微生物类群在叶际微生物群落构建过程中的主导作用

The dominant role of microbial groups in the community assembly process of phyllospheric microorganisms

摘要:

【背景】 叶际微生物群落构建研究对于厘清其多样性的形成和维持机制具有重要意义，但研究进展缓慢。【目的】 探究园林植物叶际微生物群落的构建过程及决定叶际微生物群落构建过程的主要因素。【方法】 在大理苍山国家自然保护区下沿，选择50 m半径范围内的3种园林植物，采集同一朝向的3种不同大小叶片，基于高通量测序技术和群落构建理论模型，分别分析了整体微生物、不同植物种类、不同叶片大小和不同微生物类群的叶际微生物群落构建过程。【结果】 整体叶际微生物群落、不同植物种类和不同大小叶片上的叶际微生物群落构建过程相似，即都由确定性过程的同质选择主导，但细菌和真菌的群落构建存在差异，即叶际真菌与细菌的群落分别由随机性过程的漂变和确定性过程的同质选择主导。通过广义线性模型分析显示，植物种类对叶际微生物的群落构建过程有显著的影响，尤其是微生物类群和微生物类群与植物种类变量组合对叶际微生物群落构建过程有极显著的影响，而叶片大小对叶际微生物群落构建过程有影响但不显著。【结论】 微生物类群是叶际微生物群落构建过程中的主导因素。

Abstract:

[Background] The research on the community assembly of phyllospheric microorganisms is of great significance to clarify the formation and maintenance mechanism of microbial diversity, while it presents slow progress. [Objective] To explore the community assembly processes of phyllospheric microorganisms in garden plants and determine the main influencing factors. [Methods] Three species of garden plants located within a 50-m radius from the lower edge of the Cangshan National Nature Reserve in Dali were selected, and leaves of varying sizes in the same orientation were collected. High-throughput sequencing and the theoretical model of community assembly were employed to analyze the community assembly process of phyllospheric microorganisms on different scales, including the entire microorganism community, different plant species, different leaf sizes, and different microbial groups. [Results] The community assembly processes of all the phyllospheric microorganisms, different plant species, and different leaf sizes were similar. That is, they were all dominated by the homogenous selection of deterministic process. However, there was a distinction in the community assembly processes between bacteria and fungi. Specifically, the community assembly of phyllospheric fungi and phyllospheric bacteria were dominated by the drift of stochastic process and the homogenous selection of deterministic process, respectively. The generalized linear model analysis showed that plant species had a significant impact on the community assembly process of phyllospheric microorganisms. Particularly, the microbial groups and the combination of microbial groups and plant species had highly significant impacts on the community assembly process of phyllospheric microorganisms, while leaf size had an insignificant impact. [Conclusion] Therefore, microbial groups are the decisive factor in the community assembly process of phyllospheric microorganisms.