Roles of rpoN in biofilm formation of Vibrio alginolyticus HN08155 at different cell densities

摘要

RpoN (?54) as a global regulator controls crucialvirulence-associated phenotype, which can regulate flagellum and exopolysaccharides (EPS) during pathogenic biofilm formation. However, the knowledge of the roles of rpoN in biofilm formation of V. alginolyticus is limited, especially at different cell densities. Herein, deletion mutant strain ?rpoN, complementary strain ?rpoN-C and negative control strain ?rpoN-Z were constructed to investigate the effects of rpoN on biofilm formation of V. alginolyticus HN08155 based on flagellum and EPS at different cell density conditions. The results showed that all of strains can form biofilm, and biofilms of strains with rpoN were formed at low cell density (LCD) and detached at high cell density (HCD), while those of ?rpoN and ?rpoN-Z were absent at LCD and accumulated excessively with a spotty pellicle at HCD without detaching. The EPS contents of strains with rpoN was greater than that of ?rpoN and ?rpoN-Z at LCD, while the opposite trends were observed at HCD. The expression levels of rpoN were quantified, which were consistent with the trend of biofilm formation. It?s worth noting that absence of rpoN resulted in the failure of biofilm detachment, lacking of flagellum and decreasing motility, indicating that rpoN was not necessary for biofilm formation, but it was essential for biofilm detachment.