基于ISSR标记的麻花艽遗传多样性分析

目的探讨秦艽基原植物之一麻花艽Gentiana straminea的遗传多样性,并构建DNA指纹谱。方法在其自然分布区广泛取样,共涉及西藏、青海、甘肃及四川等地28个居群83份样本,应用ISSR分子标记技术,POPGEN软件分析遗传信息参数,NTSYS软件构建亲缘关系UPGMA聚类图。结果从100条引物中筛出7条多态性好、条带清晰的引物用于ISSR分析。共检测到95个条带,其中多态性条带88个,多态性条带百分率(PPL)为92.63%;麻花艽居群间的期望杂合度(H_e)为0.288 2,多样性信息指数(I_m)为0.437 1,种群间基因分化系数(G_(st))为0.678 3,基因流(N_m)为0.237 1,遗传距离为0.074 3~0.490 0。UPGMA树将麻花艽居群主要分为2大支。结论麻花艽种群遗传多样性水平较高,居群间遗传多样性水平高于居群内;其遗传变异主要存在于居群间;遗传特性与地理分布具有一定相关性。该工作可为麻花艽品种鉴定、物种就地保护、探讨环境等因素对于遗传分化的影响及药材道地性研究提供基础资料。

Assessment of genetic diversity on Gentiana straminea based on ISSR markers

Objective To assess the genetic diversity of Gentiana straminea (Gentianaceae). Methods Intersimple sequence repeat (ISSR) markers were used. Twenty-eight populations (83 individuals) of G. straminea were sampled from Sichuan, Qinghai, Gansu provinces, and Autonomous Region of Tibet. ISSR data were analyzed with the program POPGEN, and a UPGMA dendrogram was constructed. Results PCR products corresponding to 183 alleles at 95 loci, amplified by the seven primers were scored. Eighty-eight loci were polymorphic. Expected heterozygosity (H_e) and Shannon''s information index (I_m) were 0.288 2 and 0.437 1, respectively. Nei''s coefficient of genetic differentiation (G_st) and gene flow (N_m) were 0.678 3 and 0.237 1 at the population level, respectively. The genetic distance varied from 0.074 3 to 0.490 0. G. straminea populations were mainly divided into two braches by UPGMA tree. Conclusion Genetic diversity level of G. straminea is high, and genetic diversity level among populations of G. straminea is higher than that in one population; Its autogenous variation mainly exist among populations; Hereditary capacity has certain correlation with geographical distribution. This work contributes basic information for variety identification, species in situ conservation, and enviroment investigation on the influence of heredity differentiated and Chinese Materia Medica genuine study. The congruence between genetic distance and geographic distances is high.