SbfR positively regulates motility but negatively regulates biofilm formation and food-related surface colonization in Vibrio parahaemolyticus

Vibrio parahaemolyticus is a major seafood-borne pathogen whose environmental persistence is associated with biofilm formation. This study confirms SbfR (VP1649), a GntR-family regulator, as a critical suppressor of biofilm formation and promoter of motility in V. parahaemolyticus . The sbfR deletion mutant significantly impaired swimming and swarming motility, enhanced biofilm formation and biofilm matrix secrection, increased metabolic activity in biofilms, and promoted colonization on the surfaces of food-associated matirals, including shrimp ( Parapenaeopsis hardwickii ), crab ( Portunus trituberculatus ), polypropylene (PP) plastic, glass, and stainless steel. The sbfR gene mutant exhibited elevated cyclic di-GMP (c-di-GMP) concentrations and altered transcription of genes involved in biofilm matrix production ( cpsA and mfpA ), flagellar assembly ( flgM , flgA , flgB , flgK , motY , fliM , lafA , and fliD ), and c-di-GMP metabolism ( gepA , tpdA , vpa0198 , and scrA ). The complementation strain restored revert these observations back to the wild-type state. These findings demonstrate that SbfR orchestrates a lifestyle switch by suppressing c-di-GMP accumulation, regulating target key genes to inhibit biofilm formation and activate motility. • SbfR activates swimming and swarming motility. • SbfR inhibits biofilm formation, biofilm matrix secrection, and metabolic activity in biofilms. • SbfR inhibits colonization on the surfaces of food-associated matirals. • SbfR inhibits c-di-GMP production. • SbfR regulates transcription of genes involved in flagellar assembly, biofilm matrix production, and c-di-GMP metabolism.