title: Biogeography and environmental genomics of the Roseobacter-affiliated pelagic CHAB-I-5 lineage.
abstract: The identification and functional characterization of microbial communities remains a prevailing topic in microbial oceanography as information on environmentally relevant pelagic prokaryotes is still limited. The Roseobacter group, an abundant lineage of marine Alphaproteobacteria, can constitute large proportions of the bacterioplankton. Roseobacters also occur associated with eukaryotic organisms and possess streamlined as well as larger genomes from 2.2 to >5 Mpb. Here, we show that one pelagic cluster of this group, CHAB-I-5, occurs globally from tropical to polar regions and accounts for up to 22% of the active North Sea bacterioplankton in the summer. The first sequenced genome of a CHAB-I-5 organism comprises 3.6 Mbp and exhibits features of an oligotrophic lifestyle. In a metatranscriptome of North Sea surface waters, 98% of the encoded genes were present, and genes encoding various ABC transporters, glutamate synthase and CO oxidation were particularly upregulated. Phylogenetic gene content analyses of 41 genomes of the Roseobacter group revealed a unique cluster of pelagic organisms distinct from other lineages of this group, highlighting the adaptation to life in nutrient-depleted environments.
authors: Institute for Chemistry and Biology of the Marine Environment, University of Oldenburg, Oldenburg D-26111, Germany.
authors: Sara
authors: S
authors: Billerbeck
authors: Genomic and Applied Microbiology &Göttingen Genomics Laboratory, Institute of Microbiology and Genetics, University of Göttingen, Göttingen D-37077, Germany.
authors: Bernd
authors: B
authors: Wemheuer
authors: Genomic and Applied Microbiology &Göttingen Genomics Laboratory, Institute of Microbiology and Genetics, University of Göttingen, Göttingen D-37077, Germany.
authors: Sonja
authors: S
authors: Voget
authors: Genomic and Applied Microbiology &Göttingen Genomics Laboratory, Institute of Microbiology and Genetics, University of Göttingen, Göttingen D-37077, Germany.
authors: Anja
authors: 0000-0002-2473-6202
authors: A
authors: Poehlein
authors: Institute for Chemistry and Biology of the Marine Environment, University of Oldenburg, Oldenburg D-26111, Germany.
authors: Helge-Ansgar
authors: HA
authors: Giebel
authors: Institute for Chemistry and Biology of the Marine Environment, University of Oldenburg, Oldenburg D-26111, Germany.
authors: Thorsten
authors: T
authors: Brinkhoff
authors: Department of Systems Biology, Technical University of Denmark, Lyngby DK-2800 Kgs, Denmark.
authors: Lone
authors: L
authors: Gram
authors: Center for Environmental Diagnostics and Bioremediation, University of West Florida, Pensacola, Florida 32514, USA.
authors: Wade H
authors: WH
authors: Jeffrey
authors: Genomic and Applied Microbiology &Göttingen Genomics Laboratory, Institute of Microbiology and Genetics, University of Göttingen, Göttingen D-37077, Germany.
authors: Rolf
authors: 0000-0002-8646-7925
authors: R
authors: Daniel
authors: Institute for Chemistry and Biology of the Marine Environment, University of Oldenburg, Oldenburg D-26111, Germany.
authors: Meinhard
authors: M
authors: Simon
mesh_terms: D018528:ATP-Binding Cassette Transporters / Q000235:genetics; D000064:Acclimatization; D003081:Cold Climate; D020869:Gene Expression Profiling; D016680:Genome, Bacterial; D005970:Glutamate Synthase / Q000235:genetics; D056186:Metagenomics; D009659:North Sea; D010802:Phylogeny; D058974:Phylogeography; D010933:Plankton; D012336:RNA, Ribosomal, 16S; D041904:Roseobacter / Q000145:classification / Q000235:genetics* / Q000502:physiology; D012623:Seawater / Q000382:microbiology*; D014871:Water Microbiology
chemical_list: D018528:ATP-Binding Cassette Transporters; D012336:RNA, Ribosomal, 16S; D005970:Glutamate Synthase