Quorum-sensing bacteria (QSB) are crucial factors for microbial communication, yet their ecological role in wastewater treatment plants (WWTPs) remains unclear. Here, we developed a method to identify QSB by comparing 16S rRNA gene sequences. QSB in 388 activated sludge samples collected from 130 WWTPs across China primarily were identified as rare taxa and conditionally rare taxa. A co-occurrence network shared by all sludge communities revealed that QSB exhibited higher average clustering coefficient (0.46) than non-QSB (0.15). Individual sludge networks demonstrated that quorum sensing microbiomes were positively correlated with network robustness and network complexity, including average clustering coefficient and link density. We confirmed that QSB keystones and QSB nodes have a positive impact on network complexity by influencing network modularity through a structural equation model. Meanwhile, QSB communities directly contributed to maintaining network robustness (r = 0.29, < 0.05). Hence, QSB play an important role in promoting network complexity and stability. Furthermore, QSB communities were positively associated with the functional composition of activated sludge communities (r = 0.33, < 0.01), especially the denitrification capacity (r = 0.45, < 0.001). Overall, we elucidated the ecological significance of QSB and provided support for QS-based regulation of activated sludge microbial communities.

中文翻译：

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群体感应细菌提高废水处理厂微生物网络的稳定性和复杂性


群体感应细菌（QSB）是微生物通讯的关键因素，但它们在废水处理厂（WWTP）中的生态作用仍不清楚。在这里，我们开发了一种通过比较 16S rRNA 基因序列来识别 QSB 的方法。对全国130个污水处理厂采集的388份活性污泥样品进行QSB鉴定，主要鉴定为稀有类群和条件稀有类群。所有污泥群落共享的共现网络显示，QSB 的平均聚类系数 (0.46) 高于非 QSB (0.15)。单个污泥网络表明，群体感应微生物组与网络稳健性和网络复杂性（包括平均聚类系数和链接密度）呈正相关。我们通过结构方程模型影响网络模块化，证实 QSB 基石和 QSB 节点对网络复杂性产生积极影响。同时，QSB 社区直接为维护网络稳健性做出了贡献（r = 0.29，< 0.05）。因此，QSB 在提高网络复杂性和稳定性方面发挥着重要作用。此外，QSB群落与活性污泥群落的功能组成呈正相关（r = 0.33，< 0.01），特别是反硝化能力（r = 0.45，< 0.001）。总体而言，我们阐明了 QSB 的生态意义，并为基于 QS 的活性污泥微生物群落调节提供支持。