土壤多功能性对微生物多样性降低的响应

土壤微生物群落在驱动多种生态系统功能和生态过程中发挥着重要作用，是维持生物地球化学循环的主要驱动力.鉴于全球背景下观察到土壤微生物多样性随着土地利用集约化、气候变化而降低的现象，对土壤微生物多样性的减少是否会对土壤多功能性产生影响进行调查显得尤为重要.利用稀释灭绝法构建土壤微生物多样性梯度，结合高通量测序等技术手段，探究细菌、真菌和原生生物多样性降低对土壤多功能性的影响.结果表明，与未灭菌土壤相比，稀释处理土壤微生物α多样性（丰富度指数和香农指数）显著降低.主坐标分析（PCoA）表明，未灭菌土壤微生物群落结构与稀释处理土壤存在显著分异，而且细菌和真菌群落对稀释处理的响应高于原生生物.回归模型显示，土壤多功能性与微生物多样性指标呈显著的负线性关系，表明土壤微生物群落变化是调节土壤多功能性的关键因素.其次，通过集成推进树（ABT）和回归模型预测分析发现，一些特定的微生物类群如真菌短柄菌属（Solicoccozyma）、瓦湖胶珊瑚菌（Holtermanniella）和细菌属Rudaea相对丰度与土壤多功能性显著负相关，说明关键微生物类群在生物过程中发挥了指示性作用.进一步通过结构方程模型揭示，细菌、真菌和原生生物多样性都对土壤多功能性存在直接或间接影响，其中细菌是驱动土壤多功能性变化的关键生物因子.研究为土壤微生物多样性对土壤多功能性的影响提供了试验证据，并认为在单一农业生态系统中维持一定的土壤微生物群落多样性，特别是关键微生物类群的多样性对未来生态系统功能的可持续发展具有重要意义.

Response of Soil Multifunctionality to Reduced Microbial Diversity

Soil microbial communities play an important role in driving a variety of ecosystem functions and ecological processes and are the primary driving force in maintaining the biogeochemical cycle. It has been observed that soil microbial diversity decreases with land use intensification and climate change in the global background. It is essential to investigate whether the reduction in soil microbial diversity can affect soil multifunctionality. Thus, in this study, the dilution-to-extinction method was used to construct the gradient of soil microbial diversity, combined with high-throughput sequencing to explore the impact of the reduction in bacterial, fungal, and protist diversity on soil multifunctionality. The results showed that the soil microbial alpha diversity (richness and Shannon index) was significantly lower than that of the original soil. Principal coordinate analysis (PCoA) showed that the microbial community structure of original soil was significantly different from that of diluted soil, and the response of bacterial and fungal communities to diluted soil was higher than that of protists. The regression model showed that there was a significant negative linear relationship between the average response value of soil multi-function and the index of microbial diversity, indicating that the change in soil microbial community was the key factor in regulating soil multifunctionality. The regression model showed that there was a significant negative linear relationship between soil multifunctionality and microbial diversity, indicating that the change in soil microbial community was the key factor to regulate soil multi-kinetic energy. Through the aggregated boosted tree analysis (ABT) and regression model, we found that some specific microbial groups, such as the Solacocozyma and Holtermaniella of fungi and Rudaea of bacteria, could significantly promote the change in soil multifunctionality, which showed that key microbial taxa play an indicative role in biological processes. Furthermore, the structural equation model revealed that bacteria could affect soil multifunctionality through the interaction between microbiomes, which was the key biological factor driving the change in soil multifunctionality. This study provided experimental evidence for the impact of soil microbial diversity on soil multifunctionality, and promoted the notion that maintaining a certain diversity of soil microbial community in a single agricultural ecosystem, especially the diversity of key microbial taxa, is of great significance to the sustainable development of ecosystem function in the future.