title: Chemosynthetic symbionts of marine invertebrate animals are capable of nitrogen fixation.
abstract: Chemosynthetic symbioses are partnerships between invertebrate animals and chemosynthetic bacteria. The latter are the primary producers, providing most of the organic carbon needed for the animal host's nutrition. We sequenced genomes of the chemosynthetic symbionts from the lucinid bivalve Loripes lucinalis and the stilbonematid nematode Laxus oneistus. The symbionts of both host species encoded nitrogen fixation genes. This is remarkable as no marine chemosynthetic symbiont was previously known to be capable of nitrogen fixation. We detected nitrogenase expression by the symbionts of lucinid clams at the transcriptomic and proteomic level. Mean stable nitrogen isotope values of Loripes lucinalis were within the range expected for fixed atmospheric nitrogen, further suggesting active nitrogen fixation by the symbionts. The ability to fix nitrogen may be widespread among chemosynthetic symbioses in oligotrophic habitats, where nitrogen availability often limits primary productivity.
authors: Department of Microbiology and Ecosystem Science, Division of Microbial Ecology, Research Network Chemistry meets Microbiology, University of Vienna, Althanstrasse 14, Vienna 1090, Austria.|Max Planck Institute for Marine Microbiology, Celsiusstrasse 1, Bremen 28359, Germany.
authors: Jillian M
authors: JM
authors: Petersen
authors: Max Planck Institute for Marine Microbiology, Celsiusstrasse 1, Bremen 28359, Germany.
authors: Anna
authors: A
authors: Kemper
authors: Max Planck Institute for Marine Microbiology, Celsiusstrasse 1, Bremen 28359, Germany.
authors: Harald
authors: H
authors: Gruber-Vodicka
authors: Department of Microbiology and Ecosystem Science, Division of Microbial Ecology, Research Network Chemistry meets Microbiology, University of Vienna, Althanstrasse 14, Vienna 1090, Austria.
authors: Ulisse
authors: http://orcid.org/0000-0002-0816-6158
authors: U
authors: Cardini
authors: Centre for Marine Biodiversity, Exploitation and Conservation (MARBEC), UMR 9190, IRD-IFREMER-CNRS-UM, Université de Montpellier, Montpellier Cedex 5 34095, France.|Department of Coastal Systems and Utrecht University, NIOZ Royal Netherlands Institute for Sea Research, PO Box 59, 1790 AB Den Burg, Texel, The Netherlands.
authors: Matthijs
authors: http://orcid.org/0000-0002-9837-3803
authors: M
authors: van der Geest
authors: Department of Geoscience, University of Calgary, 2500 University Drive Northwest, Alberta T2N 1N4, Canada.
authors: Manuel
authors: http://orcid.org/0000-0001-6904-0287
authors: M
authors: Kleiner
authors: Archaea Biology and Ecogenomics Division, Department of Ecogenomics and Systems Biology, University of Vienna, Althanstrasse 14, Vienna 1090, Austria.
authors: Silvia
authors: S
authors: Bulgheresi
authors: Department of Microbiology and Ecosystem Science, Division of Microbial Ecology, Research Network Chemistry meets Microbiology, University of Vienna, Althanstrasse 14, Vienna 1090, Austria.
authors: Marc
authors: M
authors: Mußmann
authors: Department of Microbiology and Ecosystem Science, Division of Microbial Ecology, Research Network Chemistry meets Microbiology, University of Vienna, Althanstrasse 14, Vienna 1090, Austria.
authors: Craig
authors: C
authors: Herbold
authors: Max Planck Institute for Marine Microbiology, Celsiusstrasse 1, Bremen 28359, Germany.
authors: Brandon K B
authors: http://orcid.org/0000-0002-1878-4363
authors: BK
authors: Seah
authors: Max Planck Institute for Marine Microbiology, Celsiusstrasse 1, Bremen 28359, Germany.
authors: Chakkiath Paul
authors: CP
authors: Antony
authors: Department of Geoscience, University of Calgary, 2500 University Drive Northwest, Alberta T2N 1N4, Canada.
authors: Dan
authors: D
authors: Liu
authors: Department of Microbiology and Ecosystem Science, Division of Microbial Ecology, Research Network Chemistry meets Microbiology, University of Vienna, Althanstrasse 14, Vienna 1090, Austria.
authors: Alexandra
authors: A
authors: Belitz
authors: HYDRA Institute for Marine Sciences, Elba Field Station, Campo nell'Elba, Livorno 54037, Italy.
authors: Miriam
authors: M
authors: Weber
mesh_terms: D000818:Animals; D059001:Aquatic Organisms / Q000382:microbiology*; D001419:Bacteria / Q000201:enzymology* / Q000235:genetics; D049872:Bivalvia / Q000382:microbiology*; D000073560:Chromadorea / Q000382:microbiology*; D020869:Gene Expression Profiling; D009586:Nitrogen Fixation; D009591:Nitrogenase / Q000235:genetics; D020543:Proteome / Q000032:analysis; D017422:Sequence Analysis, DNA; D013559:Symbiosis
chemical_list: D020543:Proteome; D009591:Nitrogenase