特有珍稀濒危植物景东报春遗传多样性的ISSR分析

景东报春(Primula interjacens Chen)是一分布在中国云南中南部的稀有的、分布区狭窄的特有种.该种含2个变种:原变种景东报春(P.interjacens Chen var.interjacens),现存一个居群;和光叶景东报春(P.interjacens Chen var.epilosa C.M.Hu),有2个居群.本文用ISSR分子标记对景东报春现存的3个居群进行了遗传多样性分析.和我们最初的预计相反,尽管居群小、分布区狭窄,景东报春的遗传多样性却很高(在居群水平的多态位点率P=59.75%,基因多样性HE=0.236 8,Hpop=0.345 9;在种的水平的多态位点率P=75.47%,遗传多样性HT=0.320 5,总的遗传多样性Hsp=0.4618).推测异型花和杂交可能是维持高的遗传多样性的原因.Nei的遗传多样性水平(26.13%)和Shannon多样性指数(25.09%)显示居群间存在中度分化.尽管景东报春原变种和变种在形态上有区别,但用非加权配对算数平均法(UPGMA)聚类分析的结果表明,两者并没有明显的遗传分化,可处理为一个单一的分类单元.基于观察到的居群遗传信息,建议采取就地保护和迁地保护的保护措施.

High Genetic Diversity in a Rare,Narrowly Endemic Primrose Species:Primula interjacens by ISSR Analysis

Primula interjacens Chen (Primulaceae) is a rare and narrow endemic species of central-south of Yunnan Province in China. This species consists of two varieties: P. interjacens var. interjacens known with only one population, and P. interjacens var. epilosa with two populations. Inter-simple sequence repeat (ISSR) marker was used to detect the genetic diversity of the three extant populations. We expected a low genetic diversity level, but our results revealed a high level of intraspecific genetic diversity (at population level: P = 59.75%, H_E = 0.236 8, and H_pop = 0.345 9; at species level: P =75.47%, H_T = 0.320 5, and H_sp = 0.461 8), probably resulting from floral heteromorphism and preferring outcrossing. A moderate level of genetic differentiation among populations was detected based on Nei’s genetic diversity analysis (26.13%) and Shannon’s diversity index (25.09%). Although P. interjacens var. interjacens and P. interjacens var. epilosa were morphologically distinct, UPGMA cluster analysis showed that the two varieties had no distinct genetic differentiation and may be treated as a single taxon. Conservation measures are suggested, including in situ and ex situ strategies, based on the observed population genetic information.