Deletion of fliC-02330 from Pseudoalteromonas marina affects the biofilm formation and the settlement and metamorphosis of Mytilus coruscus

Abstract:

[Background] Pseudoalteromonas is a group of Gram-negative bacteria ubiquitous in the marine environment.They exist in the seabed sediments and can secrete a large amount of extracellular products to form a biofilm,which induces the attachment of invertebrates.[Objective] To explore the effect of fliC-02330 deletion from Pseudoalteromonas marina on the biofilm formation and the activity of Mytilus coruscus.[Methods] We constructed the fliC-02330-deleted mutant of P. marina by gene knockout and then compared the phenotype,the biofilm-forming ability,and the effect on settlement and metamorphosis of M. coruscus between the mutant and the wild-type strain.Confocal laser scanning microscopy (CLSM) was conducted to detect changes in the content of extracellular products in the biofilm.[Results]Compared with the wild-type strain,the mutant showed wrinkled colony,weakened motility,thickened biofilm,and decreased activity of inducing the larval settlement and metamorphosis of M. coruscus.CLSM revealed that the fliC-02330-deleted mutant had decreased extracellular polysaccharide content and increased protein content.[Conclusion]The fliC-02330-deleted mutant has increased biofilm-forming ability and can inhibit the settlement and metamorphosis of M. coruscus larvae.This study provides a theoretical basis for exploring the mechanism of bacterial flagellin gene and the role of microorganisms in the settlement and metamorphosis of marine invertebrates.

Key words:Pseudoalteromonas marina;fliC-02330 gene;biofilm;Mytilus coruscus;settlement and metamorphosis