大麦抗条纹病基因的定位分析

为发掘大麦中抗条纹病的新基因,采用三明治法通过人工接种大麦条纹病菌Pyrenophora graminea强致病力菌株QWC对甘啤2号(免疫)与Alexis(高感)杂交F_1代及F_2代分离群体进行抗性遗传分析,利用群体分离分析法鉴定与抗病基因连锁的SSR标记,并通过QTL IciMapping软件构建遗传连锁图谱完成对抗病基因的定位。结果显示,甘啤2号与Alexis杂交F_1代对大麦条纹病菌强致病力菌株QWC表现为免疫,F_2代表现3∶1抗感分离,表明甘啤2号对菌株QWC的抗性由1个显性抗性基因控制,将该抗病基因暂命名为Rdg3;该基因位于大麦7H染色体上的SSR标记Bmag206和Bmag7之间,与二者的遗传距离分别为1.78 cM和2.86 cM。经与已定位于7H染色体上的抗病基因比较,发现Rdg3是一个新的抗条纹病基因,可作为大麦抗病育种的新种质资源。

Molecular mapping of a gene for resistance to barley leaf stripe

In order to identify new resistance genes to Pyrenophora graminea in barley, the resistance evaluation of F₁ and F₂ generations from the crosses between Ganpi 2 (immune) and Alexis (high susceptible), as well as the parents, were carried out with sandwich method. Based on bulk segregation analysis and microsatellite markers analysis, SSR marker linked with resistance genes was identified, and then QTL IciMapping software was used to calculate the genetic distance, construct genetic linkage map, and map resistance gene. The results of resistance evaluation showed that F₁ population was immune, and the ratio of resistance/susceptible was 3:1 in F₂ generation. This indicated that the barley leaf stripe resistance in Ganpi 2 was conferred by a single dominant gene, which was designated as Rdg3 temporarily. The resistance gene Rdg3 located on chromosome 7H was between SSR markers Bmag206 and Bmag7, and the genetic distance was 1.78 cM to Bmag206 and 2.86 cM to Bmag7. Furthermore, based on the comparison with resistance gene mapped on 7H, Rdg3 was a novel barley leaf stripe resistance gene, which might serve as a new germplasm in barley resistance breeding.