Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China; University of the Chinese Academy of Sciences, Beijing 100049, China.
Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China.
Sci Total Environ. 2020 Aug 15;730:139116. doi: 10.1016/j.scitotenv.2020.139116. Epub 2020 May 4.
Bacteria are critical ecosystem drivers in both aquatic and terrestrial ecosystems. However, our understanding of the mechanisms generating and maintaining biodiversity on large spatial scales remains limited, especially mechanisms involving rare taxa in soil ecosystems. In the present study we took paddy soils in China as model ecosystems and studied the ecological diversity and assembly mechanisms of both the rare and abundant bacterial subcommunities. We collected 339 paddy soil samples from 113 sites across 19 Chinese provinces that span distances of up to 3869 km. The bacterial community was characterized by high-throughput sequencing of the 16S rRNA gene. The α-diversity of rare and abundant subcommunities showed opposite quadratic correlations with the key environmental factor soil pH. Rare taxa exhibited a stronger distance-decay relationship than the abundant subcommunity. Moreover, deterministic selection processes dominated in the assembly of the abundant subcommunity while stochastic processes dominated in that of the rare subcommunity based on both variation partitioning analysis and the phylogenetic null model. Soil pH was also the main deterministic factor driving the geographical distributions of both the rare and abundant subcommunity. Besides, mean annul temperature and soil texture were also found to be important factors affecting the biogeography and diversity patterns of abundant and rare subcommunities. These results indicate that the mechanisms generating and maintaining the diversity of the abundant and rare subcommunities were totally different in paddy soils, suggesting that these two subcommunities may respond differently to future environmental change.
细菌是水生和陆地生态系统中至关重要的生态系统驱动因素。然而，我们对于在大空间尺度上产生和维持生物多样性的机制的理解仍然有限，特别是涉及土壤生态系统中稀有分类群的机制。在本研究中，我们以中国稻田土壤为模型生态系统，研究了稀有和丰富细菌亚群的生态多样性和组装机制。我们从中国 19 个省份的 113 个地点收集了 339 个稻田土壤样本，这些地点之间的距离长达 3869 公里。通过高通量测序 16S rRNA 基因对细菌群落进行了特征描述。稀有和丰富亚群的 α 多样性与关键环境因子土壤 pH 呈相反的二次相关关系。稀有分类群的距离衰减关系强于丰富亚群。此外，基于变异划分分析和系统发育零模型，确定性选择过程主导了丰富亚群的组装，而随机过程主导了稀有亚群的组装。土壤 pH 也是驱动稀有和丰富亚群地理分布的主要确定性因素。此外，年平均温度和土壤质地也被发现是影响丰富和稀有亚群生物地理学和多样性模式的重要因素。这些结果表明，在稻田土壤中，丰富和稀有亚群的多样性产生和维持机制完全不同，这表明这两个亚群可能对未来的环境变化有不同的反应。
