目的 揭示不同分布区滇龙胆Gentiana rigescens的遗传多样性与遗传结构。方法 基于GBS（genotyping-by- sequencing）简化基因组（reduced-representation genome sequencing，RRGS）技术对采自云南、四川和贵州的19个居群147株滇龙胆进行测序；利用样本SNPs数据集结合聚类树分析、主成分分析、遗传结构分析、Mantel检验等方法，从基因组水平研究滇龙胆居群的遗传多样性与遗传结构；结果 聚类树分析、主成分分析及遗传结构分析显示，不同分布区采集的样品有明显的基因型差异；依据样品地理来源，19个居群大致可分为横断山区（分布于滇西北和川西南的居群）及云贵高原（分布于滇西、滇中、滇东南及贵州的居群）2个亚群。通过观测观测杂合度（observed heterozygosity，Ho）、期望杂合度（expected heterozygosity，He）、多态信息含量（polymorphic information，PIC）、Shannon多样性指数（shannon’s diversity index，I）、Nei’s多样性指数（Nei’s gene diversity，Nei’s）、核苷酸多样性（nucleotide diversity，π）比较，发现云贵高原的居群遗传多样性高于横断山区的居群（云贵高原居群遗传多样性参数均值：Ho＝0.052，He＝0.110，PIC＝0.088，I＝0.164，Nei’s＝0.127，π＝1.677×10⁻³；横断山区居群遗传多样性参数均值：Ho＝0.051，He＝0.098，PIC＝0.077，I＝0.144，Nei’s＝0.114，π＝1.175×10⁻³）；居群遗传分化系数（genetic differentiation index，F_ST）和基因流（gene flow，N_m）分析显示，滇龙胆居群间存在一定的遗传分化和基因流；遗传变异分析（AMOVA）显示滇龙胆种内变异主要来自居群内；基于23个环境变量的环境差异分析显示，横断山亚群与云贵高原亚群生境的热量与UV-B辐射存在差异；Mantel检验显示，居群间的遗传分化主要由环境差异导致，其中UV-B辐射与居群F_ST呈极显著正相关（P＜0.01）。结论 横断山区与云贵高原滇龙胆居群遗传结构和遗传多样性具有差异，分布区UV-B辐射变化可能是驱动滇龙胆居群遗传分化的重要因素。

Objective To uncover the genetic diversity and genetic structure of wild Dianlongdan (Gentiana rigescens Franch. ex Hemsl.) population in different distribution areas. Methods In the study, genomic sequencing of 147 individuals from 19 populations of Yunan, Sichuan and Guizhou was performed by Genotyping-by-sequencing (GBS) simplified genomic technology (reduced-representation genome sequencing, RRGS). SNPs data set combined with cluster analysis, principal component analysis, genetic structure analysis, and mantel test were used to reveal the genetic diversity and genetic structure of wild G. rigescens populations at the whole genome level.Results System clustering, principal component analysis and population genetic structure analysis showed that the samples collected from different distribution areas had obvious genotypic differences. According to the geographical origin of those samples, 19 populations could be roughly divided into two sub-populations. One was the Hengduan Mountains sub-populations (populations distributed in northwest Yunnan and southwest Sichuan), and the other was the Yunnan-Guizhou Plateau sub-populations (populations distributed in western Yunnan, central Yunnan, southeastern Yunnan and Guizhou). It was found that the population genetic diversity in the Yunnan-Guizhou Plateau was higher than that in the Hengduan Mountain area based on the comparison of observed heterozygosity (Ho), expected heterozygosity (He), polymorphic information (PIC), Shannon's diversity index (I), Nei’s gene diversity (Nei’s), and nucleotide diversity (π) at the population level (the Genetic diversity parameters mean value of the Yunnan-Guizhou Plateau populations: Ho = 0.052, He = 0.110, PIC = 0.088, I = 0.164, Nei’s = 0.127, π= 1.677×10^-3; the Genetic diversity parameters mean value of the Hengduan Mountain area populations: Ho = 0.051, He = 0.098, PIC = 0.077, I = 0.144, Nei’s = 0.114, π = 1.175×10^-3). The genetic differentiation index (F_ST) and gene flow (N_m) analysis showed that there were genetic differentiation and gene flows among the populations of G. rigescens. Analysis of molecular variance (AMOVA) showed that intraspecific variation of G. rigescens mainly from within populations. Environmental difference analysis using 23 environmental variables showed various difference between habitats of the Hengduan Mountains sub-populations and the Yunnan-Guizhou Plateau sub-populations with significant difference of thermal indicators and UV-B radiation indicators. Mantel test showed the genetic differentiation of G. rigescens was mainly caused by environmental difference. There was a very significant positive correlation between UV-B radiation and F_ST of populations (P < 0.01). Conclusion Various differences of population genetic diversity and genetic structure could be found between the Hengduan Mountains and Yunnan-Guizhou Plateau sub-populations. And one of the important driving factors for populations genetic differentiation of G. rigescens might be the variation of UV-B radiation in the distribution area.

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国家自然科学基金项目（32060086）；云南省中青年学术和技术带头人后备人才项目（202205AC160088）