广西药用植物两面针遗传多样性的ISSR分析

ISSR Analysis on Genetic Diversity of Medically Important Zanthoxylum nitidum (Roxb.) DC.in Guangxi

关键词:  药用植物  两面针  遗传多样性  ISSR

Key words:  medicinal plants  Zanthoxylum nitidum  genetic diversity  ISSR

摘要:

[目的]目前两面针(Zanthoxylum nitidum)野生资源逐渐减少,开展对其居群遗传学研究有利于两面针野生资源的保护和可持续利用。[方法]利用ISSR分子标记对11个广西两面针自然居群共138个样本进行DNA多态性分析。[结果]从100个随机引物中筛选出8个有效引物,共扩增出63个DNA片段,都为多态性条带,多态位点百分率(P)为100%。两面针在物种水平上具有较高遗传多样性,Nei's基因多样性(He)和Shannon信息指数(I)分别为0.227和0.356。两面针11个居群的遗传分化系数(Gst)为0.490,居群内变异占51%,居群间变异占49%,说明居群间和居群内的遗传分化基本持平;居群间基因流(Nm)为0.52,表明居群间基因流动较贫乏。各居群间的遗传距离在0.053~0.334之间,居群间的聚类及Mantel检验(r=0.391,p=0.040)均表明广西两面针居群地理距离与遗传距离之间的相关性不明显。[结论]广西野生两面针种质资源多样性较高,有利于培育高品质的药材品种;就地保护是两面针资源保护的首选,选择个体数量多、居群内变异系数大,自然环境不易受到人为影响的天然居群进行保护。

Abstract:

[Objective] Zanthoxylum nitidum (Rutaceae) is an important medicinal plant mainly distributed in southern China.In recent years, however, the distribution range of this species has been reduced greatly due to human over exploitation and deterioration of its habitat.Studying the population genetics of this species is essential for the conservation and sustainable utilization of the plant germplasm resource.[Methods] In this study, we used eight ISSR markers to measure genetic diversity of 138 individuals from eleven populations of Z.nitidum in Guangxi.[Results] A total of 63 DNA fragments were scored, and the percentage of polymorphic bands (P) was 100%.High level of genetic diversity was detected in Z.nitidum (He=0.227;I=0.356).AMOVA analysis indicated that coefficient of genetic differentiation (Gst) was 0.490 (51% of the total genetic variation resided within a population and 49% between populations), which demonstrated that the genetic variation between populations and within a population was roughly equal.Gene flow (Nm) between each population was 0.52, which showed a relatively lacking gene flowing.The genetic distance between each population ranged 0.053~0.334.The results of Mantel test (r=0.391, p=0.040) and UPGMA cluster indicated that there was no significant relationship between geographical distance and genetic distance.[Conclusion] This investigation indicats that the genetic diversity of Z.nitidum in Guangxi is high, which is good for the cultivation of high quality herbmedicine;In situ conservation is advocated first, and keeping a stable environment for this herb is necessary.