21株马特组镰刀菌遗传多样性的ISSR分析

为明确马特组镰刀菌种间和种内的遗传差异与亲缘关系,本文利用ISSR分子标记技术对21个马特组菌株进行了遗传多样性分析.结果表明:利用筛选出的15条引物对3种供试菌株进行扩增,共扩增出239条条带,其中多态性条带230条,多态性位点比例为96.2％,平均每条引物产生条带数为15.3条.21个菌株间的遗传相似系数范围为0.494～0.933,平均为0.640.在遗传相似系数为0.593时,供试的21株马特组镰刀菌可明显分成2个ISSR类群(IG),IG-Ⅰ包括1～17号菌株,为Fusarium solani和F solani var.coeruleum;IG-Ⅱ包括18 ～21号菌株,全部为F.ventricosum.在遗传相似系数为0.933时,供试的21个菌株可被全部区分开.供试的镰刀菌基因组在SSR区域具有丰富的多态性;ISSR类群划分与菌种分类之间存在一定相关性,但与菌株的地理来源没有相关性;而同一类群中,不同菌株之间的遗传相似性与菌株的地理来源存在一定的相关性.同一地区同种寄主的相同菌种,其菌株间也存在一定的遗传差异.

Genetic diversity of 21 fusarium strains in Section Martiella based on ISSR analysis

In order to understand the genetic difference and phylogenic relationship within and among the Fusarium species in Section Martiella, the genetic diversity of 21 Fusarium strains in the section was examined by inter-simple sequence repeats (ISSR). Fifteen selected ISSR primers were adopted to do amplification, and a total of 239 bands were amplified, among which, 230 (96.2%) were polymorphic, with an average of 15.3 polymorphic bands per primer. The genetic similarity ranged from 0.494 to 0.933, with an average of 0.640. All the test strains were clustered into two groups at genetic similarity of 0.593. The strains 1-17 were grouped into IG-I, belonging to Fusarium solani and F. solani var. coeruleum, while the strains 18-21 were grouped into IG-II, belonging to F. ventricosum. All the 21 strains could be entirely distinguished at genetic similarity of 0. 933. The SSR loci in the Fusarium genomes were rich in polymorphism. The ISSR grouping had definite correlation with the species classification, but less correlation with the geographic origin of the strains. Within the same ISSR groups, there existed definite correlation between the genetic similarity and the geographic origin of the strains. Within the same species collected from the same regions and same host plants, there existed definite genetic difference among the strains of the same species.