Isolation of an antimicrobial compound produced by bacteria associated with reef-building corals

• DOI: 10.7717/peerj.2275
• Publication Date: 2016-08-18T07:50:22Z
• Authors: Jean-Baptiste Raina; Dianne Tapiolas; Cherie A. Motti; Sylvain Foret; Torsten Seemann; Jan Tebben; Bette L. Willis; David G. Bourne
• Keywords: 0301 basic medicine; 570; antimicrobial compounds; QH301-705.5; Marine Biology; 03 medical and health sciences; anzsrc-for: 3103 Ecology; Biodefense; coral-associated bacteria; Disease; 14. Life underwater; anzsrc-for: 31 Biological Sciences; Biology (General); Alphaproteobacteria; disease; 0303 health sciences; Prevention; 3103 Ecology; R; 3 Good Health and Well Being; alphaproteobacteria; anzsrc-for: 3107 Microbiology; Antimicrobial compounds; 3107 Microbiology; Infectious Diseases; Emerging Infectious Diseases; anzsrc-for: 11 Medical and Health Sciences; anzsrc-for: 06 Biological Sciences; Medicine; 31 Biological Sciences; Coral-associated bacteria

Bacterial communities associated with healthy corals produce antimicrobial compounds that inhibit the colonization and growth of invasive microbes and potential pathogens. To date, however, bacteria-derived antimicrobial molecules have not been identified in reef-building corals. Here, we report the isolation of an antimicrobial compound produced byPseudovibriosp. P12, a common and abundant coral-associated bacterium. This strain was capable of metabolizing dimethylsulfoniopropionate (DMSP), a sulfur molecule produced in high concentrations by reef-building corals and playing a role in structuring their bacterial communities. Bioassay-guided fractionation coupled with nuclear magnetic resonance (NMR) and mass spectrometry (MS), identified the antimicrobial as tropodithietic acid (TDA), a sulfur-containing compound likely derived from DMSP catabolism. TDA was produced in large quantities byPseudovibriosp., and prevented the growth of two previously identified coral pathogens,Vibrio coralliilyticusandV. owensii, at very low concentrations (0.5 μg/mL) in agar diffusion assays. Genome sequencing ofPseudovibriosp. P12 identified gene homologs likely involved in the metabolism of DMSP and production of TDA. These results provide additional evidence for the integral role of DMSP in structuring coral-associated bacterial communities and underline the potential of these DMSP-metabolizing microbes to contribute to coral disease prevention.