小麦品系陕农69抗条锈病基因yrSN69的精细定位

Stripe rust, caused by Puccinia striiformis Westend. f. sp. tritici Erikss.(Pst), is one of the most destructive diseases of common wheat (Triticum aestivum L.) in China. Developing resistant wheat cultivars is the most economical and effective method to control the disease. The Chinese wheat line Shaannong 69 exhibits moderately resistant to CYR32 at seedling stage in greenhouse and a high level of resistance to stripe rust in the field, thus it is a valuable germplasm for resistance to stripe rust. Genetic and SSR analysis indicated that Shaanong 69 contained a single recessive resistance gene on chromosome 6BL, tentatively designated yrSN69. The first aim of this project is to finely map stripe rust resistance gene yrSN69 using comparative genomic analyses and wheat genome sequence information, as well as RGAP and EST approach,to find 5 to 6 cosegregating or closely linked molecular markers.Secondly, the parents, and the resistant and susceptible bulks derived from the cross Mingxian 169/Shaannong 69 will be analyzed using Wheat 90K iSelect assay. Based on the original DNA sequences of polymorphic SNP markers, the corresponding STS markers will be developed to test the bulks and entire F2 population. This will identify 5 to 6 molecular markers cosegregating or closely linked to resistance gene yrSN69 with genetic distances of less than 1.0 cM. The molecular markers developed in this study will provide essential information for cloning of the resistance gene and facilitate wheat molecular breeding.

小麦条锈病是我国小麦的主要病害之一，选育抗病品种是防治条锈病最经济、有效的措施。小麦品系陕农69多年来对条锈病一直表现良好的抗性，对我国当前流行小种CYR32苗期表现中抗，田间成株期表现高抗，是一个很有价值的条锈病抗源。遗传分析和SSR标记分析表明，陕农69携带一个位于6BL染色体的隐性抗条锈病基因，暂命名为yrSN69。 本项目一方面将利用RGAP、EST标记及比较基因组策略和小麦基因组序列信息，对条锈病抗性基因yrSN69进行精细定位，发掘其共分离或者紧密连锁的分子标记5-6个；另一方面利用小麦90K SNP芯片检测群体的双亲和抗感池，发现抗感池间多态性的SNP标记，并将多态性的SNP标记转化为STS标记，最终找到与抗病基因共分离或者连锁距离在1.0 cM以内的分子标记5-6个。这些分子标记的发掘将为抗病基因yrSN69的克隆和分子育种奠定基础。

摘要：本项目按计划进行，发表学术论文2篇，其中SCI论文1篇。培养硕士研究生2名，其中1名已顺利毕业。主要研究内容及结果汇总如下：由条锈菌（Puccinia strliformis f. sp. tritici）引起的小麦条锈病是世界范围内的重要真菌病害，严重威胁小麦生产。1）本研究以小麦品系陕农69为材料，对抗条锈病基因yrSN69进行精细定位，将该基因锁定在6BL染色体上的0.46Mb的区间中；2）利用BSA+90K SNP芯片策略，得到了2个与yrSN69基因紧密连锁的SNP位点，IWA3224和IWB65615；3）根据目标scaffold序列的基因注释，开发了2个与yrSN69基因紧密连锁的基因特异性分子标记，暂命名为TaRGA1 和TaLecRK，它们与yrSN69间的距离分别为1.81和1.82 cM；4）利用BSA+660K SNP芯片策略，筛选到了37个位于目标scaffold中的多态性SNP位点，目前正利用KASP技术对它们进行验证，期望得到更多的连锁更紧密的SNP位点。本研究中得到的与yrSN69基因紧密连锁的分子标记将为该基因的克隆以及分子标记辅助育种奠定基础。