绿豆SSR标记的开发及遗传多样性分析

Development of SSR markers and genetic diversity analysis in mung bean

SSR标记以其数量丰富、多态性好、共显性遗传等优点在基础研究和育种工作中发挥了重要作用,但目前绿豆基因组中的SSR标记依然较少。本研究将磁珠富集法和测序技术相结合高通量检测绿豆基因组SSR位点,鉴定出3,275,355个SSR位点,开发了2742个SSR标记。选取其中157个SSR进行PCR验证,发现有90个(57.33%)标记在10份材料中表现出多态性。挑选40个条带清晰、多态性高、染色体上均匀分布的标记对90份绿豆资源进行遗传多样性分析,单个位点检测到的等位变异数为2~8个,平均为3.0个,有效等位基因数为1.31~4.21个,平均为2.16。Nei’s基因多样性指数在0.23~0.76之间,平均为0.51。多态性信息含量为0.22~0.72,平均为0.43。聚类分析将90份材料分为2个类群,包含4个组。第I组主要由北方资源组成,第Ⅱ组种质来源较为分散,第Ⅲ组主要由山东的资源构成,第Ⅳ组包含多数河北的种质资源。本研究开发的多态性SSR标记不仅可以用于绿豆种质资源的遗传多样性分析,也将在高密度遗传图谱构建、基因定位和分子标记辅助育种中发挥重要作用。

SSR markers play an important role in basic research and crop breeding due to their advantages of large number, high polymorphism and co-dominant inheritance. However, there are still few SSR markers available in mung bean. In this study, the magnetic bead enrichment method and sequencing technology were combined to identify the SSR loci of mung bean in high throughput, a total of 3,275,355 SSR loci were found, and 2742 markers were developed. A total of 157 markers were selected for validation by PCR method, 90 (57.33%) showed polymorphic among 10 mung bean accessions. Forty SSR markers with clear PCR products, high polymorphism and uniform distribution on chromosomes were selected to evaluate the genetic diversity among 90 mung bean accessions. The number of alleles per marker varied from two to eight, with an average of three. The effective number of alleles ranged from 1.31 to 4.21, with a mean value of 2.16. The Nei’s gene diversity was between 0.23 and 0.76, with an average of 0.51. Polymorphism information content was between 0.22 and 0.72, with a mean of 0.43. Cluster analysis distributed 90 materials into two clusters, including four groups. The germplasm of group Ⅱ came from several areas, while those of groups I and Ⅲ were mainly from North China and Shandong province, respectively. Most of the gerplasm from Hebei province were clustered in Group Ⅳ. These polymorphic SSR markers will be valuable for genetic diversity analysis, high-resolution genetic linkage maps construction, gene mapping and marker assisted selection in mung bean breeding.