title: Imaging the uptake of nitrogen-fixing bacteria into larvae of the coral Acropora millepora.
abstract: Diazotrophic bacteria are instrumental in generating biologically usable forms of nitrogen by converting abundant dinitrogen gas (N2) into available forms, such as ammonium. Although nitrogen is crucial for coral growth, direct observation of associations between diazotrophs and corals has previously been elusive. We applied fluorescence in situ hybridization (FISH) and nanoscale secondary ion mass spectrometry to observe the uptake of (15)N-enriched diazotrophic Vibrio sp. isolated from Acropora millepora into conspecific coral larvae. Incorporation of Vibrio sp. cells was observed in coral larvae after 4-h incubation with enriched bacteria. Uptake was restricted to the aboral epidermis of larvae, where Vibrio cells clustered in elongated aggregations. Other bacterial associates were also observed in epidermal areas in FISH analyses. Although the fate and role of these bacteria requires additional investigation, this study describes a powerful approach to further explore cell associations and nutritional pathways in the early life stages of the coral holobiont.
authors.affiliation: ARC Centre of Excellence for Coral Reef Studies, and College of Marine and Environmental Sciences, James Cook University, Townsville, Queensland, Australia.|Centre for Marine Microbiology and Genetics, Australian Institute of Marine Science, Townsville MC, Townsville, Queensland, Australia.|AIMS@JCU, James Cook University, Townsville, Queensland, Australia.|IFREMER, Dyneco Pelagos, Plouzané, France.
authors.forename: Kimberley A
authors.initials: KA
authors.lastname: Lema
authors.affiliation: Centre for Microscopy, Characterisation and Analysis, The University of Western Australia, Stirling Hwy, Crawley, Western Australia, Australia.|The Oceans Institute, The University of Western Australia, Stirling Hwy, Crawley, Western Australia, Australia.
authors.forename: Peta L
authors.initials: PL
authors.lastname: Clode
authors.affiliation: Centre for Microscopy, Characterisation and Analysis, The University of Western Australia, Stirling Hwy, Crawley, Western Australia, Australia.
authors.forename: Matt R
authors.initials: MR
authors.lastname: Kilburn
authors.affiliation: School of Paediatrics and Child Heath, The University of Western Australia, Stirling Hwy, Crawley, Western Australia, Australia.
authors.forename: Ruth
authors.initials: R
authors.lastname: Thornton
authors.affiliation: ARC Centre of Excellence for Coral Reef Studies, and College of Marine and Environmental Sciences, James Cook University, Townsville, Queensland, Australia.|AIMS@JCU, James Cook University, Townsville, Queensland, Australia.
authors.forename: Bette L
authors.initials: BL
authors.lastname: Willis
authors.affiliation: Centre for Marine Microbiology and Genetics, Australian Institute of Marine Science, Townsville MC, Townsville, Queensland, Australia.|AIMS@JCU, James Cook University, Townsville, Queensland, Australia.
authors.forename: David G
authors.initials: DG
authors.lastname: Bourne
mesh_terms: D000818:Animals; D037421:Anthozoa / Q000382:microbiology*; D017404:In Situ Hybridization, Fluorescence; D007814:Larva; D009584:Nitrogen / Q000378:metabolism*; D009586:Nitrogen Fixation; D000072738:Nitrogen-Fixing Bacteria / Q000378:metabolism*
chemical_list: D009584:Nitrogen