尖孢镰刀菌致病性菌株遗传多样性的ISSR分析

Genetic Diversity of Pathogenic Fusarium oxysporum Strains by ISSR Markers

致病性尖孢镰刀菌（Fusarium oxysporum）是一种世界性分布的作物土传病原真菌,为明确其不同寄主及专化型菌株遗传差异性和亲缘关系,利用ISSR分子标记技术对来源于不同寄主（专化型）及地理分布的43个菌株进行了遗传多样性分析。结果表明,供试的15条引物通过ISSR-PCR扩增,共扩增出147条条带,其中多态性条带为144条,平均多态性条带达98.0%。43个菌株的聚类结果表明,各菌株间的遗传相似系数为0.67~0.97,且遗传多样性与其寄主和地理来源没有明显的相关性。进一步将供试菌株中葫芦科与茄科作物尖孢镰刀菌分别进行聚类分析,当遗传相似系数为0.84时,16个葫芦科的菌株可分为6个ISSR类群;当遗传相似系数为0.77时,16个茄科的菌株亦可分为6个ISSR类群;且均表现为相同寄主或专化型菌株因地理来源不同,被归属于不同的ISSR类群,说明寄主或专化型相同的菌株与地理来源存在一定的相关性。

Pathogenic Fusarium oxysporum is one of the most common soil-borne fungal pathogens all over the world. To specify genetic difference and phylogenetic relationship of F. oxysporum strains, the genetic diversity of43 strains with different host and geographic origin or formae speciales strains was analyzed using the ISSR-PCR molecular marker technique. The results showed that 147 fragments were amplified from 43 strains by 15 tested primers. Among them, the polymorphic band was 144, which accounted for 98.0% in the total amplified fragments. The ISSR analysis showed that genetic similarity coefficient was 0.67-0.97, suggesting a high genetic variability within 43 strains. However, the results did not reveal a clear relationship between variability and the host/geographic origin. The isolates from cucurbitaceae and solanaceae crops were further performed the cluster analyses of genetic variability, respectively. At the level of 0.84, 16 isolates from cucurbitaceae crops could be obviously divided into six ISSR groups. At the level of 0.77, 16 isolates from solanaceae crops could be also obviously divided into six ISSR groups. Moreover, these F. oxysporum isolates from the same host or formae speciales strains could be divided into different ISSR groups due to their different geographic origin. The results indicated that there was a relationship in a certain degree between variability and geographic origin within the isolates from the same hosts or the same formae speciales strains.