Microbial taxa within complex ecological networks can be classified by their universal roles based on their level of connectivity with other taxa. Highly connected taxa within an ecological network (kinless hubs) are theoretically expected to support higher levels of ecosystem functions than less connected taxa (peripherals). Empirical evidence of the role of kinless hubs in regulating the functional potential of soil microbial communities, however, is largely unexplored and poorly understood in agricultural ecosystems. Here, we built a correlation network of fungal and bacterial taxa using a large-scale survey consisting of 243 soil samples across functionally and economically important agricultural ecosystems (wheat and maize); and found that the relative abundance of taxa classified as kinless hubs within the ecological network are positively and significantly correlated with the abundance of functional genes including genes for C fixation, C degradation, C methanol, N cycling, P cycling and S cycling. Structural equation modeling of multiple soil properties further indicated that kinless hubs, but not provincial, connector or peripheral taxa, had direct significant and positive relationships with the abundance of multiple functional genes. Our findings provide novel evidence that the relative abundance of soil taxa classified as kinless hubs within microbial networks are associated with high functional potential, with implications for understanding and managing (through manipulating microbial key species) agricultural ecosystems at a large spatial scale.

复杂生态网络中的微生物分类单元可以根据其与其他分类单元的连通性级别，通过其通用角色进行分类。从理论上讲，与较少连接的分类单元（外围设备）相比，生态网络中的高度连接的分类单元（无枢纽集线器）可以支持更高级别的生态系统功能。但是，在农业生态系统中，关于无纽带枢纽在调节土壤微生物群落功能潜能中作用的经验证据在很大程度上尚未得到探索和了解。在这里，我们使用大规模调查建立了真菌和细菌类群的相关网络，该调查由功能和经济上重要的农业生态系统（小麦和玉米）的243个土壤样本组成；并且发现在生态网络内被分类为无纽带枢纽的分类单元的相对丰度与功能基因的丰度正相关，并且这些功能基因包括C固定，C降解，C甲醇，N循环，P循环和S循环的基因。多种土壤特性的结构方程模型进一步表明，无纽带集线器与多种功能基因的丰富度有着直接的显着正相关关系，而没有省级的，连接的或外围的分类单元。我们的发现提供了新的证据，即微生物网络内被归类为无纽带枢纽的土壤分类单元的相对丰度与较高的功能潜力相关联，对于在较大的空间规模上理解和管理（通过操纵微生物关键物种）农业生态系统具有启示意义。