Shifts in Genome Size and Energy Utilization Strategies Sustain Microbial Functions Along an Aridity Gradient

作者：Xiaojun Wang, Wancai Wang, Lei Deng, Ting Li, Shilong Lei, Lu Zhang, Lirong Liao, Zilin Song, Guobin Liu, Chao Zhang · 发表于：Global Change Biology · 年份：2025 · DOI：10.1111/gcb.70498 · 被引用次数：5 · 研究领域：Microbial Community Ecology and Physiology、Polar Research and Ecology、Atmospheric and Environmental Gas Dynamics

ABSTRACT Microbes acquire energy to sustain their survival and function through the decomposition of organic carbon (C) or by oxidizing atmospheric trace gases (e.g., H 2 , CO, CH 4 ). However, how these two microbial energy‐acquisition strategies change along environmental gradients and the underlying mechanisms are unclear. This study investigated the energy strategies and genomic traits of soil microbiomes along a natural aridity gradient, ranging from semi‐humid forests to arid deserts. By analyzing 374 metagenome‐assembled genomes from 13 microbial phyla, we found that the most prevalent microbes are metabolically versatile aerobes that use atmospheric trace gases to support aerobic respiration, C fixation, and N, P, and S cycling. Soil microbes adapt genomic traits associated with reduced energy expenditure in more arid soils, including smaller genome sizes, lower GC content, and fewer 16S rRNA gene copies. Microbial communities in diverse arid habitats are capable of utilizing organic compounds and the oxidation of trace gases (e.g., H 2 , CO, CH 4 , and H 2 S) as energy sources. However, the utilization of organic energy decreased while reliance on trace gas oxidation increased with increasing aridity. Higher consumption rates of H 2 , CO, and CH 4 in desert soils from ex situ culture experiments confirmed that increased aridity stimulates microbial oxidation of atmospheric trace gases. This shift in energy utilization was strongly correlated with declining soil organ...