High temperatures enhance the microbial genetic potential to recycle C and N from necromass in high‐mountain soils

作者：Jonathan Donhauser, Weihong Qi, Benoît Bergk-Pinto, Beat Frey · 发表于：Global Change Biology · 年份：2020 · DOI：10.1111/gcb.15492 · 被引用次数：136 · 研究领域：Microbial Community Ecology and Physiology、Genomics and Phylogenetic Studies、Soil Carbon and Nitrogen Dynamics

Climate change is strongly affecting high-mountain soils and warming in particular is associated with pronounced changes in microbe-mediated C and N cycling, affecting plant-soil interactions and greenhouse gas balances and therefore feedbacks to global warming. We used shotgun metagenomics to assess changes in microbial community structures, as well as changes in microbial C- and N-cycling potential and stress response genes and we linked these data with changes in soil C and N pools and temperature-dependent measurements of bacterial growth rates. We did so by incubating high-elevation soil from the Swiss Alps at 4°C, 15°C, 25°C, or 35°C for 1 month. We found no shift with increasing temperature in the C-substrate-degrader community towards taxa more capable of degrading recalcitrant organic matter. Conversely, at 35°C, we found an increase in genes associated with the degradation and modification of microbial cell walls, together with high bacterial growth rates. Together, these findings suggest that the rapidly growing high-temperature community is fueled by necromass from heat-sensitive taxa. This interpretation was further supported by a shift in the microbial N-cycling potential towards N mineralization and assimilation under higher temperatures, along with reduced potential for conversions among inorganic N forms. Microbial stress-response genes reacted inconsistently to increasing temperature, suggesting that the high-temperature community was not severely stressed b...