基于ISSR分子标记的黄花倒水莲遗传多样性分析

Genetic diversity analysis of Polygala fallax based on ISSR molecularmarkers

旨在揭示黄花倒水莲资源的遗传多样性,分析其遗传差异,为黄花倒水莲的良种选育提供理论基础。以荷包山桂花居群为外类群,利用简单重复序列间扩增(Inter simple sequence repeat,ISSR)分子标记对来源于10个地区的黄花倒水莲自然居群进行遗传多样性和亲缘关系分析。结果显示,用11条引物共扩增得到132条条带,其中91条为多态性条带(PPB),多态性条带比例为68.94%。在物种水平上,黄花倒水莲10个居群的Nei’s基因多样性指数(H)、Shannon多样性指数(I)分别为0.1637、0.2501,表现出较高的遗传多样性,而在居群水平上,H、I的均值分别为0.0634、0.0988,表现出偏低的遗传多样性。Nei’s遗传多样性和分子方差分析(AMOVA)结果表明,黄花倒水莲的遗传变异主要发生在居群间,遗传分化程度较高(基因分化系数=0.6109,基因流=0.3185)。遗传一致度及聚类分析结果显示,黄花倒水莲各居群间的亲缘关系较近(遗传距离为0.032~0.182),与荷包山桂花居群的亲缘关系较远(遗传距离为0.428~0.536),在遗传一致度为0.630处可以将黄花倒水莲与荷包山桂花区分开,在遗传一致度为0.867处可以将10个黄花倒水莲居群分为3类。由于黄花倒水莲居群水平上的遗传多样性水平较低,今后应对黄花倒水莲野生资源进行合理利用与保护。

The aim of this study is to reveal the genetic diversity of Polygala fallax Hemsl germplasm resources,and analyze their genetic differences,so as to provide theoretical basis for the selection and breeding of Polygala fallax Hemsl germplasm resources.Taking Polygala arillata Buch as the outer group,the inter-simple sequence repeat(ISSR)molecular markers were used to explore the genetic diversity and genetic relationship of natural populations of Polygala fallax Hemsl from ten regions.The results showed that a total of 132 bands were amplified with 11 primers,including 91 polymorphic bands(PPB),and the proportion of PPB was 68.94%.At the species level,Nei’s gene diversity index(H)and Shannon’s diversity index(I)were 0.1637 and 0.2501,respectively,showing high genetic diversity.At the population level,the mean values of H and I were 0.0634 and 0.0988,respectively,showing low genetic diversity.The results of Nei’s genetic diversity and molecular variance analysis(AMOVA)showed that the genetic variation was mainly distributed among populations,with a large level of genetic differentiation(gene differentiation coefficient was0.6109,gene flow was 0.3185).The genetic identity and clustering results indicated that the genetic relationship between the populations of Polygala fallax Hemsl was relatively close(genetic distance was 0.032-0.182),and the genetic relationship with Polygala arillata Buch was relatively far(genetic distance was 0.428-0.536).At the level of genetic identity of 0.630,Polygala fallax Hemsl and Polygala arillata Buch(YN)could be separated.Ten populations of Polygala fallax Hemsl could be divided into three types at 0.867.In view of the relatively low level of genetic diversity in the population of Polygala fallax Hemsl,the wild resources should be rationally utilized and protected in the future.