Contributions of tropodithietic acid and biofilm formation to the probiotic activity of Phaeobacter inhibens

• DOI: 10.1186/s12866-015-0617-z
• Publication Date: 2016-01-04T19:01:46Z
• Authors: Wenjing Zhao; Christine Dao; Murni Karim; Marta Gomez-Chiarri; David Rowley; David R. Nelson
• Keywords: Vibrio anguillarum; Transposon mutagenesis; Colonisation resistance

The probiotic bacterium Phaeobacter inhibens strain S4Sm, isolated from the inner shell surface of a healthy oyster, secretes antibiotic tropodithietic acid (TDA), is an excellent biofilm former, and increases oyster larvae survival when challenged with bacterial pathogens. In this study, we investigated specific roles TDA secretion formation in activity S4Sm.Mutations clpX (ATP-dependent ATPase) exoP (an exopolysaccharide biosynthesis gene) were created by insertional mutagenesis using homologous recombination. Mutation resulted loss production, no decline formation, ability to inhibit growth Vibrio tubiashii anguillarum co-colonization experiments. ~60% delayed inhibitory towards pathogens Both mutants exhibited reduced protect death tubiashii. Complementation mutations restored wild type phenotype. We also found that pre-colonization surfaces S4Sm was critical for pathogen colonization growth.Our observations demonstrate P. involves contributions both production TDA. Further, requires prior introduction pathogen.