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Updated: May 21, 2026

Synthesis and Assay of Vibrio Quorum Sensing Inhibitors
Published on: May 31, 2024
Evidence that the Vibrio vulnificus flagellar regulator FlhF is regulated by a quorum sensing master regulator SmcR
Seung Min Kim1, Dong Hwan Lee1, Sang Ho Choi1
1National Research Laboratory of Molecular Microbiology and Toxicology, Department of Agricultural Biotechnology, and Center for Food Safety and Toxicology, Seoul National University, Seoul 151-921, Republic of Korea.
Abstract:
A single polar flagellum and motility are potential virulence factors of Vibrio vulnificus, a foodborne pathogen. In the present study, the functions of FlhF and regulatory characteristics of the flhF expression of V. vulnificus were investigated. A deletion mutation in flhF abolished motility, flagella formation and flagellin synthesis, and introduction of flhF in trans complemented the defects. The flhF mutant revealed decreased expression of the class III and IV flagella genes, indicating that FlhF is a key regulator for the flagellar biogenesis of V. vulnificus. The influence of global regulatory proteins on the expression of flhF was examined and SmcR, a LuxR homologue, was found to downregulate flhF expression at the transcriptional level. SmcR represses flhF expression only in the stationary phase of growth and exerts its effects by directly binding to the flhF promoter region. Finally, an SmcR binding site, centred at 22.5 bp upstream of the transcription start site, was identified by a DNase I protection assay. The combined results demonstrate that a quorum sensing master regulator SmcR influences the motility and flagellar biogenesis of V. vulnificus through modulating the expression of FlhF in a growth-phase-dependent manner.
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