Influence of cyclic di-GMP metabolism to T3SS expression, biofilm formation and symbiosis efficiency in Mesorhizobium japonicum MAFF303099

• Published in: FEMS microbiology letters Vol. 370
• Main Authors: Escobar, Mariel R, Lepek, Viviana C, Basile, Laura A
• Format: Journal Article
• Language: English
• Published: Oxford Oxford University Press 17.01.2023
• Subjects: Bacteria; Biofilms; Biosynthesis; Efficiency; Enzymes; Mesorhizobium; Metabolism; Motility; Nodulation; Plant roots; Plasmids; Proteins; Swimming; Symbiosis; Tubes; biofilm formation; diguanylate cyclases; rhizobia; type three secretion system; symbiosis; bacterial signaling
• ISSN: 1574-6968; 0378-1097; 1574-6968
• DOI: 10.1093/femsle/fnad087

Abstract A link between the T3SS and inhibition of swimming motility by the transcriptional regulator TtsI in Mesorhizobium japonicum MAFF303099 has been previously reported. Here, we show that mutants in T3SS components display impaired biofilm formation capacity, indicating that a functional T3SS, or at least pili formation, is required for this process. As a first approach to the cdiG regulation network in this bacterium, we started a study of the second messenger cdiG by overexpressing or by deleting some genes encoding cdiG metabolizing enzymes. Overexpression of two putative PDEs as well as deletion of various DGCs led to reduced biofilm formation on glass tubes. Mutation of dgc9509 also affected negatively the nodulation and symbiosis efficiency on Lotus plants, which can be related to the observed reduction in adhesion to plant roots. Results from transcriptional nopX- and ttsI-promoter-lacZ fusions suggested that cdiG negatively regulates T3SS expression in M. japonicum MAFF303099. An approach to M. japonicum MAFF303099 regulation networks by studying the relevance of T3SS in biofilm and the involvement of cdiG in EPS, biofilm, root adherence, symbiosis efficiency and T3SS expression.