广西极小种群野生喙核桃遗传多样性分析

Genetic Diversity Analysis of Annamocarya sinensis, a Wild Plant with Extremely Small Populations in Guangxi

摘要:

喙核桃(Annamocarya sinensis)为国家二级重点保护野生植物和极小种群野生植物。阐明广西喙核桃野生种群遗传多样性和遗传变异，可为广西喙核桃遗传多样性保护及管理策略制定提供指导。该研究筛选出6对稳定性和多态性良好的SSR引物，对广西4个喙核桃野生种群(共47个个体)的遗传多样性和遗传变异进行了分析。结果表明，4个喙核桃野生种群的观测等位基因数平均为2.125，有效等位基因数平均为1.581，Shannon信息指数平均为0.477，观测杂合度平均为0.310，期望杂合度平均为0.286，等位基因丰富度平均为1.677，广西喙核桃的遗传多样性水平较低。群体间遗传呈中度分化(0.120)，种群间遗传变异占20%，种群内遗传变异占80%。Structure和UPGMA分析表明，47份样品大致分为3类，样品间彼此相互混杂，遗传背景丰富。桂林市永福县种群的群体遗传多样性最高(He=0.339，I=0.598)，应把该种群作为重点保护单元。

Abstract:

Annamocarya sinensis is a national Class Ⅱ key protected wild plant with extremely small populations.To elucidate the genetic diversity and variation of wild A. sinensis population in Guangxi can provide guidance for the development of genetic diversity conservation and management strategies. The genetic diversity and genetic variation of 4 wild populations (47 individuals) in Guangxi were analyzed by using 6 pairs of SSR primers with good stability and polymorphism. The results showed that the average number of observed alleles was 2.125, the average number of effective alleles was 1.581, the average Shannon information index was 0.477, the average observed heterozygosity was 0.310, the average expected heterozygosity was 0.286, and the average allele richness was 1.677. The level of genetic diversity of A. sinensis in Guangxi was low. There was a moderate genetic differentiation among populations (0.120), accounting for 20% among populations and 80% within population. Structure and UPGMA analysis showed that the 47 samples could be divided into three categories, which were mixed with each other and had rich genetic background. The genetic diversity of Yongfu County population in Guilin City was the highest (He=0.339, I=0.598), which should be regarded as the key conservation unit.