title: Metabolic and physiological interdependencies in the Bathymodiolus azoricus symbiosis.
abstract: The hydrothermal vent mussel Bathymodiolus azoricus lives in an intimate symbiosis with two types of chemosynthetic Gammaproteobacteria in its gills: a sulfur oxidizer and a methane oxidizer. Despite numerous investigations over the last decades, the degree of interdependence between the three symbiotic partners, their individual metabolic contributions, as well as the mechanism of carbon transfer from the symbionts to the host are poorly understood. We used a combination of proteomics and genomics to investigate the physiology and metabolism of the individual symbiotic partners. Our study revealed that key metabolic functions are most likely accomplished jointly by B. azoricus and its symbionts: (1) CO2is pre-concentrated by the host for carbon fixation by the sulfur-oxidizing symbiont, and (2) the host replenishes essential biosynthetic TCA cycle intermediates for the sulfur-oxidizing symbiont. In return (3), the sulfur oxidizer may compensate for the host's putative deficiency in amino acid and cofactor biosynthesis. We also identified numerous 'symbiosis-specific' host proteins by comparing symbiont-containing and symbiont-free host tissues and symbiont fractions. These proteins included a large complement of host digestive enzymes in the gill that are likely involved in symbiont digestion and carbon transfer from the symbionts to the host.
authors: Institute of Pharmacy, Ernst-Moritz-Arndt-University, Greifswald, Germany.
authors: Ruby
authors: R
authors: Ponnudurai
authors: Department of Geoscience, University of Calgary, Calgary, Canada.
authors: Manuel
authors: 0000-0001-6904-0287
authors: M
authors: Kleiner
authors: Department of Symbiosis, Max Planck Institute for Marine Microbiology, Bremen, Germany.
authors: Lizbeth
authors: 0000-0001-5814-9471
authors: L
authors: Sayavedra
authors: Department of Symbiosis, Max Planck Institute for Marine Microbiology, Bremen, Germany.|Division of Microbial Ecology, University of Vienna, Vienna, Austria.
authors: Jillian M
authors: JM
authors: Petersen
authors: Institute of Microbiology, Ernst-Moritz-Arndt-University, Greifswald, Germany.
authors: Martin
authors: M
authors: Moche
authors: Institute of Microbiology, Ernst-Moritz-Arndt-University, Greifswald, Germany.
authors: Andreas
authors: A
authors: Otto
authors: Institute of Microbiology, Ernst-Moritz-Arndt-University, Greifswald, Germany.
authors: Dörte
authors: D
authors: Becher
authors: Marine Genomics Unit, Okinawa Institute of Science and Technology, Okinawa, Japan.
authors: Takeshi
authors: T
authors: Takeuchi
authors: Marine Genomics Unit, Okinawa Institute of Science and Technology, Okinawa, Japan.
authors: Noriyuki
authors: N
authors: Satoh
authors: Department of Symbiosis, Max Planck Institute for Marine Microbiology, Bremen, Germany.
authors: Nicole
authors: N
authors: Dubilier
authors: Institute of Pharmacy, Ernst-Moritz-Arndt-University, Greifswald, Germany.|Institute of Marine Biotechnology, Greifswald, Germany.
authors: Thomas
authors: T
authors: Schweder
authors: Institute of Pharmacy, Ernst-Moritz-Arndt-University, Greifswald, Germany.|Institute of Marine Biotechnology, Greifswald, Germany.
authors: Stephanie
authors: S
authors: Markert
mesh_terms: D000818:Animals; D053898:Biosynthetic Pathways; D020563:Gammaproteobacteria / Q000502:physiology*; D005880:Gills / Q000382:microbiology; D060086:Hydrothermal Vents; D008697:Methane / Q000378:metabolism; D049879:Mytilidae / Q000235:genetics / Q000382:microbiology*; D010084:Oxidation-Reduction; D020543:Proteome; D013045:Species Specificity; D013455:Sulfur / Q000378:metabolism; D013559:Symbiosis
chemical_list: D020543:Proteome; D013455:Sulfur; D008697:Methane