Effects of marinebacteria from silanizing surfaces on plantigrade settlement of the mussel Mytilus coruscus

To understand plantigrade settlement of the mussel Mytilus coruscus in response to the different bacterial strains isolated from silanizing surfaces, the relationship between bacterial biofilms and plantigrade settlement was conducted.All test marine bacteria were isolated from the biofilms formed on the silanizing surfaces and identified by 16S rDNA gene sequences.In the laboratory, the effects of monospecific bacterial biofilms on settlement of M.coruscus plantigrades were also investigated.The phylogenetic tree derived from the elected 16S rDNA sequence was constructed and the genetic distance was calculated.The results showed that the density of monospecific bacterial biofilms increased with the initial incubation density and all test bacterial biofilms showed significantly inducing activity on settlement of M.coruscus plantigrades.Among the 9 bacterial species, the biofilms of Staphylococcus sp.1 and Cobetia sp.1 induced the lower percentage of plantigrade settlement of 47% and 43%, and there was no signification correlation between the settlement and biofilm density.The biofilms of other 7 bacteria showed moderate inducing activity, and significant correlation between cell densities of these 7 bacterial strains and inducing activity were observed.The inducing activity of individual bacterial isolates was not correlated with their phylogenetic relationship.Thus, marine bacteria derived from biofilms developed on silanizing surfaces can promote the settlement of plantigrades of the mussel M.coruscus. Those results will provide some useful information to understand the relationship between bacterial biofilms and the settlement mechanism of M.coruscus plantigrades.