贝克喜盐草微卫星标记的筛选与验证及广西和海南种群遗传多样性分析

Screening and Validation of Microsatellite Markers for Halophila beccarii and Analysis of Genetic Diversity in Guangxi and Hainan Populations

关键词:  贝克喜盐草  微卫星  群体遗传学  引物开发  遗传多样性

Key words:  Halophila beccarii  microsatellite  population genetics  development of primers  genetic diversity

摘要:

贝克喜盐草（Halophila beccarii Asch.）海草床的衰退引起了人们对其保护和管理的重视。关于贝克喜盐草在其生物地理范围内和海草床内的种群遗传研究很少，制约了针对性保护策略的制定。开发微卫星DNA（Microsatellite DNA）标记有助于贝克喜盐草种群生态等方面的研究。基于前期贝克喜盐草单分子实时测序设计的简单重复序列(Simple Sequence Repeat，SSR)引物，本研究随机选择60个位点，合成引物，利用3个种群（广西沙井、海南花场湾及洋浦）24株不同贝克喜盐草个体的基因组DNA通过聚丙烯酰胺凝胶电泳进行筛选，并用筛选出的6对多态性引物进行毛细管电泳，进一步检测并确定引物多态性，对贝克喜盐草3个种群进行了多样性评价。利用GenAlEx和Powermarker软件计算等位基因数、观测杂合度、期望杂合度、多态性信息含量等参数，进行主成分分析（Principal Component Analysis，PCoA），分析种群间遗传变异分化格局。主成分分析表明广西和海南群体之间存在巨大而显著的遗传差异。本研究为贝克喜盐草的遗传研究提供了丰富的分子标记，这些位点将为贝克喜盐草海草床管理及保护提供科学依据。

Abstract:

The decline of Halophila beccarii Asch. seagrass meadows has raised concerns about their protection and management. There is little research on the population genetics of Halophila beccarii within its biogeographical range and seagrass meadows, which hinders the development of targeted conservation strategies. The development of microsatellite DNA markers is helpful for research on the ecology and other aspects of Halophila beccarii populations. Based on the simple sequence repeat (SSR) primers designed by early study of single molecule real-time sequencing of Halophila beccarii, this study randomly selected 60 loci, synthesized primers, and screened using genomic DNA of 24 Halophila beccarii individuals from three populations (Shajing, Huachangwan and Yangpu) through polyacrylamide gel electrophoresis, and used the six polymorphic primers screened for capillary electrophoresis to further detect and determine the polymorphism of primer, and evaluated the diversity of the three Halophila beccarii populations. GenAlEx and Powermarker softwares were used to calculate the number of alleles, observe heterozygosity, expected heterozygosity, polymorphism information content and other parameters, and principal component analysis (PCoA) was used to analyze the differentiation pattern of genetic variation among populations. PCoA indicates significant genetic divergence between populations in Guangxi and Hainan. This study provides abundant molecular markers for the genetic research of Halophila beccarii, which will provide scientific basis for the management and protection of seagrass meadows of Halophila beccarii.