新疆胀果甘草遗传多样性的ISSR分析

Genetic diversity ISSR analysis of Glycyrrhiza inflata from Xinjiang

目的揭示新疆塔里木盆地分布的野生胀果甘草Glycyrrhiza inflata的遗传多样性和种群遗传结构。方法利用ISSR分子标记方法,对来自新疆南疆不同地理方位的胀果甘草6个种群总计167个个体进行分析。结果对胀果甘草6个种群共筛选出46条引物,扩增获得193条多态条带,多态位点比率(PPL)为69.68%,Nei’s遗传多样性指数(H)为0.2722,Shannon多样性指数(I)为0.4010;Nei’s总种群遗传多样性指数(H_(t))为0.5130,种群间遗传分化系数(G_(st))为0.5307,基因流(N_(m))为0.4388,Mantel检验显示种群间的遗传分化与地理距离无相关性;种群间遗传变异丰度和遗传多样性水平呈现BC>KEL>PS>QM>AQS>KC的递减趋势,聚类分析将6个种群在遗传相似性系数为0.69处分为3类;6个种群内个体间PPL的变化范围为52.11%~81.87%,观测等位基因数(N_(a))和有效等位基因数(N_(e))的变化范围分别为1.5211~1.8187和1.3079~1.4989,H平均为0.2408,I平均为0.3571。结论胀果甘草有较高的遗传多样性水平,但种群间的分化程度较种群内大,遗传多样性更多的存在于种群水平。生境片段化可能是造成其遗传多样性空间分布现状的主要原因,土壤水分含量可能是影响其种群遗传多样性的制约因素。研究结果对全面了解和掌握胀果甘草自然资源现状、物种进化潜力等,制定资源利用与保护的正确策略提供了重要的研究基础。

Objective To evaluate the genetic diversity of Glycyrrhiza inflata,which is one of the source plants of Glycyrrhizae Radix et Rhizoma,abundantly distributed in the Xinjiang.Method ISSR molecular marker method was used to analyze 167 individuals from six populations of G.inflata from different geographical locations of southern Xinjiang.Results In the six populations,46 primers were used to amplify 193 polymorphic bands,accounting for 69.68%of the percentage of polymorphic loci(PPL).Moreover,Nei's genetic diversity index(H)was 0.2722,and Shannon's diversity index(I)was 0.4010.Nei's genetic diversity index at the level of total populations(H_(t))was 0.5130;The genetic differentiation coefficient(G_(st))was 0.5307,showing 0.4388 of the gene flow(N_(m)).In contrast,among these populations,PPLs ranged from 52.11%to 81.87%;the observed allele numbers(N_(a))and the effective allele numbers(N_(e))varied from 1.5211 to 1.8187 and from 1.3079 to 1.4989,respectively;Likewise,the averaged Nei's genetic diversity index(H)was 0.2408,while the averaged Shannon's diversity index(I)was 0.3571.Finally,Mantel test showed that there was no correlation among genetic differentiations and geographical distances.Besides,the level of genetic diversity among populations showed a decreasing tendency of BC>KEL>PS>QM>AQS>KC.In cluster calculation,the six populations were gathered into three groups(clades)at the genetic correlation coefficient of 0.69.The PPL range of six populations was 52.11%-81.87%;The range of Na and Ne was 1.5211-1.8187 and 1.3079-1.4989,the average H value was 0.2408,the average I value was 0.3571.Conclusion It is well known that G.inflata possesses comparatively rich genetic diversity.The genetic diversity of inter-populations was higher than that of intra-populations in this species.Habitat fragmentation was considered as the principle factor giving rise to the spatial distribution pattern of the genetic diversity,and the water content of habitat soils might be the crucial factor impacting the differentiation of the genetic diversity of the species G.inflata.In sum,this study would provide a serviceable reference for a comprehensive and better understanding of the natural resource and their evolutionary potential,contributing to the con servation and sustainable utilization of such unadequately-studied medicinal plants.