甘肃省甘谷县小麦条锈菌群体遗传结构分析

Analysis of genetic structure of a local Puccinia striiformis f.sp.tritici population in Gangu County,Gansu Province in China

为明确我国小麦条锈菌Puccinia striiformis f. sp. tritici主要越夏地区的群体遗传结构及演变情况,利用SSR荧光检测技术,对甘肃省甘谷县2013-2015年期间连续5个小麦生长季采集的141株小麦条锈菌单孢系基因组DNA进行分子标记分析,对小麦条锈菌季节亚群的遗传多样性进行分析。结果表明,甘谷地区小麦条锈菌的遗传多样性丰富,有效等位基因数为1.71,Shannon信息指数为0.66,2014年秋季(2014A)亚群体的基因型多样性低于其余亚群体。分子变异方差分析结果显示,小麦条锈菌季节亚群体间变异仅占21%,变异主要出现在亚群体内部,表明甘谷地区各季节亚群体间遗传分化水平差异较小,小麦条锈菌群体在一个小范围内基本能维持稳定状态。主坐标分析(PCoA)、遗传分化、基因流以及共享基因型分析均表明2014年秋季(2014A)亚群体的遗传结构与相邻季节亚群体存在一定差异,表明越夏过程对甘谷地区个别年份小麦条锈菌群体周年稳定性造成较大的影响,越冬过程对小麦条锈菌群体的影响相对较小,春季受外来菌源干扰的可能性较低。

To clarify the population genetic structure and seasonal evolution of Puccinia striiformis f.sp. tritici in a tiny area of main over-summering regions in China, genomic DNA of 141 isolates of P.striiformis f. sp. tritici sampled from 2013 spring to 2015 spring in Gangu County, Gansu, China was amplified with 12 pairs of SSR markers. The results showed that genetic diversity of P. striiformis f. sp.tritici in Gangu area was abundant, and the effective allele number was 1.71, and Shannon’s information index was 0.66. The genotypic diversity of subpopulation in autumn 2014(2014 A) was significantly lower than that in other seasons. The analysis of molecular variance showed most of the variation occurred within the seasonal subpopulation,and only 21% variance existed among subpopulations, which indicated P. striiformis f. sp. tritici population could maintain stability in a local area over seasons. Principal coordinate analysis, genetic differentiation analysis, gene flow and shared genotype analysis all showed that subpopulation of 2014 autumn(2014 A) had genetic divergence with other adjacent seasonal subpopulations, which indicated over-summering progress might interrupt the stability of population genetic structure, however not affected by the over-wintering progress, suggesting the spring sources mainly come from local area.