Bacillus subtilis is ubiquitously and broadly distributed in various environments but is mostly isolated from soil. Given that B. subtilis is known as a plant growth‐promoting rhizobacterium in agriculture, we aimed to describe the natural distribution of this species and uncover how biotic and abiotic factors affect its distribution. When comparing different soils, we discovered that B. subtilis group species are most abundant in grasslands but can rarely be isolated from forest soil, even if the soil sample sites are situated in proximity. Differential analysis revealed that spore‐forming bacteria exhibited enrichments in the grassland, suggesting niche overlap or synergistic interactions leading to the proliferation of certain Bacillus species in grassland environments. Network analysis further revealed that Bacillus and other Bacillota established a densely interconnected hub module in the grassland, characterised by positive associations indicating co‐occurrence, a pattern not observed in the forest soil. Speculating that this difference was driven by abiotic factors, we combined amplicon sequencing with physico‐chemical analysis of soil samples and found multiple chemical variables, mainly pH, to affect microbial composition. Our study pinpoints the factors that influence B. subtilis abundance in natural soils and, therefore, offers insights for designing B. subtilis‐based biocontrol products in agricultural settings.

中文翻译：

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理清自然土壤中枯草芽孢杆菌群物种丰度的决定因素


枯草芽孢杆菌广泛存在于各种环境中，但大部分是从土壤中分离出来的。鉴于枯草芽孢杆菌被认为是农业中促进植物生长的根际细菌，我们的目的是描述该物种的自然分布，并揭示生物和非生物因素如何影响其分布。在比较不同的土壤时，我们发现枯草芽孢杆菌类物种在草原中最为丰富，但很少能从森林土壤中分离出来，即使土壤采样点距离很近。差异分析显示，孢子形成细菌在草原中表现出富集，表明生态位重叠或协同相互作用导致某些芽孢杆菌物种在草原环境中增殖。网络分析进一步表明，芽孢杆菌和其他芽孢杆菌在草地中建立了一个密集互连的枢纽模块，其特征是正关联表明共现，而这种模式在森林土壤中未观察到。我们推测这种差异是由非生物因素造成的，因此将扩增子测序与土壤样品的理化分析相结合，发现多种化学变量（主要是 pH）会影响微生物组成。我们的研究查明了影响自然土壤中枯草芽孢杆菌丰度的因素，因此为在农业环境中设计基于枯草芽孢杆菌的生物防治产品提供了见解。