Microbial communities play important roles in all ecosystems and yet a comprehensive understanding of the ecological processes governing the assembly of these communities is missing. To address the role of biotic interactions between microorganisms in assembly and for functioning of the soil microbiota, we used a top-down manipulation approach based on the removal of various populations in a natural soil microbial community. We hypothesized that removal of certain microbial groups will strongly affect the relative fitness of many others, therefore unraveling the contribution of biotic interactions in shaping the soil microbiome. Here we show that 39% of the dominant bacterial taxa across treatments were subjected to competitive interactions during soil recolonization, highlighting the importance of biotic interactions in the assembly of microbial communities in soil. Moreover, our approach allowed the identification of microbial community assembly rule as exemplified by the competitive exclusion between members of Bacillales and Proteobacteriales. Modified biotic interactions resulted in greater changes in activities related to N- than to C-cycling. Our approach can provide a new and promising avenue to study microbial interactions in complex ecosystems as well as the links between microbial community composition and ecosystem function.

微生物群落在所有生态系统中都发挥着重要作用，但缺乏对控制这些群落组装的生态过程的全面了解。为了解决微生物在组装和土壤微生物群功能中的生物相互作用的作用，我们使用了一种自上而下的操作方法，该方法基于去除天然土壤微生物群落中的各种种群。我们假设去除某些微生物群会强烈影响许多其他微生物群的相对适应性，因此揭示了生物相互作用在塑造土壤微生物群中的贡献。在这里，我们表明，39% 的主要细菌分类群在土壤重新定殖过程中受到竞争性相互作用的影响，强调生物相互作用在土壤中微生物群落组装中的重要性。此外，我们的方法允许识别微生物群落组装规则，例如芽孢杆菌目和变形杆菌目成员之间的竞争排斥。改良的生物相互作用导致与 N- 循环相关的活动发生的变化比 C-循环更大。我们的方法可以为研究复杂生态系统中的微生物相互作用以及微生物群落组成与生态系统功能之间的联系提供一条新的、有前景的途径。改良的生物相互作用导致与 N- 循环相关的活动发生的变化比 C-循环更大。我们的方法可以为研究复杂生态系统中的微生物相互作用以及微生物群落组成与生态系统功能之间的联系提供一条新的、有前景的途径。改良的生物相互作用导致与 N- 循环相关的活动发生的变化比 C-循环更大。我们的方法可以为研究复杂生态系统中的微生物相互作用以及微生物群落组成与生态系统功能之间的联系提供一条新的、有前景的途径。