极小种群野生植物海南风吹楠的遗传多样性研究

Genetic Diversity of Horsfieldia hainanensis: An Endangered Species with Extremely Small Populations

摘要:

为探讨海南风吹楠（Horsfieldia hainanensis）的濒危原因，利用限制性酶切位点相关的DNA测序技术（RAD-seq）开发单核苷酸多态性（SNPs），评估居群的遗传多样性和遗传结构。结果表明，海南风吹楠的遗传多样性较低（Ho=0.167），其中BWL居群表现出最高的遗传多样性；居群间存在中等程度的遗传分化（F_st=0.120）。Structure分析表明居群的最佳聚类值为2，但个别居群的遗传结构混杂，Mantel检测结果也表明遗传距离和地理距离没有相关性（r=0.733，P<0.075）。自身更新能力低以及过度的人为活动干扰，可能是导致其濒危的主要原因。建议加强对遗传多样性高的居群（BWL和YGL）进行就地保护；对生境破坏严重的居群（EXL和DLS）进行近地或迁地保护，以增加居群间的基因交流，同时构建核心种质，防止遗传资源丢失加剧。

Abstract:

In order to explore the causes of the endangered species Horsfieldia hainanensis, the genetic diversity and population structure were analyzed by using restriction-site associated DNA sequencing (RAD-seq) for developing single nucleotide polymorphisms (SNPs). The results showed that the genetic diversity of H. hainanensis was low (Ho=0.167) and the genetic differentiation between populations was significant (F_st=0.120). Structure analysis showed that the optimal clustering value of the population was 2, but the genetic structure of some populations was mixed, which was consistent with the results of Mantel correlation test showing no correlation between genetic distance and geographic distance (r=0.733, P<0.075). Therefore, low regeneration ability and excessive disturbance of human activities might be the main reason for endangered status of H. hainanensis. It was recommended to strengthen in situ conservation of populations with high genetic diversity, such as BWL and YGL, and strengthen near-situ or ex-situ conservation of populations with severe habitat damage, such as EXL and DLS, to increase gene exchange among populations. At the same time construct the core germplasm of this species to prevent the aggravation of genetic resource loss.