Environmental Stresses Constrain Soil Microbial Community Functions by Regulating Deterministic Assembly and Niche Width

作者：Xiaojun Wang, Jie Wang, Ji Chen, Т. Martijn Bezemer, Zilin Song, Wolfgang Wanek, Guobin Liu, Chao Zhang · 发表于：Molecular Ecology · 年份：2025 · DOI：10.1111/mec.70096 · 被引用次数：10 · 研究领域：Microbial Community Ecology and Physiology、Gut microbiota and health、Mycorrhizal Fungi and Plant Interactions

Increasing evidence indicates that the loss of soil microbial α-diversity triggered by environmental stress negatively impacts microbial functions; however, the effects of microbial α-diversity on community functions under environmental stress are poorly understood. Here, we investigated the changes in bacterial and fungal α- diversity along gradients of five natural stressors (temperature, precipitation, plant diversity, soil organic C and pH) across 45 grasslands in China and evaluated their connection with microbial functional traits. By quantifying the five environmental stresses into an integrated stress index, we found that the bacterial and fungal α-diversity declined under high environmental stress across three soil layers (0-20 cm, 20-40 cm and 40-60 cm). Metagenomic-based analyses showed that the diversity of functional genes decreased along the stress gradients. High stress enhanced the abundance of genes associated with broad functional categories (e.g., glycolysis/gluconeogenesis, TCA cycle, DNA replication/repair and cell growth/death) but reduced the abundance of genes linked to specialised functional categories (e.g., C, N, S and methane metabolism). Phylogenetic null models and niche analyses indicated that stochastic assembly processes predominated in high-diversity communities, in which bacterial and fungal taxa had a narrow ecological niche. However, in low-diversity communities, deterministic assembly processes were dominant, and taxa had wide niches, cor...