生物多样性 ›› 2023, Vol. 31 ›› Issue (2): 22492.  DOI: 10.17520/biods.2022492

所属专题: 土壤生物与土壤健康

• 研究报告: 微生物多样性 • 上一篇    下一篇

降水对古尔班通古特沙漠细菌群落多样性和构建过程的影响

杜芳1,2, 荣晓莹1,*(), 徐鹏1,2, 尹本丰1, 张元明1   

  1. 1.中国科学院新疆生态与地理研究所荒漠与绿洲生态国家重点实验室, 乌鲁木齐 830011
    2.中国科学院大学, 北京 100049
  • 收稿日期:2022-08-25 接受日期:2022-10-18 出版日期:2023-02-20 发布日期:2022-12-30
  • 通讯作者: *荣晓莹, E-mail: rongxy@ms.xjb.ac.cn
  • 基金资助:
    新疆维吾尔自治区自然科学基金重点项目(2022D01D83);“西部青年学者”项目(2019-XBQNXZ-B-007);国家自然科学基金-新疆联合基金重点项目(U2003014);国家自然科学基金(31670007);新疆第三次科学考察项目子课题(2021xjkk0505)

Bacterial diversity and community assembly responses to precipitation in the Gurbantunggut Desert

Fang Du1,2, Xiaoying Rong1,*(), Peng Xu1,2, Benfeng Yin1, Yuanming Zhang1   

  1. 1. State Key Laboratory of Desert and Oasis Ecology, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Urumqi 830011
    2. University of Chinese Academy of Sciences, Beijing 100049
  • Received:2022-08-25 Accepted:2022-10-18 Online:2023-02-20 Published:2022-12-30
  • Contact: *Xiaoying Rong, E-mail: rongxy@ms.xjb.ac.cn

摘要:

明确荒漠降水对细菌群落多样性和群落构建过程的影响, 有助于进一步认识荒漠土壤细菌群落结构和功能对降水变化的响应及反馈机制。基于古尔班通古特沙漠区域降水梯度上的土壤细菌群落高通量测序数据, 比较分析了降水差异对总细菌、高丰度及低丰度细菌类群多样性和群落组成的影响, 使用零模型(null model)方法分析确定性过程和随机性过程对细菌群落构建的相对重要性。结果表明: 绿弯菌门是高丰度与低丰度细菌类群优势细菌门。沿降水梯度总细菌和高丰度细菌类群的丰富度及Shannon多样性指数无显著差异, 随降水减少, 低丰度细菌类群的丰富度和Shannon多样性显著降低(P < 0.05); 降水差异显著影响不同丰度细菌类群的群落组成, 且沿降水梯度, 低丰度细菌的群落变异与物种空间周转大于高丰度与总细菌类群, 表明荒漠不同丰度细菌类群差异响应区域小范围降水梯度, 低丰度细菌类群对区域降水变化具有强敏感性, 而总细菌和高丰度细菌类群对降水变化具有较强的抵抗力; 零模型分析显示, 扩散限制主导古尔班通古特沙漠不同降水样点细菌的群落构建过程, 而荒漠低丰度细菌类群同时还受到强的异质选择作用(43.0%), 表明荒漠降水差异增强了低丰度细菌的环境选择作用或者生物间的竞争作用。另外, 空间地理距离决定了不同降水梯度总细菌群落的构建过程, 而年均降水量对平衡低丰度细菌类群的确定性过程与随机性过程的相对重要性具有重要作用。综上所述, 古尔班通古特沙漠小尺度的降水差异显著改变了荒漠表层土壤的细菌群落组成, 低丰度细菌敏感响应小尺度范围的降水差异, 有助于减缓荒漠细菌对环境变化响应的滞后性; 扩散限制对总细菌和高丰度细菌β多样性的决定作用比对低丰度细菌强, 显示空间地理距离对荒漠总细菌和高丰度细菌的物种周转解释率高于低丰度细菌, 而荒漠低丰度细菌的多样性分布和生态位偏好除受到空间地理尺度的影响外, 还具有更强的降水依赖性。

关键词: 温带荒漠, 年均降水量, 高丰度细菌, 低丰度细菌, 群落构建

Abstract

Aims: (1) To study effects of mean annual precipitation (MAP) on the diversity and community assembly of bacterial communities in the Gurbantunggut Desert; (2) Further our understanding of how bacterial communities respond to desertification.

Methods: We conducted the high-throughput sequencing data of bacterial communities from 30 soil samples (0-10 cm depth) collected from the Gurbantunggut Desert, where the MAP ranges from180 mm to 230 mm. We investigated the effect of MAP on the diversity of three defined categories of bacterial communities (whole, abundant and rare), and compared the compositions of the bacterial communities. Finally, we assessed the relative importance of deterministic and stochastic processes of the bacterial community assembly using the null model method.

Results: The results showed that MAP had no significant influence on the richness and Shannon index of whole and abundant bacterial taxa (P > 0.05). However, the indices of richness and Shannon diversity of rare bacterial taxa were significantly decreased with MAP reduction (P < 0.05). Moreover, MAP had a noticeable effect on the community composition of the whole, abundant and rare bacterial communities, with the rare bacterial taxa having the highest levels of community variation and spatial turnover followed by whole and abundant bacterial communities, respectively. The results indicated that the whole, abundant, and rare bacterial taxa in the Gurbantunggut Desert responded differently to MAP. Rare bacterial taxa showed strong sensitivity to regional precipitation differences, whereas whole and abundant bacterial taxa were resistant to MAP variation. The null model analysis showed that dispersal limitation dominated the bacterial community assembly process in the Gurbantunggut Desert (> 73.0%). In contrast, the rare desert bacterial taxa were subject to heterogeneous selection (43.0%), indicating that the desert precipitation differences enhanced the environmental selection or species competition of the rare bacterial taxa. In addition, spatial distance and MAP determined the whole bacterial community construction, and the abundant and rare taxa respectively. Particularly, MAP played an essential role in balancing the relative importance between deterministic and stochastic processes of the rare bacterial taxa.

Conclusion: Small-scale MAP differences in the Gurbantunggut Desert significantly alter the composition and assembly processes of the bacterial community. The community composition and turnover of rare bacterial taxa were affected strongly by MAP, which help mitigate the lag in the response of desert bacteria to environmental changes. Dispersal limitation isa stronger determinant of β diversity for whole and abundant bacterial taxa than for rare bacterial taxa, indicating that geographic distance explained more species turnover for desert whole and abundant bacterial taxa than for rare bacterial taxa, while the diversity distribution and ecological niche preference of desert rare bacteria were more precipitation-dependent than spatial geographic scale.

Key words: temperate desert, mean annual precipitation, abundant bacterial taxa, rare bacterial taxa, community assembly