云南省小麦条锈菌不同地理亚群体的遗传结构分析

The genetic structure of wheat stripe rust pathogen Puccinia striiformis f. sp. tritici from geographical subpopulations in Yunnan Province

为明确云南省小麦条锈菌(Puccinia striiformis f. sp. tritici,Pst)在不同地理环境下的群体遗传结构,通过3种不同地理亚群体划分方式,即以县域(Group C)、区域(Group R)和海拔(Group E)对云南省537个Pst单孢系进行不同层次的群体划分,并利用12对SSR引物对其进行遗传多样性和群体遗传结构分析。结果显示,云南省Pst的遗传多样性水平在Group C的亚群体之间差异最大,且来自滇中及滇东北地区的Pst群体的遗传多样性较高。Group R和Group E的亚群体基因流及遗传分化结果表明,云南省Pst菌源交流频繁、遗传分化较小。系统进化树分析结果显示,滇东北与滇中Pst群体类似,滇东南与滇西Pst群体类似。Pst遗传组分呈现出由东向西、由北向南和自低海拔向高海拔变化的趋势,与云南省自东南向西北逐渐攀升的地形及地势吻合。Mantel检验结果表明地理距离与遗传距离不存在相关性,在8个县域亚群体、2个区域亚群体检测到有性生殖。表明来自滇中和滇东北地区的Pst群体具有更高的遗传多样性,地理隔离可能是滇西地区遗传多样性较低的成因,遗传分化发生在县域之间,全省Pst群体存在两大空间遗传结构,不同海拔之间的菌源交流频繁,推测云南省Pst群体为有性重组和无性繁殖的混合群体。

In order to characterize the genetic structure of wheat stripe rust pathogen Puccinia striiformis f.sp. tritici(Pst) sampled from various geographical regions in Yunnan Province, 537 isolates were grouped by three ways by county(Group C), by region(Group R), and by elevation(Group E) into three hierarchy geographical subpopulations. The genetic diversity and population genetic structure were analyzed using 12 pairs of SSR markers. The results of genetic diversity showed that there were great differences among subpopulations in Group C, the isolates from central Yunnan(YC) and northeastern Yunnan(YNE) had highest genetic diversity. Subpopulations in Group R and Group E possessed strongly gene flow and littlegenetic differentiation. The phylogenetic tree revealed that subpopulations from YNE were similar to those from YC, and subpopulations from southeastern Yunnan(YSE) were similar to those from western Yunnan(YW). Genetic components varied from east to west, from north to south, from low altitude to high altitude, consistent with the characteristics of topography which gradually climb from southwestern to northwestern Yunnan. The results of Mantel test revealed that there were no significant correlations between the geographic distance and genetic distance, and sexual reproduction was detected in eight county-wise subpopulations, and two regional subpopulations. The results indicated that the isolates from YC and YNE possessed higher genetic diversity, distance isolation would be the reason for the lowest genetic diversity of subpopulations in YW, genetic differentiation occurred among counties, there were two spatial genetic structures within the province, there were frequent gene exchange of Pst sources from differing elevations, inferring Yunnan Pst as a mixed population with sexual and clonal reproduction.