基于SSR的西南地区野生菰资源遗传多样性及遗传结构分析

摘要

Zizania latifolia (Griseb.) Turcz.is a member of tribe Oryzeae and possesses numerous traits valuable for rice breeding.Genetic diversity and genetic structure of 25 local wild rice populations of Z.latifolia collected from Southwest China were investigated using SSR (simple sequence repeat) markers.Based on Popgene 1.32 it was observed that the average polymorphism percentage bands (PPB) of the 19 pairs of respinformative SSR primers was 100%,the numbers of alleles (Na) and the effective number of alleles (Ne) were 2 and 1.608,ectively.The average indexes of Nei's genetic diversity (He) and Shannon's information (I) were 0.349 and 0.517,respectively.The genetic similarity index and genetic distance of the 25 local wild rice populations ranged from 0.603 6-0.937 2 and 0.064 8-0.504 8,respectively.Cluster analysis showed that the 25 wild populations of Z.latifolia could be classified into ten groups at the threshold of 0.196 could the first group can be further classified into four subgroups at the threshold of 0.238.The gene flow between populations was 0.788 and an AMOVA analysis showed that 88.87% of the total genetic diversity was within populations and the rest (11.13%) among populations.This work showed that Z.latifolia resources in Southwest China had a rich genetic diversity,genetic drift played a role in the genetic differentiation process,and there was no significant association between the phylogenetic relationship and the geographic locations in the Z.latifolia populations.It can be speculated that natural selection has played an important role in the genetic differentiation process of Z.latifolia resources in southwest China.This study deepens understanding of the genetic evolution of Z.latifolia in Southwest China and at the same time provides certain theoretical basis for protection of this wild rice germplasm resource.%菰属(Zizania latifolia (Griseb.) Trucz.)为禾本科水稻近缘属之一,携带水稻育种所需的多种优良性状基因.采用本项目前期筛选出来的19对水稻SSR标记,对我国西南地区4省市25个野生菰居群进行了遗传多样性及遗传结构分析.POPGEN32软件分析显示,19对SSR标记扩增谱带的多态性条带百分比为100%;在物种水平上,西南地区野生菰等位基因数和有效等位基因数分别为2和 1.608,Nei's基因多样性指数和Shannon's多样性信息指数分别为0.349和0.517;25个野生菰居群间的遗传相似性系数为0.603 6~0.937 2,遗传距离介于0.064 8~0.504 8.NTsys2.10e聚类分析结果显示,阈值在0.196时,25个居群聚被分成10组;阈值为0.238时,第Ⅰ组可再聚分为4个亚组.居群间平均基因流为Nm=0.788.AMOVA分析结果显示,西南地区野生菰88.87%的变异存在于居群内部,11.13%的变异存在于居群间.研究结果表明,西南地区野生菰资源有着丰富的遗传多样性,遗传漂变在西南地区野生菰植物的遗传分化中起到了一定的作用,各居群的聚类结果与地理分布无明显相关性.推测选择压力可能在西南地区野生菰遗传分化中起着重要作用.研究结果有助于加深对我国西南地区乃至更大范围内野生菰资源遗传进化的认识,同时为野生菰种质资源保护提供理论依据.