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Lelchat F, Mocaer PY, Ojima T, Michel G, Sarthou G, Bucciarelli E, Cérantola S, Colliec-Jouault S, Boisset C, Baudoux AC. Viral degradation of marine bacterial exopolysaccharides. FEMS Microbiol Ecol 2020; 95:5498295. [PMID: 31125051 DOI: 10.1093/femsec/fiz079] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2019] [Accepted: 05/23/2019] [Indexed: 11/14/2022] Open
Abstract
The identification of the mechanisms by which marine dissolved organic matter (DOM) is produced and regenerated is critical to develop robust prediction of ocean carbon cycling. Polysaccharides represent one of the main constituents of marine DOM and their degradation is mainly attributed to polysaccharidases derived from bacteria. Here, we report that marine viruses can depolymerize the exopolysaccharides (EPS) excreted by their hosts using five bacteriophages that infect the notable EPS producer, Cobetia marina DSMZ 4741. Degradation monitorings as assessed by gel electrophoresis and size exclusion chromatography showed that four out of five phages carry structural enzymes that depolymerize purified solution of Cobetia marina EPS. The depolymerization patterns suggest that these putative polysaccharidases are constitutive, endo-acting and functionally diverse. Viral adsorption kinetics indicate that the presence of these enzymes provides a significant advantage for phages to adsorb onto their hosts upon intense EPS production conditions. The experimental demonstration that marine phages can display polysaccharidases active on bacterial EPS lead us to question whether viruses could also contribute to the degradation of marine DOM and modify its bioavailability. Considering the prominence of phages in the ocean, such studies may unveil an important microbial process that affects the marine carbon cycle.
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Affiliation(s)
- F Lelchat
- Laboratoire BMM, centre Ifremer de Brest, ZI pointe du diable, 29280 Plouzané, France
| | - P Y Mocaer
- Sorbonne Université, CNRS, UMR7144 Adaptation et Diversité en Milieu Marin, Station Biologique de Roscoff, Roscoff, France
| | - T Ojima
- Laboratory of Marine Biotechnology and Microbiology, Graduate School of Fisheries Sciences, Hokkaido University, Minato-cho 3-1-1, Hakodate 041-8611, Japan
| | - G Michel
- Sorbonne Université, CNRS, Laboratoire de Biologie Intégrative des Modèles Marins UMR 8227, Station Biologique de Roscoff, Roscoff, France
| | - G Sarthou
- CNRS, Université de Brest, IRD, Ifremer, UMR 6539/LEMAR/IUEM, Technopôle Brest Iroise, Place Nicolas Copernic, 29280 Plouzané, France
| | - E Bucciarelli
- CNRS, Université de Brest, IRD, Ifremer, UMR 6539/LEMAR/IUEM, Technopôle Brest Iroise, Place Nicolas Copernic, 29280 Plouzané, France
| | - S Cérantola
- Service commun de résonnance magnétique nucléaire, Faculté de science de Brest, Université de Bretagne Occidentale, 6 av. Victor Le Gorgeu, 29238 Brest Cedex 3, France
| | - S Colliec-Jouault
- Laboratoire EM3B, Centre Ifremer Atlantique - Rue de l'Ile d'Yeu - 44311 Nantes, France
| | - C Boisset
- Service commun de chromatographie, CERMAV-CNRS, 601 rue de la chimie, St Martin d'Hère, 38041 Grenoble, France
| | - A-C Baudoux
- Sorbonne Université, CNRS, UMR7144 Adaptation et Diversité en Milieu Marin, Station Biologique de Roscoff, Roscoff, France
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