Graduate School of Life Sciences, Tohoku Universitygrid.69566.3a, Sendai, Japan.
Faculty of Science, University of Tokyogrid.26999.3d, Tokyo, Japan.
Microbiol Spectr. 2022 Oct 26;10(5):e0274822. doi: 10.1128/spectrum.02748-22. Epub 2022 Aug 16.
The microbial community is viewed as a network of diverse microorganisms connected by various interspecific interactions. While the stress gradient hypothesis (SGH) predicts that positive interactions are favored in more stressful environments, the prediction has been less explored in complex microbial communities due to the challenges of identifying interactions. Here, by applying a nonlinear time series analysis to the amplicon-based diversity time series data of the soil microbiota cultured under less stressful (30°C) or more stressful (37°C) temperature conditions, we show how the microbial network responds to temperature stress. While the genera that persisted only under the less stressful condition showed fewer positive effects, the genera that appeared only under the more stressful condition received more positive effects, in agreement with SGH. However, temperature difference also induced reconstruction of the community network, leading to an increased proportion of negative interactions at the whole-community level. The anti-SGH pattern can be explained by the stronger competition caused by increased metabolic rate and population densities. By combining amplicon-based diversity survey with recently developed nonlinear analytical tools, we successfully determined the interaction networks of more than 150 natural soil microbial genera under less or more temperature stress and explored the applicability of the stress gradient hypothesis to soil microbiota, shedding new light on the well-known hypothesis.
微生物群落被视为一个由多种微生物通过各种种间相互作用连接而成的网络。虽然应激梯度假说（SGH）预测在更具应激性的环境中，正相互作用更占优势，但由于识别相互作用的挑战，该预测在复杂微生物群落中研究较少。在这里，我们通过将基于扩增子的微生物多样性时间序列数据的非线性时间序列分析应用于在较低应激（30°C）或较高应激（37°C）温度条件下培养的土壤微生物组，展示了微生物网络如何对温度应激做出响应。虽然仅在较低应激条件下持续存在的属表现出较少的正效应，但仅在较高应激条件下出现的属则表现出更多的正效应，这与 SGH 一致。然而，温度差异也诱导了群落网络的重构，导致整个群落水平的负相互作用比例增加。反 SGH 模式可以通过增加的代谢率和种群密度引起的更强竞争来解释。通过将基于扩增子的多样性调查与最近开发的非线性分析工具相结合，我们成功地确定了在较低或较高温度应激下超过 150 个天然土壤微生物属的相互作用网络，并探索了应激梯度假说对土壤微生物组的适用性，为这一著名假说提供了新的见解。
