小麦抗秆锈病基因Sr22的SSR新标记

 【目的】利用微卫星技术筛选与Sr22紧密连锁的标记,从而应用于分子辅助育种选择与抗性种质基因检测分析。【方法】以抗秆锈病单基因系SWSr22与感病品种McN701为亲本杂交获得F1,单粒F1种子自交获得F2群体,选用中国流行小麦秆锈菌小种21C3CTH接种鉴定,进行遗传分析;利用分离群体集群分析法(BSA)对位于7A染色体的73对SSR引物进行多态性筛选,具有多态性的引物再通过SWSr22×McN701的F2抗感群体与F2﹕3家系的植株进行验证。【结果】该单基因系SWSr22对21C3CTH的抗性属于单位点显性遗传,并筛选到2对在亲本及F2抗感群体间揭示多态性的SSR引物Xwmc790和Xwmc633。通过对F2分离群体的分析表明,这2个标记与抗病基因Sr22紧密连锁,呈共显性,分布于该基因的同一侧,位于远着丝点处,与Sr22的遗传距离分别为2.8 cM和10.8 cM。【结论】这2个标记与抗病基因Sr22紧密连锁,经验证可用于小麦抗秆锈病分子标记辅助育种。

New SSR Markers for Stem Rust Resistance Gene Sr22 in Wheat

【Objective】 The microsatellite markers closely linked to Sr22 were screened to be used in marker-assisted selection for breeding and gene detection (diagnose) for resistant germplasm and varieties. 【Method】 A population of F2 plants was generated from one F1 plant derived from a cross between susceptible wheat cultivar McN701 and wheat monogenic line SWSr22, and seedlings of parents and F2 plants were inoculated for genetic analysis. In addition, parental DNA and bulked segregant analysis (BSA) were used to screen for polymorphism with 73 SSR markers that covered the chromosome 7A of wheat. The markers showing DNA polymorphism were validated by F2 population and F2:3 family of SWSr22×McN701. 【Result】 The resistance to 21C3CTH must be the gene contained in monogenic line SWSr22 and was controlled by a single dominance. Two co-dominant markers Xwmc790 and Xwmc633 were identified and mapped on the distant side of centromere, with distances of 2.8 cM and 10.8 cM, respectively. 【Conclusion】 The two markers were tightly linked with Sr22 and could be used in marker-assisted selection of Sr22 for breeding.