Department of Natural Resources and the Environment, University of New Hampshire, Durham, NH, USA.
Center for Soil Biogeochemistry and Microbial Ecology, University of New Hampshire, Durham, NH, USA.
Nat Commun. 2024 Nov 25;15(1):10209. doi: 10.1038/s41467-024-53947-2.
Soil microbes are a major source of organic residues that accumulate as soil organic matter, the largest terrestrial reservoir of carbon on Earth. As such, there is growing interest in determining the microbial traits that drive soil organic matter formation and stabilization; however, whether certain microbial traits consistently predict soil organic matter accumulation across different functional pools (e.g., total vs. stable soil organic matter) is unresolved. To address these uncertainties, we incubated individual species of fungi in soil organic matter-free model soils, allowing us to directly relate the physiological, morphological, and biochemical traits of fungi to their soil organic matter formation potentials. We find that the formation of different soil organic matter functional pools is associated with distinct fungal traits, and that 'multifunctional' species with intermediate investment across this key grouping of traits (namely, carbon use efficiency, growth rate, turnover rate, and biomass protein and phenol contents) promote soil organic matter formation, functional complexity, and stability. Our results highlight the limitations of categorical trait-based frameworks that describe binary trade-offs between microbial traits, instead emphasizing the importance of synergies among microbial traits for the formation of functionally complex soil organic matter.
土壤微生物是有机残体的主要来源，这些残体积累形成土壤有机质，是地球上最大的陆地碳库。因此，人们越来越关注确定驱动土壤有机质形成和稳定的微生物特征；然而，某些微生物特征是否能够一致地预测不同功能库（例如，总土壤有机质与稳定土壤有机质）中的土壤有机质积累，这一点尚未得到解决。为了解决这些不确定性，我们在无土壤有机质的模型土壤中培养了单个真菌物种，使我们能够将真菌的生理、形态和生化特征与其土壤有机质形成潜力直接相关联。我们发现，不同土壤有机质功能库的形成与不同的真菌特征有关，并且在这个关键的特征分组中具有中间投资的“多功能”物种（即碳利用效率、生长率、周转率以及生物量蛋白质和酚含量）促进了土壤有机质的形成、功能复杂性和稳定性。我们的研究结果强调了基于特征的分类框架的局限性，这些框架描述了微生物特征之间的二元权衡，而不是强调微生物特征之间协同作用对功能复杂的土壤有机质形成的重要性。
