Wsp system oppositely modulates antibacterial activity and biofilm formation via FleQ‐FleN complex in Pseudomonas putida. (17th February 2022)

• Record Type: Journal Article
• Authors: Nie, Hailing; Xiao, Yujie; Song, Miaomiao; Wu, Nianqi; Peng, Qi; Duan, Wei; Chen, Wenli; Huang, Qiaoyun
• Is Part Of: Environmental microbiology. Volume 24:Number 3(2022)
• Page Start: 1543
• Page End: 1559
• Publication Date: 2022-02-17
• Subjects: Microbial ecology -- Periodicals; Environmental Microbiology -- Periodicals; 579.17
• DOI: 10.1111/1462-2920.15905
• Languages: English
• ISSNs: 1462-2912

Abstract

Summary: Type VI secretion systems (T6SS) are specific antibacterial weapons employed by diverse bacteria to protect themselves from competitors. Pseudomonas putida KT2440 possesses a functional T6SS (K1‐T6SS) and exhibits antibacterial activity towards a broad range of bacteria. Here we found that the Wsp signal transduction system regulated K1‐T6SS expression via synthesizing the second messenger cyclic di‐GMP (c‐di‐GMP), thus mediating antibacterial activity in P . putida . High‐level c‐di‐GMP produced by Wsp system repressed the transcription of K1‐T6SS genes in structural operon and vgrG1 operon. Transcriptional regulator FleQ and ATPase FleN functioned as repressors in the Wsp system‐modulated K1‐T6SS transcription. However, FleQ and FleN functioned as activators in biofilm formation, and Wsp system promoted biofilm formation largely in a FleQ/FleN‐dependent manner. Furthermore, FleQ‐FleN complex bound directly to the promoter of K1‐T6SS structural operon in vitro, and c‐di‐GMP promoted the binding. Besides, P . putida biofilm cells showed higher c‐di‐GMP levels and lower antibacterial activity than planktonic cells. Overall, our findings reveal a mechanism by which Wsp system oppositely modulates antibacterial activity and biofilm formation via FleQ‐FleN, and demonstrate the relationship between plankton/biofilm lifestyles and antibacterial activity in P . putida .