Abstract: In this study, a luxS-deleted mutant of Vibrio parahaemolyticus was successfully constructed by homologous recombination technology, and the growth capacity, 4,5-dihydroxy-2,3-pentanedione (DPD) production, biofilm formation, motility, drug susceptibility, extracellular protein-secreting capacity, and quorum sensing-related gene expression of the wild and mutant strains were compared to understand the effects of luxS gene deletion in the LuxS/AI-2 quorum sensing system on the biological characteristics of V. parahaemolyticus. The results showed that the deletion of the luxS gene did not affect the drug susceptibility or growth capacity of the strain. Compared with the wild-type strain, the DPD production and mobility of the mutant strain was significantly reduced, while the capacity of biofilm formation and extracellular protease secretion after 24 hours of incubation was significantly enhanced. The real-time polymerase chain reaction (PCR) results showed that the expression of the flagellar synthesis gene flgM significantly increased, while the expression of the hemolysin secretion-related gene toxS, the flagella synthesis gene flaA and the outer membrane protein gene ompW decreased significantly in the mutant strain. This study provides a basis for further research on the regulation mechanism of the LuxS/AI-2 quorum sensing system on the biological characteristics of V. parahaemolyticus, which will be helpful for the prevention and control of V. parahaemolyticus.

Key words: Vibrio parahaemolyticus; luxS gene; quorum sensing; biofilm