源于柔软滨麦草抗小麦条锈病基因YrElm的遗传分析与SSR标记

Genetic analysis and SSR markers of wheat stripe rust resistance gene YrElm derived from Elymus mollis(Trin.)Hara

M852-1是由柔软滨麦草和普通小麦7182经杂交和回交培育的易位系。苗期抗病性鉴定结果表明,M852-1对CYR29、CYR31、CYR32、CYR33、Su11-4、Su11-7和V26等7个中国小麦条锈菌主要生理小种或新的致病类型均表现免疫至高抗,是一个较好的抗条锈资源材料。用条锈菌流行小种CYR33对M852-1与铭贤169杂交F1、F2、F3和BC1代进行抗性鉴定与遗传分析,发现M852-1对CYR33的抗条锈性由1对隐性基因控制,暂定名为Yr Elm。以F2代分离群体构建作图群体,利用集群分离分析法,筛选到与Yr Elm连锁的5个SSR标记:Xcfd35、Xgwm161、Xwmc630、Xgwm533和Xcfd34,并将Yr Elm定位于小麦染色体3DS上。Yr Elm两侧最近2个SSR标记Xcfd35与Xgwm161的遗传距离分别为6.5 c M和4.2 c M。抗锈性鉴定、系谱分析以及分子标记检测结果表明,该抗病基因来源于柔软滨麦草。综合基因来源、分子检测及染色体位点等方面的分析,认为Yr Elm可能是一个新的抗条锈病基因。用该基因两侧最近两个标记Xcfd35和Xgwm161检测68个甘肃和黄淮麦区小麦品种(系),10个(14.7%)品种能扩增出与M852-1相同的条带。进一步进行抗病性及系谱分析表明,这10个品种均不含Yr Elm。本研究结果为利用Yr Elm进行分子标记辅助育种和进一步的精细定位奠定了基础。

Wheat stripe rest, caused by Puccinia striiformis f. sp. tritici （Pst）, is one of the most important diseases of wheat worldwide, especially in China. Wheat relatives are important donors of resistance genes against this disease in wheat breeding program. M852-1, a wheat-Elymus mollis translocation line, is highly resistant to seven main Pst races or new pathotype of China （CYR29, CYR31, CYR32, CYR33, Su11-4, Su11- 7 and V26）, and is a preferable stripe rust resistant material. F1, F2, F3 and BC1generafions derived from cross M852-1/Mingxian169 were tested with prevalent Pst race CYR33. The genetic analysis results indicated that the resistance of M852-1 to CYR33 was controlled by a single recessive gene, tentatively designated as YrElm. The resistance gene was mapped using a F2 population from M852-1/Mingxian169 and bulked segregant analysis （BSA）. YrElm was linked with five simple sequence repeat （SSR） markers, Xcfd35, Xgwm161, Xwmc630, Xgwm533 and Xcfd34, which were located on wheat chromosome 3DS. The genetic distances of the closestflanking markers, Xcfd35 and Xgwm161, were 6.5 cM and 4.2 cM, respectively. Pedigree analysis, chromosomal location and molecular test suggested that YrElm might be a novel stripe rust resistance gene which was derived from Elymus mollis. Two closest flanking SSR markers, Xcfd35 and Xgwm161, were used to test 68 wheat cultivars from Gansu and Huanghuai wheat region. The results showed that ten （14.7%） cultivars had the same polymorphic bands as M852-1. However, resistance identification and pedigree analysis suggested that these ten cultivars might not carry the stripe rust resistance gene YrElm. The polymorphic SSR markers identified in this research can be useful in wheat molecular marker select breeding and fine mapping.