title: Continental-scale variation in seaweed host-associated bacterial communities is a function of host condition, not geography.
abstract: Interactions between hosts and associated microbial communities can fundamentally shape the development and ecology of 'holobionts', from humans to marine habitat-forming organisms such as seaweeds. In marine systems, planktonic microbial community structure is mainly driven by geography and related environmental factors, but the large-scale drivers of host-associated microbial communities are largely unknown. Using 16S-rRNA gene sequencing, we characterized 260 seaweed-associated bacterial and archaeal communities on the kelp Ecklonia radiata from three biogeographical provinces spanning 10° of latitude and 35° of longitude across the Australian continent. These phylogenetically and taxonomically diverse communities were more strongly and consistently associated with host condition than geographical location or environmental variables, and a 'core' microbial community characteristic of healthy kelps appears to be lost when hosts become stressed. Microbial communities on stressed individuals were more similar to each other among locations than those on healthy hosts. In contrast to biogeographical patterns of planktonic marine microbial communities, host traits emerge as critical determinants of associated microbial community structure of these holobionts, even at a continental scale.
authors.affiliation: Centre for Marine Bio-Innovation and School of Biological, Earth and Environmental Sciences, University of New South Wales, Sydney, NSW, 2052, Australia.|Evolution and Ecology Research Centre, School of Biological, Earth and Environmental Sciences, University of New South Wales, Sydney, NSW, 2052, Australia.|Sydney Institute of Marine Science (SIMS), 19 Chowder Bay Road, Mosman, NSW, 2088, Australia.
authors.forename: Ezequiel M
authors.initials: EM
authors.lastname: Marzinelli
authors.affiliation: Centre for Marine Bio-Innovation and School of Biological, Earth and Environmental Sciences, University of New South Wales, Sydney, NSW, 2052, Australia.|Evolution and Ecology Research Centre, School of Biological, Earth and Environmental Sciences, University of New South Wales, Sydney, NSW, 2052, Australia.|Sydney Institute of Marine Science (SIMS), 19 Chowder Bay Road, Mosman, NSW, 2088, Australia.
authors.forename: Alexandra H
authors.initials: AH
authors.lastname: Campbell
authors.affiliation: Centre for Marine Bio-Innovation and School of Biological, Earth and Environmental Sciences, University of New South Wales, Sydney, NSW, 2052, Australia.|School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, NSW, 2052, Australia.
authors.forename: Enrique
authors.initials: E
authors.lastname: Zozaya Valdes
authors.affiliation: Centre for Marine Bio-Innovation and School of Biological, Earth and Environmental Sciences, University of New South Wales, Sydney, NSW, 2052, Australia.|Evolution and Ecology Research Centre, School of Biological, Earth and Environmental Sciences, University of New South Wales, Sydney, NSW, 2052, Australia.|Sydney Institute of Marine Science (SIMS), 19 Chowder Bay Road, Mosman, NSW, 2088, Australia.
authors.forename: Adriana
authors.initials: A
authors.lastname: Vergés
authors.affiliation: Centre for Marine Bio-Innovation and School of Biological, Earth and Environmental Sciences, University of New South Wales, Sydney, NSW, 2052, Australia.|School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, NSW, 2052, Australia.
authors.forename: Shaun
authors.initials: S
authors.lastname: Nielsen
authors.affiliation: UWA Oceans Institute & School of Plant Biology, University of Western Australia, Crawley, WA, 6009, Australia.
authors.forename: Thomas
authors.initials: T
authors.lastname: Wernberg
authors.affiliation: UWA Oceans Institute & School of Plant Biology, University of Western Australia, Crawley, WA, 6009, Australia.
authors.forename: Thibaut
authors.initials: T
authors.lastname: de Bettignies
authors.affiliation: UWA Oceans Institute & School of Plant Biology, University of Western Australia, Crawley, WA, 6009, Australia.
authors.forename: Scott
authors.initials: S
authors.lastname: Bennett
authors.affiliation: Center for Microbial Genetics and Genomics, Northern Arizona University, 1298 S Knoles Drive, PO Box 4073, Flagstaff, AZ, 86011-4073, USA.
authors.forename: J Gregory
authors.initials: JG
authors.lastname: Caporaso
authors.affiliation: Centre for Marine Bio-Innovation and School of Biological, Earth and Environmental Sciences, University of New South Wales, Sydney, NSW, 2052, Australia.|School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, NSW, 2052, Australia.
authors.forename: Torsten
authors.initials: T
authors.lastname: Thomas
authors.affiliation: Centre for Marine Bio-Innovation and School of Biological, Earth and Environmental Sciences, University of New South Wales, Sydney, NSW, 2052, Australia.|Sydney Institute of Marine Science (SIMS), 19 Chowder Bay Road, Mosman, NSW, 2088, Australia.|Advanced Environmental Biotechnology Centre, Nanyang Technical University, Singapore, 637551, Singapore.
authors.forename: Peter D
authors.initials: PD
authors.lastname: Steinberg
mesh_terms: D001105:Archaea / Q000145:classification* / Q000235:genetics; D001315:Australia; D001419:Bacteria / Q000145:classification* / Q000235:genetics; D017753:Ecosystem; D004777:Environment; D005843:Geography; D006801:Humans; D044423:Kelp / Q000382:microbiology*; D064307:Microbiota / Q000235:genetics* / Q000502:physiology; D010641:Phenotype; D010802:Phylogeny; D010933:Plankton / Q000382:microbiology*; D012336:RNA, Ribosomal, 16S / Q000235:genetics
chemical_list: D012336:RNA, Ribosomal, 16S