红蚰麦中抗白粉病基因的精细定位

Powdery mildew is one of the most serious leaf diseases that influenced wheat production. Introducing new powdery mildew resistance genes into adapted cultivars is the most economic effective and environmentally friend means to curb the disease. Our previous study showed that Hongyoumai carries a recessive powdery mildew resistance gene, pmHYM, located on wheat 7BL. This study planned to saturate the interval involved pmHYM and to precisely map the gene by developing large population between Yangmai158 and Hongyoumai and screening the recombinant lines of pmHYM, by acquiring more STS, SSR, SNP markers linked closely to pmHYM according to comparative genomics analysis, sequence information of SNP chip, wheat genome, and RNA-seq. The study also planned to determine the relationship between pmHYM and Pm5 through allelic test, comparation of the resistance spectrum and haplotye analysis between Hongyoumai and other Pm5 carriers. The results may set a basis for map-based cloning in the genetic study and utilization of the gene in wheat improvement.

白粉病是影响小麦生产最严重的叶部病害之一。向推广品种引入新的抗白粉病基因是控制白粉病发生最有效、最环保的措施。本实验室前期在地方品种红蚰麦中鉴定到一个隐性抗白粉病基因pmHYM，并将该基因定位到小麦7BL染色体上。本研究拟通过构建扬麦158×红蚰麦的大群体和筛选pmHYM重组系，利用STS、SSR、SNP等分子标记，结合比较基因组分析、SNP芯片序列信息、小麦基因组序列信息以及RNA-seq测序信息，获得与pmHYM紧密连锁的标记，饱和pmHYM区段，实现该基因的精细定位；通过等位性测试、抗谱分析、单倍型分析，明确pmHYM与Pm5位点间的关系。本研究将为该基因的图位克隆与育种上的有效利用奠定基础。

来自小麦地方品种红蚰麦的抗白粉病基因pmHYM，对小麦白粉病表现出良好的抗性。该基因之前被定位于小麦7BL染色体上，但是遗传标记密度较低。在本研究中，通过利用中国春小麦基因组序列信息结合90kb SNP 芯片信息，开发了12对标记。开发的标记被用于对红蚰麦与辉县红的大群体中的832个纯和抗病家系的重组体筛选和基因型分析，该基因被精细定位在Xmp1207和Xmp1158之间，分别距离抗病基因0.012 cM和0.053 cM。分子标记分析、染色体定位、抗谱分析和等位性测试表明pmHYM是新的Pm5等位基因。利用中国春缺失系将该基因定位在7BL的0.86-1.00染色体臂中。此外，通过简化测序和RNA-seq测序技术获得了12个抗病基因类似物，可作为pmHYM的候选基因。本研究将为该基因的图位克隆与育种上的有效利用奠定基础。