白芨SSR引物筛选及群体遗传多样性研究

白芨(Bletilla striata Rchb.)为中国珍稀濒危植物,重要的药用植物。该研究基于Illumina测序技术构建白芨基因组文库和微卫星文库,设计白芨微卫星引物,用白芨4个野生种群80个个体对引物进行多态性检测,应用4个白芨近缘种中进行引物的通用性检测,并在此基础上分析了白芨的遗传多样性和遗传分化,以探讨白芨的遗传结构和进化潜能。结果表明:(1)白芨基因组中微卫星片断丰富,共检测出17 841条微卫星片断。基于白芨微卫星库对100个位点设计了引物对,经PCR扩增和检测筛选出能够稳定扩增的多态性位点20个,每个位点的复等位基因数(Na)在2~6之间,平均为3.85;20对引物的大部分能够在4个白芨近缘种中成功扩增。(2)白芨在物种水平均有较高的遗传多样性(Na=3.85,I=1.07,H=0.614 7),白芨种群遗传分化强烈(Gst=0.43),居群间的基因流较弱(Nm=0.867 6),居群聚类分析结果均表明地理距离较近的居群具有较近的遗传关系。

Microsatellite Primer Screening and Population Genetic Diversity of Bletilla striata (Thunb.) Rchb. f.

Bletilla striata (Thunb.) Rchb. f. is an endangered plant in China with important medicinal value. In this study, the genomic sequence library and microsatellite library of B. striata was set up based on Illumina sequencing. SSR primers were designed and carried out to test their polymorphism with 80 individuals from 4 wild populations. Four related species of B. striata were used to investigated their cross taxa transferability. In addition, genetic diversity and genetic differentiation of the species were also investigated. The results showed that: (1) Microsatellite sequences were abundance in the genome of B. striata, 17 841 loci were detected in total.100 pair of primers were designed, 20 of them performed high polymorphism after PCR and polyacrylamide gelelectrophoresis, the alleles ranged from 2 to 6 with average of 3.85 per locus. The cross taxa transferability was also examined in 4 related species, most of 20 loci were proved amplifiable in these species. (2) The study revealed that the genetic diversity of B. striata was high (N_a=3.85, I=1.07, H=0.614 7), genetic differentiation was prominent among populations (G_st=0.43). The gene flow among populations was limited (N_m=0.867 6), the adjacent populations performed tight genetic relationship as revealed by cluster analyses of populations. The reasons for genetic construction and conservational strategies of the species were also discussed in this study.