用SSR分子标记分析无融合生殖龙须草的遗传多样性

Analyzing the genetic diversity of apomictic Eulaliopsis binata with SSR markers

采用磁珠富集法构建龙须草微卫星文库,并开发出27对具有多态性的SSR引物,利用其中具有扩增差异的8对稳定的SSR引物,对龙须草11个居群和71个单株进行聚类分析。结果表明：居群间共检测到123个等位基因,每对引物可以稳定检测到6~34个多态性片段。居群间的遗传相似系数为0.70~0.97,聚类分析将11个居群划分为4个类群,表明龙须草大多数居群之间的分化程度较低,与无融合生殖的特性相吻合。采用UPGMA法将分散在龙须草11个居群的71个单株分为3个群,与以居群为单位的研究结果相近;但是,星子居群内的3个单株、洋县居群的1个单株分别与本居群亲缘关系较远并与其他居群亲缘关系较近,显示在这2个居群内不同单株间存在较大的遗传差异,这种差异可能是居群内单株间无融合生殖程度不同所致。因此,在这2个居群内可能存在有性生殖频度较高的单株。

Eulaliopsis binata, a newly found apomictic species belonging to Poaceae,was proven to have diverse degree of apomixis among populations as well as individual. A microsatellite-enriehed librar- y was constructed by capture with streptavidin coated-beads magnetic beads adsorption. Twentyseven pairs of polymorphic SSR primer were developed. Genetic diversities of 11 populations and 71 individuals of E. binata were analyzed by 8 SSR primers producing 123 alleles. Each SSR marker amplified 6-34 polymorphic fragments. The eleven populations of E. binata had a genetic similarity coefficients ranging from 0. 70 to 0. 97 and could be classified into 4 clusters, indicating the most populations of E. binata had high similarity consistent with its apomictic reproduction mode. By UPGMA analysis,71 E. binata indi- viduals could be classified into 3 groups consistent with results of population classification. However, three individuals from Xingzi population and one individual from Yangxian population were deviated from their own clusters of population respectively and nested in a different location,indicating that the genetic diversity was appeared in different individual of same population and the genetic difference may be reflected the varying degrees of apomixis of plant.