Li Qing, Li Zunfeng, Li Xingxing, Xia Liming, Zhou Xuan, Xu Zhihui, Shao Jiahui, Shen Qirong, Zhang Ruifu
Jiangsu Provincial Key Lab for Organic Solid Waste Utilization, National Engineering Research Center for Organic-based Fertilizers, Jiangsu Collaborative Innovation Center for Solid Organic Waste Resource Utilization, Nanjing Agricultural University, Nanjing, 210095, PR China; Key Laboratory of Microbial Resources Collection and Preservation, Ministry of Agriculture, Institute of Agricultural Resources and Regional Planning, Chinese Academy of Agricultural Sciences, Beijing, 100081, PR China.
Jiangsu Provincial Key Lab for Organic Solid Waste Utilization, National Engineering Research Center for Organic-based Fertilizers, Jiangsu Collaborative Innovation Center for Solid Organic Waste Resource Utilization, Nanjing Agricultural University, Nanjing, 210095, PR China.
Res Microbiol. 2018 Apr;169(3):166-176. doi: 10.1016/j.resmic.2018.01.004. Epub 2018 Feb 8.
Bacillus velezensis strain SQR9 is a well-investigated rhizobacterium with an outstanding ability to colonize roots, enhance plant growth and suppress soil-borne diseases. The recognition that biofilm formation by plant-beneficial bacteria is crucial for their root colonization and function has resulted in increased interest in understanding molecular mechanisms related to biofilm formation. Here, we report that the gene ftsE, encoding the ATP-binding protein of an FtsEX ABC transporter, is required for efficient SQR9 biofilm formation. FtsEX has been reported to regulate the atolysin CwlO. We provided evidence that FtsEX-CwlO was involved in the regulation of SQR9 biofilm formation; however, this effect has little to do with CwlO autolysin activity. We propose that regulation of biofilm formation by CwlO was exerted through the spo0A pathway, since transcription of spo0A cascade genes was altered and their downstream extracellular matrix genes were downregulated in SQR9 ftsE/cwlO deletion mutants. CwlO was also shown to interact physically with KinB/KinD. CwlO may therefore interact with KinB/KinD to interfere with the spo0A pathway. This study revealed that FtsEX-CwlO plays a previously undiscovered regulatory role in biofilm formation by SQR9 that may enhance root colonization and plant-beneficial functions of SQR9 and other beneficial rhizobacteria as well.
贝莱斯芽孢杆菌菌株SQR9是一种经过充分研究的根际细菌，具有出色的定殖于根部、促进植物生长和抑制土传病害的能力。人们认识到植物有益细菌形成生物膜对于其根部定殖和功能至关重要，这导致对理解与生物膜形成相关的分子机制的兴趣增加。在此，我们报告编码FtsEX ABC转运蛋白的ATP结合蛋白的ftsE基因是高效SQR9生物膜形成所必需的。据报道，FtsEX可调节自溶素CwlO。我们提供的证据表明，FtsEX-CwlO参与了SQR9生物膜形成的调控；然而，这种作用与CwlO自溶素活性几乎无关。我们提出，CwlO对生物膜形成的调控是通过spo0A途径实现的，因为在SQR9 ftsE/cwlO缺失突变体中，spo0A级联基因的转录发生了改变，其下游的细胞外基质基因被下调。还发现CwlO与KinB/KinD存在物理相互作用。因此，CwlO可能与KinB/KinD相互作用以干扰spo0A途径。本研究揭示，FtsEX-CwlO在SQR9生物膜形成中发挥了先前未被发现的调控作用，这可能增强SQR9以及其他有益根际细菌的根部定殖和植物有益功能。
