小麦温敏核雄性不育系BNS育性转换关键调控基因发掘

Heterosis utilization is one of the most important methods to increase crop yield and improve its quality. BNS is a thermo-sensitive genic male sterile wheat line bred by Professor Ru zhen-gang from Henan Institute of Science and Technology. In the suitable growth areas, BNS could show absolute male sterile or complete normal fertility if the temperature was suitable at its thermo-sensitive stage, and that the fertility transition pattern was steady in different years. The male fertility of BNS can also be completely restored by some normal cultivars. Additionally, the male sterile degree and the male fertile one have met the requirements for large-scale producing hybrid and self-production. So, BNS may be a breakthrough in the research of two-line hybrid wheat in Huang-huai wheat growth area. But till now, the molecular mechanism of the fertility alteration of BNS has not yet been systematically studied. In this study, using RNA-seq method together with group analysis, we will try to discover genes crucial for regulating the fertility alteration of BNS through analysis the differences of gene expression of BNS in thermo-sensitive phages under sterile and fertile conditions, which will highlight the understanding of molecular mechanism of the fertility alteration of BNS and development of functional markers for thermo-sensitive genic male sterile gene.

杂种优势利用是提高作物产量改善作物品质的重要途径。BNS是河南科技学院茹振钢教授培育的低温敏感型核雄性不育系，在广大适宜区域内表现"不育彻底、转换彻底、恢复彻底、育性转换稳定"等显著特征，其制种不育度和自繁可育度均达到生产上规模化杂交制种与繁种要求，是黄淮麦区二系杂交小麦的新突破，但其育性转换的分子机制尚缺乏系统研究。本项目的研究内容：以BNS幼穗为材料，利用转录组测序技术结合遗传群体分析，研究低温敏感时期BNS在可育与不育条件下的基因表达差异，发掘其育性转换的关键调控基因。本项目首次从分子水平上研究BNS在可育与不育条件下的基因表达差异，进而发掘其育性转换的关键调控基因，这将为阐明BNS育性转换的分子机制以及开发功能性的分子标记奠定基础。

BNS型不育系是低温敏感型核雄性不育系，是黄淮麦区二系杂交小麦的新突破，近年来受到广泛关注，但其育性转换的分子机制尚缺乏系统研究。本项目以本课题组新转育的BNS型不育系366S为研究对象，利用RNA-seq技术分析了366S在不育与可育条件下的基因表达差异。结果表明：花粉母细胞期，差异表达基因558个；四分体期，差异表达基因484个；单核期，差异表达基因2432个；二核期，差异表达基因2581个。差异基因GO显著性富集结果表明：366S对低温响应最强烈的时期为四分体期，此时期差异基因中有GO分类的基因381个，其中response to cold的差异基因86个，不育条件下上调表达39个，下调表达47个。单核期，不育和可育条件下主要表现细胞组分差异，说明此时期已进入花粉败育效应阶段。因此推测四分体期是366S育性转换调控的关键时期。Pathway显著性富集结果表明：366S花粉败育过程可能涉及内源乙烯信号途径，不育条件下脂肪酸代谢途径异常跟366S花粉败育效应阶段密切相关。从GO分类为response to cold的差异基因中，筛选出在花粉母细胞期和四分体期共同的差异基因26个，在这两个时期均上调的基因15个，均下调的基因11个。其中HSP70和CCCH型锌指蛋白在这两个时期的下调表达，可能跟366S的育性转换密切相关，后续将进一步深入研究它们在366S育性转换中的功能与作用机制。用Ta.3064.1.S1_x_at作内参，随机挑选5个unigene进行Q-RT-PCR分析，4个时期的表达变化模式与RNA-seq结果一致，说明RNA-seq数据是可信的。