甘肃玉米茎腐病病菌禾谷镰孢复合种遗传多样性

Genetic Diversity of Fusarium graminearum Species Complex from Maize Fusarium Stalk Rot in Gansu

为阐明甘肃省玉米茎腐病优势致病菌禾谷镰孢复合种地理群体的遗传多样性,2015年和2017年从甘肃省4个生态区采集茎腐病样本,经组织分离及鉴定,选取代表性禾谷镰孢复合种菌株114株,采用SSR和VNTR引物结合POPGENE version1.32及NTSYSpc 2.11,进行群体间遗传多样性及亲缘关系的聚类分析。结果表明,共检测到多态性位点26个,片段大小为50~300 bp,平均每对引物扩增条带数为1.44。4个地理种群平均等位基因数为1.9519,有效等位基因数为1.7140,Nei’s基因多样性指数为0.3939,Shannon信息指数为0.5691,多态性位点数为24.75,多态位点百分率为95.19%。4个地理种群的Nei’s遗传相似度为0.8880~0.9674,遗传距离为0.0331~0.1188。分析发现,禾谷镰孢复合种的种群遗传变异主要来自种群内部,占总变异的90.71%。在遗传相似系数0.9380附近,禾谷镰孢复合种种群聚为3大类群,陇南地区为第Ⅰ类群,河西走廊为第Ⅱ类群,陇东地区和陇中地区为第Ⅲ类群。

In order to clarify the genetic diversity of the geographical population of Fusarium graminearum species complex(FGSC),the dominant pathogen of maize stalk rot in Gansu Province,samples were collected from four ecological regions of Gansu Province in 2015 and 2017.After tissue isolation and identification,114 representative strains of FGSC were selected,and the genetic diversity and genetic relationships among populations were analyzed using SSR and VNTR primers combined with POPGENE version1.32 and NTSYSpc2.11,respectively.The results showed that a total of 26 polymorphic loci were detected,the fragment size was between 50 and 300 bp,and the average number of bands amplified by each pair of primers was 1.44.The average number of alleles in the four geographical populations was 1.9519,the effective number of alleles was 1.7140,the Nei’s genetic diversity index was 0.3939,the Shannon information index was 0.5691,the number of polymorphic loci was 24.75,and the percentage of polymorphic loci was 95.19%.The Nei’s genetic similarity between the four geographical populations ranged from 0.8880 to 0.9674,with a genetic distance of 0.0331 to 0.1188.The analysis showed that the genetic variation associated with FGSC came mainly from within the population,accounting for 90.71%of the total variation.Near the genetic similarity coefficient of 0.9380,the geographic populations of FGSC were divided into three large groups:groupⅠin Longnan,groupⅡin the Hexi Corridor,and groupⅢin the Longdong and Longzhong areas.