基于ISSR标记的云南桑褐斑壳丰孢菌遗传多样性分析

Genetic Diversity of Phloeospora maculans on Mulberry in Yunnan Based on ISSR Markers

为明确云南省桑褐斑病病原菌桑褐斑壳丰孢菌(Phloeospora maculans)的遗传多样性及亲缘关系,采用ISSR分子标记对分离自云南省不同县市的58株桑褐斑壳丰孢菌进行遗传多样性分析。结果显示,物种水平上,Nei’s多样性指数H为0.276 3,Shnanon信息指数I为0.421 0,表明云南桑褐斑病病原菌具有丰富的遗传多样性;遗传距离分析表明,保山和曲靖的菌株种群遗传相似系数最高为0.945 0,亲缘关系最近,保山和蒙自的菌株种群遗传相似系数最低为0.870 6,亲缘关系相对较远;居群每代迁移数N_(m)为1.889(>1),表明不同地理种群间存在一定的基因流动;利用NTSYS软件按UPGMA方法聚类分析,58株桑褐斑壳丰孢菌的遗传相似系数在0.69~1.00之间,当相似系数为0.73时,可将58个供试菌株分为4个类群,但菌株并没有按地理来源聚为不同的组,表明菌株之间的遗传多样性与其地理来源无明显的相关性。

In order to understand the genetic diversity and relationship of Phloeospora maculans, the pathogen of mulberry brown spot disease in Yunnan, the inter-simple sequence repeat(ISSR) molecular marker were applied to analyze the genetic diversity of 58 strains isolated from mulberry brown spot disease pathogens in different counties or districts in Yunnan. The results showed that the Nei’s gene diversity index(H) and the Shannon’s information index(I) were 0.276 3 and 0.421 0 respectively at the species level, which indicated that the genetic diversity of mulberry brown spot disease pathogens in Yunnan was considerably abundant. Genetic distance analysis indicated that the genetic similarity coefficient of strains in Baoshan and Qujing was the highest(0.945 0), which means the genetic relationship between them was the closest. The genetic similarity coefficient of strains in Baoshan and Mengzi was the lowest(0.870 6), which means their genetic relationship was relatively far. The number of population migration per generation N_(m)=1.889(>1), indicating that there was a certain gene flow between different geographic populations. According to UPGMA cluster analysis with NTSYS software, the genetic similarity coefficient of 58 P. maculans strains was between 0.69 and 1.00. When the genetic similarity coefficient was 0.73, the 58 P. maculans strains could be classified into 4 groups, but the strains were not clustered into different groups according to geographical origins, indicating that there was no significant correlation between the genetic diversity and the geographical origins.