Rawstern Amanda H, Hernandez Damian J, Afkhami Michelle E
Department of Biology, University of Miami, Coral Gables, Florida, USA.
Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, Ontario, Canada.
Ecol Lett. 2025 Jan;28(1):e70031. doi: 10.1111/ele.70031.
Microorganisms underpin numerous ecosystem processes and support biodiversity globally. Yet, we understand surprisingly little about what structures environmental microbiomes, including how to efficiently identify key players. Microbiome network theory predicts that highly connected hubs act as keystones, but this has never been empirically tested in nature. Combining culturing, sequencing, networks and field experiments, we isolated 'central' (highly connected, hub taxa), 'intermediate' (moderately connected), and 'peripheral' (weakly/unconnected) microbes and experimentally evaluated their effects on soil microbiome assembly during early succession in nature. Central early colonisers significantly (1) enhanced biodiversity (35%-40% richer communities), (2) reshaped trajectories of microbiome assembly and (3) increased recruitment of additional influential microbes by > 60%. In contrast, peripheral microbes did not increase diversity and were transient taxa, minimally affected by the presence of other microbes. This work elucidates fundamental principles of network theory in microbial ecology and demonstrates for the first time in nature that central microbes act as keystone taxa.
微生物支撑着众多生态系统过程，并在全球范围内维持生物多样性。然而，令人惊讶的是，我们对塑造环境微生物群落的因素知之甚少，包括如何有效地识别关键参与者。微生物群落网络理论预测，高度连接的枢纽物种起着关键作用，但这从未在自然环境中得到实证检验。通过结合培养、测序、网络分析和野外实验，我们分离出了“核心”（高度连接的枢纽分类群）、“中间”（中度连接）和“边缘”（弱连接/无连接）微生物，并通过实验评估了它们在自然环境早期演替过程中对土壤微生物群落组装的影响。核心早期定殖者显著：（1）增加了生物多样性（群落丰富度提高35%-40%），（2）重塑了微生物群落组装轨迹，（3）使其他有影响力微生物的招募增加了60%以上。相比之下，边缘微生物并没有增加多样性，并且是短暂的分类群，受其他微生物存在的影响最小。这项工作阐明了微生物生态学中网络理论的基本原理，并首次在自然环境中证明核心微生物起着关键分类群的作用。
