小麦农家品种鸟麦广谱抗白粉病新基因Pm2c的精细定位、候选基因分离及标记辅助转育

Niaomai, Chinese wheat landrace, is an elite and broad-spectrum powdery mildew resistance resource with a dominant powdery mildew resistance gene. The previous data showed that the gene was a new resistance Pm2 allele formally designated Pm2c. Marker analysis indicated that Pm2c was located on the physical deletion bin 5DS1-0.63 and 0.6 cM genetic region flanked by maker loci Xcfd81 and Xbwm21. To fine map, isolate and utilize Pm2c gene, this program plans to develop polymorphic molecular markers, establish super-saturated gentic map and fine map this resistance gene by using the methods of Aegilop genome sequences, 660K SNP gene chip scanning, SLAF-Seq (Specific-Locus Amplified Fragment Sequencing) and BSR-Seq (Bulked Segreganted RNA Sequencing); confirm the corresponding BAC physical map and sequence region of Aegilops genome with Pm2c and construct physical map of Pm2c gene locus and isolate the target candidate gene combining BAC library screening and chromosome walking; with the aid of marker-assisted selection, transfer the Pm2c gene into wheat released cultivars and develop near isogenic lines in different genetic backgrounds, new elite resistant wheat lines and diagnostic molecular markers in wheat resistant breeding. The study of this program will facilitate the map-based cloning of Pm2c gene and molecular design breeding.

我国小麦农家品种鸟麦是一个广谱、优异的白粉病抗源，携带单个显性抗白粉病基因，前期工作证明该基因是Pm2位点一个新的等位基因，被正式命名为Pm2c；标记分析将其定位在小麦5DS1-0.63的物理区域和两侧标记位点Xcfd81和Xbwm21之间0.6 cM的遗传区间。为了精细定位Pm2c并分离其候选基因以及利用该基因，本项目拟用粗山羊草基因组序列、660K SNP基因芯片扫描、SLAF-Seq和BSR-Seq等方法开发多态性分子标记，构建Pm2c的超饱和遗传图谱，精细定位Pm2c；确定Pm2c对应粗山羊草基因组的BAC物理图谱和序列区间，结合BAC文库筛选和进行染色体步移，构建覆盖基因位点的物理图谱，确定目标候选基因，进行分离；结合标记辅助选择，将Pm2c导入到小麦主栽品种中，创制不同遗传背景的近等基因系和优异的抗白粉病小麦新品系。本研究工作的开展将为Pm2c的图位克隆和分子设计育种奠定基础。

白粉病是影响小麦产量与品质的重要病害。农家品种鸟麦是一个广谱的、优异的白粉病抗源。遗传分析、分子标记定位、抗谱分析以及等位性测试表明，该基因是Pm2位点一个新的等位基因，被国际小麦基因命名委员会正式定名为Pm2c。通过小麦BSR-Seq测序技术以及构建遗传分离大群体，对Pm2位点抗病基因进行了精细定位，并构建了饱和遗传连锁图谱，对其候选基因进行了分离、克隆，并开发了育种可用的、高通量检测的分子标记，通过分子标记辅助选择创制了以主栽品种为背景、高抗白粉病、综合农艺性状优良的Pm2c的导入系，创制的这些新种质可应用于小麦抗白粉病的分子育种。发表标注本项目资助的SCI论文3篇，申报发明专利1项，培养研究生4名。