轮枝镰孢SSR标记开发及在玉米分离群体遗传多样性分析中的应用

【目的】开发轮枝镰孢（Fusarium verticillioides）的SSR标记，为轮枝镰孢遗传多样性研究提供技术支持。【方法】利用Fastpcr在轮枝镰孢基因组中查找符合条件的SSR位点，采用Primer5.0软件设计引物，利用NTSYS及Popgene分析来自玉米的轮枝镰孢单孢分离物群体的PCR扩增结果。【结果】共设计有效扩增SSR引物158对，经筛选，109对（69.0%）可扩增出2条及以上的条带，其中55对引物（34.8%）多态性较好，可扩增出3条及以上的条带。从11条已组装的轮枝镰孢染色体上各选出2对多态性引物，计22对引物，对66株轮枝镰孢玉米分离物进行扩增，共获得125个等位变异，变异范围为2—11个，平均为5.68个。轮枝镰孢玉米分离物之间Nei’s基因多样性指数为0.1139—0.8687，平均为0.6199，表现出较高的遗传多样性。【结论】基于轮枝镰孢基因组序列开发的SSR标记具有很好的多态性，可用于轮枝镰孢的遗传多样性分析。用22对SSR引物扩增，以遗传相似系数0.3进行划分，可将66株轮枝镰孢玉米分离物分为3群；中国轮枝镰孢玉米分离物的遗传多样性与地理分布无相关性。

SSR Marker Development and Analysis of Genetic Diversity of Fusarium verticillioides Isolated from Maize in China

【Objective】 The objective of this study is to analyze genetic diversity of Fusarium verticillioides and to develop SSR markers for this fungus.【Method】 Fastpcr was used for searching SSRs in genomic sequence of F.verticillioides.The sequences including suitable SSRs were selected to design primers using Primer5.0.The NTSYS and Popgene programs were used to analyze genetic diversity of maize isolates of F.verticillioides.【Result】 Among the 158 primer pairs designed,109 pairs(69.0%) were able to amplify 2 or more alleles against discretionary F.verticillioides isolates originating from single conidium.Of them 55 pairs(34.8%) amplified 3 or more alleles.In 11 chromosomes assembled 22 primer pairs,two pairs for one chromosome,were selected for genetic diversity analysis of 66 isolates of F.verticillioides from maize.In 22 SSR loci,a total of 125 alleles(2 to 11 alleles amplyfied by per primer pair) were detected with an average of 5.68 alleles.The Nei’s gene diversity,ranged from 0.1139 to 0.8687 with an average mean of 0.6199,indicated high genetic diversity in F.verticillioides isolates from various geographic regions.【Conclusion】Based on genome information of F.verticillioides,109 SSR markers were developed and showed high polymorphism and high diversity among F.verticillioides isolates.By amplyfying with 22 SSR primer pairs,66 isolates of F.verticillioides from maize were seperated into 3 groups on 0.3 coefficient.The relationship between genetic diversity and geographical distribution did not show correlation in isolates of F.verticillioides from maize in China.