radish breeding program at the Hubei Academy of Agricultural Sciences, Hubei, China. In its progeny, a two-type (half of plants male sterile, the other half male fertile) line 01GAB was established. An F₂ population of 260 plants from a cross of male-sterile 01GAB and a male fertile line 9802H segregated for male fertility in a 3:1 ratio indicating that fertility was restored by a single dominant gene, here designated RsMs. A PCR-based DNA marker specific to the male fertility Rfob gene in 9802H was absent in 01GAB. Linkage analysis placed the RsMs locus 10.7 cM away from the Rfo locus. In an F₂ population of hybrids between 01GAB and male fertile 9802B, a co-dominant DNA marker for the RSultr3.2A (a radish sulfate transporter gene) locus was linked to the RsMs locus at 1.5 cM suggesting that fertility restoration in 01GAB was located in the region with known male sterility restorers in radish. However, no maintainer for the 01GAB source of male sterility has been identified so far. Cytological observations have shown that the abnormalities in male sterile anthers first appeared in tapetum at the tetrad stage, followed by a hypertrophy of the tapetal cells at the vacuolate microspore period. These results suggest that male sterility in 01GAB is likely to be genetic in nature, or it may represent a new type of the cytoplasmic male sterility.     

大豆质核互作雄性不育系W 931 A及其保持系不同器官的可溶性蛋白的电泳分析

目的:对大豆质核互作雄性不育系W931 A及其同型保持系W931 B不同器官的蛋白质组进行比较性研究,获得差异蛋白质组的重要信息.方法:采用SDS-PAGE方法.结果:发现不育系W931 A与其保持系W931 B种子和苗期叶片的蛋白质SDS-PAGE电泳图谱基本没有差异带,二胞花粉期花药SDS-PAGE图谱间有3条差异带.结论:雄性不育基因表达具有时空和器官特异性.与育性有关的蛋白主要在花药中表达.     

New insights into genotypic thermodependency of cytoplasmic male sterility for hybrid barley breeding

The cytoplasmic male sterility (CMS) system msm1 in barley is known to be thermosensitive, sometimes resulting in spontaneous fertility restoration in the absence of the corresponding restorer gene Rfm1. Here, we investigated genotypic differences concerning temperature sensitivity and the plant developmental stage at which elevated temperature induces spontaneous fertility restoration in three CMS mother lines. While one line stayed completely male sterile, a significantly higher fertility was observed in two lines after treatment from growth stage DC 41 until maturation. Microscopic analysis revealed that sterile anthers contained neither intact pollen, nor remains of aborted pollen grains, whereas pollen was visible in anthers of potentially fertile plants. We conclude that the barley CMS system affects anther and pollen development prior to meiosis. Elevated temperature during heading and flowering can lead to a spontaneous fertility restoration by reactivating pollen growth. Nevertheless, genotypic variation exists enabling the selection for stable CMS mother lines and the development of F₁ hybrids with high hybridity. As spontaneous fertility restoration due to environmental effects is difficult to phenotype, further investigations will focus on the development of molecular markers for marker‐assisted selection.