目的 开发凉粉草（Platostoma palustre）SSR分子标记，分析其种质资源的遗传多样性，为凉粉草种质资源保护与优良品种选育提供理论支撑。方法 基于凉粉草全基因组序列，挖掘并分析简单重复序列（simple sequence repeats，SSRs）的分布特征，开发多态性SSR引物，为凉粉草遗传多样性评价和群体结构解析提供理论依据。结果 凉粉草基因组中共鉴定出122 699个SSR位点，基因组SSR密度为96.91个/Mb，位点发生频率为10.32 kb/SSR，其中二核苷酸重复基序为优势类型，占总重复基序的68.3%。经过多态性筛选，获得15对多态性较好的SSR引物，其多态性信息指数（polymorphism information content，PIC）介于0.197～0.736，平均值为0.425。对40份凉粉草种质的遗传多样性分析显示，15个SSR位点的等位基因数高于有效等位基因数，等位基因分布呈不均匀分布特征；各位点杂合度存在差异，平均观测杂合度高于平均期望杂合度，二者平均值存在一定差距，表明供试群体偏离了哈迪-温伯格平衡（Hardy-Weinberg equilibrium，HWE），存在遗传变异，整体遗传多样性较好，且群体内部分基因型频率发生改变。固定指数（F）分析结果表明，3个位点的F＞0，12个位点的F＜0，说明种群内杂合个体数量多于纯合个体。香农指数（I）的数值范围为0.449（TDF191）～1.628（TDF166），平均值为0.887。基于UPGMA法，利用Phylip软件构建40份凉粉草种质的系统发育树，可将其划分为2个亚群；通过数字赋值编码，成功构建“0/1”型DNA指纹图谱。结论 获得的大量SSR位点信息，可为凉粉草全基因组SSR标记开发、分子标记辅助育种以及遗传多样性研究提供重要的理论与技术支撑。

Objective This study aimed to develop SSR molecular markers for Platostoma palustre and analyze the genetic diversity of its germplasm resources, so as to provide theoretical support for the conservation of P. palustre germplasm resources and the breeding of elite varieties. Methods Based on the whole-genome sequence of P. palustre, the distribution characteristics of simple sequence repeats (SSRs) were mined and analyzed, and polymorphic SSR primers were developed to provide a theoretical basis for the evaluation of genetic diversity and analysis of population structure in P. palustre. Results A total of 122,699 SSR loci were identified in the P. palustre genome, with a genomic SSR density of 96.91 loci/Mb and a locus occurrence frequency of 10.32 kb/SSR. Dinucleotide repeat motifs were the dominant type, accounting for 68.3% of all repeat motifs. After polymorphism screening, 15 pairs of SSR primers with good polymorphism were obtained. Their polymorphism information content (PIC) ranged from 0.197 to 0.736, with an average value of 0.425. Genetic diversity analysis of 40 P. palustre germplasms showed that the number of alleles at the 15 SSR loci was higher than the number of effective alleles, and the alleles were unevenly distributed. There were differences in heterozygosity among different loci; the average observed heterozygosity was higher than the average expected heterozygosity with a certain gap between them, indicating that the tested population deviated from the Hardy-Weinberg equilibrium (HWE), with genetic variation and favorable overall genetic diversity, and the genotype frequencies of some loci in the population changed. Fixation index (F) analysis showed that F > 0 at 3 loci and F < 0 at 12 loci, indicating that the number of heterozygous individuals was higher than that of homozygous individuals in the population. The Shannon’s information index (I) ranged from 0.449 (TDF191) to 1.628 (TDF166), with an average of 0.887. A phylogenetic tree of the 40 P. palustre germplasms was constructed using Phylip software based on the UPGMA method, which divided the germplasms into two subgroups. A “0/1” DNA fingerprint was successfully constructed by digital assignment coding. Conclusion The abundant SSR loci information obtained in this study can provide important theoretical and technical support for the development of whole-genome SSR markers, molecular marker-assisted breeding, and genetic diversity research of P. palustre.

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广西重点研发计划（桂科AB24010015）；国家自然科学基金资助项目（82460754）；国家自然科学基金资助项目（82260750）；广西药用资源保护与遗传改良重点实验室自主课题（KL2025ZZ05）