RpoN-Dependent Direct Regulation of Quorum Sensing and the Type VI Secretion System in Pseudomonas aeruginosa PAO1

• Published in: Journal of bacteriology 2018-08, Vol.200 (16)
• Main Authors: Shao, Xiaolong, Zhang, Xiaoning, Zhang, Yingchao, Zhu, Miao, Yang, Pan, Yuan, Jian, Xie, Yingpeng, Zhou, Tianhong, Wang, Wei, Chen, Sheng, Liang, Haihua, Deng, Xin
• Format: Article
• Language: English
• Subjects: Bacteriology; Binding sites; Biofilms; Chromatin; Cystic fibrosis; Electrophoretic mobility; Genes; Gram-negative bacteria; Immunoprecipitation; In vivo methods and tests; Motility; Next-generation sequencing; Opportunist infection; Proteolysis; Pseudomonas aeruginosa; Pyocyanin; Reverse transcription; Rhamnolipids; Sequences; Virulence
• ISSN: 0021-9193; 1098-5530
• DOI: 10.1128/JB.00205-18

is a Gram-negative opportunistic pathogen of humans, particularly those with cystic fibrosis. As a global regulator, RpoN controls a group of virulence-related factors and quorum-sensing (QS) genes in To gain further insights into the direct targets of RpoN , the present study focused on identifying the direct targets of RpoN regulation in QS and the type VI secretion system (T6SS). We performed chromatin immunoprecipitation coupled with high-throughput sequencing (ChIP-seq) that identified 1,068 binding sites of RpoN, mostly including metabolic genes, a group of genes in QS ( , , and ) and the T6SS ( and ). The direct targets of RpoN have been verified by electrophoretic mobility shifts assays (EMSA), reporter assay, reverse transcription-quantitative PCR, and phenotypic detection. The ::Tc mutant resulted in the reduced production of pyocyanin, motility, and proteolytic activity. However, the production of rhamnolipids and biofilm formation were higher in the ::Tc mutant than in the wild type. In summary, the results indicated that RpoN had direct and profound effects on QS and the T6SS. As a global regulator, RpoN controls a wide range of biological pathways, including virulence in PAO1. This work shows that RpoN plays critical and global roles in the regulation of bacterial pathogenicity and fitness. ChIP-seq provided a useful database to characterize additional functions and targets of RpoN in the future. The functional characterization of RpoN-mediated regulation will improve the current understanding of the regulatory network of quorum sensing and virulence in and other bacteria.