小麦条锈病抗源S2199抗病基因分子标记及其与Yr5的关系

Molecular Characterization of a Stripe Rust Resistance Gene from Wheat Line S2199 and Its Allelism with Yr5

选用含有小麦条锈病抗源S2199的杂交组合(3338/14119//S2199)F4/2*陕354F2代519个单株和其F3家系对S2199抗条锈病基因进行遗传分析和分子标记定位。结果表明,来自条锈病抗源S2199的条锈病抗性为显性单基因控制,暂命名该基因为YrS2199。采用BSA法和SSR分子标记分析,筛选到与抗条锈病基因YrS2199连锁的SSR分子标记Xdp269和Xgwm120,连锁距离分别为0.7cM和11.0cM,并将其定位在2BL染色体末端上。这两个分子标记为S2199抗条锈病基因的分子标记辅助选择和抗病基因聚合提供了便利。通过等位性检测和14个条锈菌生理小种分小种鉴定,初步明确了S2199含有的抗条锈病基因可能是Yr5或其等位基因。抗源S2199是一个具有优良农艺性状的材料,为小麦育种提供了一个新的Yr5或其等位基因供体。

Yellow rust, caused by Puccinia striiformis f. sp. tritici （PST）, is one of the most devastating diseases in common wheat （Triticum aestivum L.） worldwide. Molecular markers are powerful tools in marker-assisted selection, gene pyramiding and gene cloning of important crop traits, especially for disease resistance. The objectives of this study were to develop tightly linked molecular marker of a yellow rust resistance gene against the prevalent Chinese races of Puccinia striiformis f. sp. tritici in an improved wheat line S2199 and to characterize its allelism with Yr5. Genetic analysis indicated that a single dominant gene was responsible for the yellow rust resistance in S2199, temporarily designated YrS2199. By screening 1 856 pairs of SSR primers, two markers—Xdp269 and Xgwm120 were found to be linked to the yellow rust resistance gene, with genetic distance of 0.7 cM and 11.0 cM, respectively. SSR marker Xgwm120 has been genetically and physically mapped on 2BL chromosome arm in wheat. By using Chinese Spring nullisomic-tetrasomics, ditelosomics and deletion lines of homoeologous group 2, Xdp269 was physically mapped on the terminal bin （0.89–1.00） of chromosome arm 2BL. Both allelism test of 700 F2 plants from the cross YrS2199/Yr5 and seedling tests of YrS2199 and Yr5 on 14 PST isolates indicated that YrS2199 and Yr5 are likely to be the same gene or allelic genes. The YrS2199 tightly linked SSR marker Xdp269 could be used as potential tool in cloning the yellow rust resistance gene or marker assisted breeding program.