生物多样性 ›› 2022, Vol. 30 ›› Issue (7): 21508.  DOI: 10.17520/biods.2021508

• 研究报告: 遗传多样性 • 上一篇    下一篇

基于保护基因组学揭示荷叶铁线蕨的濒危机制

孙维悦1,2, 舒江平2,3, 顾钰峰1,4, 莫日根高娃4, 杜夏瑾2, 刘保东1,*(), 严岳鸿2,*()   

  1. 1.哈尔滨师范大学植物生物学黑龙江省高校重点实验室, 哈尔滨 150025
    2.深圳市兰科植物保护研究中心, 广东深圳 518114
    3.中国科学院华南植物园, 广州 510650
    4.中国科学院上海辰山植物科学研究中心, 上海 201602
  • 收稿日期:2021-12-09 接受日期:2022-04-09 出版日期:2022-07-20 发布日期:2022-06-21
  • 通讯作者: 刘保东,严岳鸿
  • 作者简介:99bd@163.com
    *E-mail: yhyan@sibs.ac.cn;
  • 基金资助:
    生态环境部生物多样性调查与评估项目(2019HJ2096001006)

Conservation genomics analysis revealed the endangered mechanism of Adiantum nelumboides

Sun Weiyue1,2, Shu Jiangping2,3, Gu Yufeng1,4, Morigengaowa4, Du Xiajin2, Liu Baodong1,*(), Yan Yuehong2,*()   

  1. 1. Key Laboratory of Plant Biology, College of Heilongjiang Province, Harbin Normal University, Harbin 150025
    2. The Orchid Conservation and Research Centre of Shenzhen, Shenzhen, Guangdong 518114
    3. South China Botanical Garden, Chinese Academy of Sciences, Guangzhou 510650
    4. Shanghai Chenshan Plant Science Research Center, Chinese Academy of Sciences, Shanghai 201602
  • Received:2021-12-09 Accepted:2022-04-09 Online:2022-07-20 Published:2022-06-21
  • Contact: Liu Baodong,Yan Yuehong

摘要:

理解物种的濒危机制对生物多样性的科学保护至关重要。荷叶铁线蕨(Adiantum nelumboides)作为国家一级重点保护野生植物, 其遗传多样性状况和濒危机制一直存在较大争议。本文利用简化基因组测序技术(genotyping by sequencing, GBS)对来自6个居群的28个荷叶铁线蕨样本测序, 共获得29.6 Gb的数据, 并筛选得到9,423个高质量单核苷酸变异位点(SNP), 通过遗传多样性和居群遗传结构分析, 并结合不同气候情景下物种潜在分布区差异, 探讨了荷叶铁线蕨的濒危原因和科学保护策略。结果表明: (1)荷叶铁线蕨具有较低的遗传多样性(Ho = 0.138、He = 0.232、Pi = 0.373), 同时种群间具有较低的遗传分化(Fst = 0.0202)和基因流(Nm = 1.9613); (2)所有样本均来自2个遗传分组, 基因组大小为 5.01‒5.83 Gb, 且均为四倍体, GC含量约为 39%‒41%; (3)生态位模拟表明, 与现代气候相比, 在未来气候变化下荷叶铁线蕨的潜在分布区面积略有增加, 但高适生区面积减小。其主要适生区向北迁移, 影响其分布的主导因子为昼夜温差月均值和最冷季降水量。正是由于荷叶铁线蕨遗传多样性低, 不同种群间遗传分化较低, 再加上气候条件的变化, 其适生区狭窄, 导致其遗传多样性和种群数量急剧下降。因此, 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。建议加强对荷叶铁线蕨的就地保护; 通过生境恢复及自然回归等措施, 增加居群间的基因交流, 防止遗传资源丢失加剧。

关键词: 遗传结构, 物种分布模型, 主导气候因子, 遗传多样性, 简化基因组测序

Abstract

Aims: Understanding the mechanism that leads species to endangerment is crucial to the conservation of biodiversity. Adiantum nelumboides is a key wild plant that is protected at the national level, and its genetic diversity and endangerment mechanism are controversial.
Methods: A total of 28 A. nelumboides samples, from six populations, were used to obtain single-nucleotide variation sites (SNP) by the genotyping by sequencing (GBS) method. The genetic diversity and structure of the population were analyzed and combined with the change in the potential distribution area of species under different climate scenarios. Then the possible causes of endangerment and scientific protection strategies of A. nelumboides were discussed.
Results: The results showed that 29.6 Gb of data was obtained based on the GBS sequencing, and 9,423 high-quality SNP loci were screened. Adiantum nelumboides had low genetic diversity (Ho = 0.138, He = 0.232, Pi = 0.373), low genetic differentiation (Fst = 0.0202) and gene flow (Nm = 1.9613). The A. nelumboides samples are from two ancestral haplotypes, their genome size was 5.01‒5.83 Gb, they were tetraploid, and the GC content was about 39%‒41%. Under future climate change, the potential distribution area of A. nelumboides will increase slightly, in which the area of high fitness is lost. The primary areas that are suitable for the plant are distributed in Wanzhou, Chongqing and further north. The dominant factors affecting its distribution are monthly mean differences in diurnal temperatures and precipitation during the coldest season.
Conclusions: Due to the low genetic diversity, lack of gene exchange between different populations, and changes in climatic conditions, suitable growth areas for A. nelumboides become narrow, resulting in a sharp decline in species diversity and population size. Therefore, their low regeneration ability and excessive disturbance from human activities might be the main reasons for the endangered status of A. nelumboides. It was recommended to strengthen in situ conservation of A. nelumboides. Measures such as habitat restoration and natural regression must be discussed to increase gene exchange across populations. At the same time, a core germplasm of this species must be constructed to prevent the aggravation of genetic resource loss.

Key words: genetic structure, species distribution models, dominant climate factor, genetic diversity, genotyping- by-sequencing