西藏林芝麦类条锈病菌群体多样性分析

Population Diversity of Puccinia striiformis in Linzhi of Tibet

为了解西藏麦类条锈病菌种群结构,测定了来自西藏林芝及邻近地区的70个菌株生理小种。结果表明,在检测出的23种小种类型中,林芝地区病菌分属水源致病类群及CY28以前的致病类型,水-2和水-5为林芝优势小种,但在2009年CY28以前类型的现频率高达32.35%。筛选出E2M2、E3M3、E4M6、E7M6等4对Eco R I/Mse I引物组合,对各条锈病菌株基因组DNA进行AFLP分析,共扩增出141条可统计的条带,其中多态性条带为39条,多态率为27.65%。经AFLP分析,70个参试菌株的遗传相似系数范围为0.55～1.00。当遗传相似系数为0.748时,所有菌株可分为4组。其中来自林芝的菌株大部分被聚类在A组的第一、第二亚组,而A组第四亚组、B、和D组为西藏特有遗传类型。来自四川阿坝州的菌株均属于A组第一亚组,来自四川甘孜和凉山的菌株均属于A组第二亚组。来自云南丽江的菌株分属A组第三亚组和C组。毒性分析和AFLP分析均表明,西藏条锈病菌是一个相对独立的群体,但和邻近地区特别是四川越夏区有一定的亲缘关系。

To assess the genetic diversity of Puccinia striiformis in Linzhi of Tibet,virulence to the differential host varieties of Chinese physiologic races of yellow rust fungus and AFLP polymorphism of 70 isolates collected from Linzhi and neighboring areas in Sichuan and Yunnan were investigated.The result showed that totally 23 virulent types were identified,and Su-2 and Su-5 were the predominant virulence types in Linzhi,which were the highest at 32.35 % before CY28 in 2009.Cluster analysis of the virulence spectra of 70 tested isolates to the differential varieties showed that there were distinct virulent types for Linzhi.4 pairs of AFLP primers linked to Eco R I /Mse I restrict enzyme combination were selected for the yield of good polymorphism.Totally 141 AFLP bands including 39 polymorphic bands were detected.The polymorphic rate was up to 27.65 %.The genetic similarity varied between 0.55-1.00.70 isolates were clustered into four groups respectively as A,B,C and D when the genetic similarity was at 0.748.The majority of the isolates from Linzhi were clustered into the Subgroup I,and II in Group A while Group B,D as well as the Subgroup IV in Group A were distinct genetic types only found in Linzhi.All of the isolates from Aba in Sichuan were in Subgroup I.The isolates from Ganzi and Liangshan were all in Subgroup II.The isolates from Lijiang in Yunnan were in Group C and Subgroup III in Group A.Both virulence and AFLP analysis indicated an independent population of P.striiformis sp.tritici in Linzhi with phylogenetic links with the fungus in the neighboring areas,especially that in the over-summer areas in Sichuan.