H-NS is an activator of exopolysaccharide biosynthesis genes transcription in Vibrio parahaemolyticus.

Vibrio parahaemolyticus is capable of surviving in biofilm communities attached to biotic and abiotic surfaces. The exopolysaccharide (EPS) plays a key role in the maturing of the biofilm. The VPA1403-1412 (cpsA-J) operon is responsible for EPS production in V. parahaemolyticus. The expression of cpsA-J is controlled by ScrABC, intracellular concentration of c-di-GMP, CpsS-CpsR-CpsQ regulatory cascade, and quorum sensing. The data presented here showed that H-NS activates the EPS-dependent bacterial colony morphology and the transcription of cpsQ and cpsA-J. H-NS has negative regulatory activity on scrABC transcription, and thereby may result in enhancing the intracellular concentration of c-di-GMP. Thus, a regulatory circuit involved in regulating cpsA-J/EPS production by H-NS, ScrABC and CpsQ was identified in V. parahaemolyticus.