College of Life Science and Technology, Huazhong Agricultural University, Wuhan, China.
J Basic Microbiol. 2022 Jan;62(1):35-47. doi: 10.1002/jobm.202100315. Epub 2021 Nov 25.
Microorganisms including Bacillus can produce signal molecules such as surfactin, resulting in the variation of membrane potential to trigger quorum sensing such as biofilm formation and sporulation in response to the environment stresses. However, biosynthesis of surfactin requires multiple resources such as huge enzyme complex, amino acids, fatty acids, and energy. Insufficient resources in the natural soil environment restrain biosynthesis of surfactin. When surfactin is inadequate, cations in soil might serve as substitutes to regulate quorum sensing. Our results showed that both surfactin and cations could lead to the variation of membrane potential, thus providing signals to trigger the quorum sensing such as growth, biofilm formation, and sporulation in Bacillus amyloliquefaciens. Neither KinC nor Abh was essential for surfactin or cations to trigger quorum sensing. The cation signaling pathway is only partially dependent on Spo0A, but the surfactin signaling pathway is fully dependent on this global regulator. Compared to surfactin, cations are less effective in promoting biofilm formation, but more effective to trigger sporulation in B. amyloliquefaciens. This study reveals a pathway through which cations regulate the quorum sensing in B. amyloliquefaciens in the case of insufficient surfactin in environment.
包括芽孢杆菌在内的微生物能够产生信号分子，如表面活性剂，从而导致膜电位变化，以响应环境胁迫触发群体感应，如生物膜形成和孢子形成。然而，表面活性剂的生物合成需要多种资源，如巨大的酶复合物、氨基酸、脂肪酸和能量。在自然土壤环境中，资源不足会抑制表面活性剂的生物合成。当表面活性剂不足时，土壤中的阳离子可能会作为替代品来调节群体感应。我们的结果表明，表面活性剂和阳离子都可以导致膜电位的变化，从而为芽孢杆菌中的群体感应提供信号，如生长、生物膜形成和孢子形成。KinC 和 Abh 对于表面活性剂或阳离子触发群体感应都不是必需的。阳离子信号通路仅部分依赖于 Spo0A，但表面活性剂信号通路完全依赖于这个全局调节因子。与表面活性剂相比，阳离子在促进生物膜形成方面的效果较差，但在触发芽孢杆菌孢子形成方面的效果较好。本研究揭示了在环境中表面活性剂不足的情况下，阳离子通过何种途径调节芽孢杆菌中的群体感应。
