Identification of VP0143 gene which modulates biofilm formation of Vibrio parahaemolyticus

Vibrio parahaemolyticus is a Gram-negative halophilic foodborne pathogen associated with seafood consumption and can cause acute inflammatory gastroenteritis. The biofilm formed by V. parahaemolyticus facilitates its colonization and persistence in the food production chain, posing a continuous threat to food safety. In this study, through transposon mutants screening, we identified a novel gene, VP0143, which positively regulated biofilm formation of V. parahaemolyticus. The VP0143 deletion mutant (Delta VP0143) exhibited less biofilm formation as determined by crystal violet staining assay and showed decreased viability of biofilm cells by XTT (2,3bis(2-methoxy-4-nitro-5-sulfophenyl)-2H-tetrazolium-5-carboxanilide) assay compared to the wild type strain. The Delta VP0143 strain also showed weakened flagella-mediated motility and surface hydrophobicity. Moreover, VP0143 deletion significantly affected the production of autoinducer-2 and exopolysaccharides in biofilm, and reduced Raman peak intensity of biofilm components. Microscopic analysis confirmed that biofilm formed by Delta VP0143 strain showed loosened structure. In addition, Delta VP0143 strain exhibited compromised ability to form biofilm on silicon wafers, glass and stainless-steel plates, as well as on shrimp and crab surfaces. All these defects were reversed in the complementation strain Delta VP0143C. RT-qPCR further indicated that expression of genes associated with biofilm formation was decreased after VP0143 deletion. Therefore, our data suggest that VP0143 is involved in regulating biofilm formation of V. parahaemolyticus and extend our understanding of genetic determinants of V. parahaemolyticus biofilm formation.