源于中间偃麦草的抗条锈基因YrCH223的遗传分析及SSR定位

CH223是一个衍生于中间偃麦草的多抗性小偃麦种质系,通过感病的小麦品种与八倍体小偃麦TAI7047杂交、回交选育而成。抗性鉴定表明,CH223对我国当前小麦条锈病的流行小种CYR32,CYR33均有良好抗性。利用CH223与感病品种(系)的F2,F2∶3和BC1抗性分离群体进行抗性遗传分析,发现其条锈病抗性来自中间偃麦草,且由1对显性基因控制,暂时命名为YrCH223。用CYR32对来自台长29×CH223的221个F2植株进行接种鉴定,并构建抗、感DNA池。共筛选738对SSR引物,发现5对共显性SSR标记与抗病基因连锁,位置顺序为:Xgwm540-Xbarc1096-YrCH223-Xwmc47-Xwmc310-Xgpw7272,遗传距离分别为21.9,8.0,7.2,12.5,11.3 cM。进一步利用中国春缺体-四体和双端体材料扩增鉴定,将YrCH223定位于小麦4B染色体的长臂上(4BL)。经F2∶3群体验证,5个标记与YrCH223连锁。迄今为止,在4BL上未发现有公开报道的抗小麦条锈病基因。因此,基于抗病基因所在的染色体位置与来源,推断YrCH223是一个新的抗条锈病基因。

Genetic Analysis and SSR Mapping of a Thinopyrum intermedium Derived Stripe Rust Resistance Gene YrCH223

Resistance to Chinese stripe rust races,including CYR32 and CYR33,the most widely virulent and predominant pathotypes in China was introgressed into common wheat(Triticum aestivum L.) from Thinopyrum intermedium.Genetic analysis of the F1,F2,F2∶3 and BC1 populations from a cross of the stripe rust resistant line CH223 with susceptible lines revealed that resistance was controlled by a single dominant gene.The resistance gene was mapped using F2∶3 populations.The gene was linked to five co-dominant genomic SSR markers,Xgwm540,Xbarc1096,Xwmc47,Xwmc310 and Xgpw7272,and flanked by Xbarc1096 and Xwmc47.The most likely order was Xgwm540-Xbarc1096-YrCH223-Xwmc47-Xwmc310-Xgpw7272 at 21.9,8.0,7.2,12.5,11.3 cM,respectively.Using the Chinese spring nulli-tetrasomic and ditelosomic lines,the polymorphic markers and the resistance gene were assigned to chromosome 4BL.As no permanently named stripe rust resistance genes have been assigned to chromosome 4BL,this new resistance gene is temporarily named YrCH223.The gene,together with the identified closely linked markers,could be used in marker-assisted selection for pyramiding stripe rust resistance genes.