Effects of Vibrio biofilms of different sources on settlement of plantigrades of the mussel Mytilus coruscus

Marine biofilms play a crucial role in the settlement of plantigrades of the mussel Mytilus coruscus, but the effect of Vibrio derived from different sources on the settlement of plantigrades of the mussel M. coruscus remains unknown. Ten marine Vibrio species were isolated from natural biofilms and the intestine of the wild adult mussel M. coruscus and identified to investigate the relationship between these biofilms and mussel planitigrade settlement. The results showed that Vibrio biofilm cell densities increased with the increasing initial cell density. All test Vibrio biofilms can significantly promote mussel settlement, and the percentage of plantigrade settlement ranged from 17% to 67%. The inducing activities of these bacterial biofilms were significantly correlated to the microbial biofilm density, and the correlation coefficient in V. crassostreae ECSMB14106 was the highest (0.8992). In addition, the inducing activity of these bacterial strains was not correlated to the source of Vibrio. This study showed that marine Vibrio of the different sources induced mussel settlement and the finding is important for understanding the potential molecular mechanism of the biofilms mediating the settlement process in this species.