关键词: 甘松, 叶绿体基因组, 群体遗传多样性, 群体遗传结构

Abstract: Nardostachys jatamansi is an important medicinal and aromatic plant distributed across the Qinghai–Tibet Plateau and adjacent regions. Owing to habitat fragmentation, climate change, and overexploitation, it has been classified as Critically Endangered by the IUCN. To elucidate its genetic diversity and population structure, this study examined 14 populations from Qinghai, Sichuan, and Xizang, employing high-throughput sequencing to obtain complete chloroplast genomes. The chloroplast genome of N. jatamansi is 155,541 bp in length and exhibits a typical quadripartite structure, encoding 126 genes. Although relatively conserved, the genome displays detectable nucleotide variation. A total of 940 single nucleotide variants (SNVs) were identified, primarily distributed within the large single-copy (LSC) region. Phylogenetic reconstruction, population structure analysis (STRUCTURE), and principal component analysis (PCA) consistently revealed three well-defined genetic groups with distinct geographic patterns. Haplotype analysis further corroborated this structure, identifying 36 haplotypes. Overall, N. jatamansi exhibits high haplotype diversity (Hd = 0.955) but low nucleotide diversity (π = 0.0014), accompanied by pronounced genetic differentiation among groups (Fst = 0.7713–0.9701). These results provide valuable insights into the genetic diversity and phylogeographic structure of this endangered species and offer a robust scientific basis for its conservation and sustainable utilization.

Key words: Nardostachys jatamansi, chloroplast genome, population genetic diversity, population genetic structure