title: Biology of a widespread uncultivated archaeon that contributes to carbon fixation in the subsurface.
abstract: Subsurface microbial life contributes significantly to biogeochemical cycling, yet it remains largely uncharacterized, especially its archaeal members. This 'microbial dark matter' has been explored by recent studies that were, however, mostly based on DNA sequence information only. Here, we use diverse techniques including ultrastuctural analyses to link genomics to biology for the SM1 Euryarchaeon lineage, an uncultivated group of subsurface archaea. Phylogenomic analyses reveal this lineage to belong to a widespread group of archaea that we propose to classify as a new euryarchaeal order ('Candidatus Altiarchaeales'). The representative, double-membraned species 'Candidatus Altiarchaeum hamiconexum' has an autotrophic metabolism that uses a not-yet-reported Factor420-free reductive acetyl-CoA pathway, confirmed by stable carbon isotopic measurements of archaeal lipids. Our results indicate that this lineage has evolved specific metabolic and structural features like nano-grappling hooks empowering this widely distributed archaeon to predominate anaerobic groundwater, where it may represent an important carbon dioxide sink.
authors.affiliation: 1] University of Regensburg, Department for Microbiology and Archaea Center, Universitaetsstrasse 31, 93053 Regensburg, Germany [2] Department of Earth and Planetary Science, University of California, Berkeley, 307 McCone Hall, Berkeley, CA 94720, USA.
authors.forename: Alexander J
authors.initials: AJ
authors.lastname: Probst
authors.affiliation: University of Vienna, Division of Computational Systems Biology, Althanstraße 14, A-1090 Wien, Austria.
authors.forename: Thomas
authors.initials: T
authors.lastname: Weinmaier
authors.affiliation: Institut Pasteur, Unité Biologie Moléculaire du Gene chez les Extrêmophiles, Département de Microbiologie, Paris, 75724 Cedex 15, France.
authors.forename: Kasie
authors.initials: K
authors.lastname: Raymann
authors.affiliation: 1] University of Regensburg, Department for Microbiology and Archaea Center, Universitaetsstrasse 31, 93053 Regensburg, Germany [2] Medical University Graz, Department of Internal Medicine, Auenbruggerplatz 15, 8036 Graz, Austria.
authors.forename: Alexandra
authors.initials: A
authors.lastname: Perras
authors.affiliation: Department of Earth and Planetary Science, University of California, Berkeley, 307 McCone Hall, Berkeley, CA 94720, USA.
authors.forename: Joanne B
authors.initials: JB
authors.lastname: Emerson
authors.affiliation: University of Vienna, Division of Computational Systems Biology, Althanstraße 14, A-1090 Wien, Austria.
authors.forename: Thomas
authors.initials: T
authors.lastname: Rattei
authors.affiliation: Ludwig Maximilians University of Munich (LMU), Biozentrum, Department of Biology I, 82152 Planegg-Martinsried, Germany.
authors.forename: Gerhard
authors.initials: G
authors.lastname: Wanner
authors.affiliation: 1] Ludwig Maximilians University of Munich (LMU), Biozentrum, Department of Biology I, 82152 Planegg-Martinsried, Germany [2] Cell Biology and LOEWE Research Centre for Synthetic Microbiology (Synmikro), Karl-von-Frisch-Str. 8, 35043 Marburg, Germany.
authors.forename: Andreas
authors.initials: A
authors.lastname: Klingl
authors.affiliation: Department of Microbiology, Faculty of Biology, University of Freiburg, Schänzlestr. 1, 79104 Freiburg, Germany.
authors.forename: Ivan A
authors.initials: IA
authors.lastname: Berg
authors.affiliation: Organic Geochemistry Group, MARUM-Center for Marine Environmental Sciences and Department of Geosciences, University of Bremen, 28359 Bremen, Germany.
authors.forename: Marcos
authors.initials: M
authors.lastname: Yoshinaga
authors.affiliation: Organic Geochemistry Group, MARUM-Center for Marine Environmental Sciences and Department of Geosciences, University of Bremen, 28359 Bremen, Germany.
authors.forename: Bernhard
authors.initials: B
authors.lastname: Viehweger
authors.affiliation: Organic Geochemistry Group, MARUM-Center for Marine Environmental Sciences and Department of Geosciences, University of Bremen, 28359 Bremen, Germany.
authors.forename: Kai-Uwe
authors.initials: KU
authors.lastname: Hinrichs
authors.affiliation: Department of Earth and Planetary Science, University of California, Berkeley, 307 McCone Hall, Berkeley, CA 94720, USA.
authors.forename: Brian C
authors.initials: BC
authors.lastname: Thomas
authors.affiliation: University of Regensburg, Department for Microbiology and Archaea Center, Universitaetsstrasse 31, 93053 Regensburg, Germany.
authors.forename: Sandra
authors.initials: S
authors.lastname: Meck
authors.affiliation: University of Regensburg, Department for Microbiology and Archaea Center, Universitaetsstrasse 31, 93053 Regensburg, Germany.
authors.forename: Anna K
authors.initials: AK
authors.lastname: Auerbach
authors.affiliation: Institute of Experimental and Applied Physics, University of Regensburg, Universitaetsstrasse 31, 93053 Regensburg, Germany.
authors.forename: Matthias
authors.initials: M
authors.lastname: Heise
authors.affiliation: Division of Microbial Ecology, Department of Microbiology and Ecosystem Science, Faculty of Life Sciences, University of Vienna, Althanstr. 14, 1090 Vienna, Austria.
authors.forename: Arno
authors.initials: A
authors.lastname: Schintlmeister
authors.affiliation: Division of Microbial Ecology, Department of Microbiology and Ecosystem Science, Faculty of Life Sciences, University of Vienna, Althanstr. 14, 1090 Vienna, Austria.
authors.forename: Markus
authors.initials: M
authors.lastname: Schmid
authors.affiliation: Division of Microbial Ecology, Department of Microbiology and Ecosystem Science, Faculty of Life Sciences, University of Vienna, Althanstr. 14, 1090 Vienna, Austria.
authors.forename: Michael
authors.initials: M
authors.lastname: Wagner
authors.affiliation: Institut Pasteur, Unité Biologie Moléculaire du Gene chez les Extrêmophiles, Département de Microbiologie, Paris, 75724 Cedex 15, France.
authors.forename: Simonetta
authors.initials: S
authors.lastname: Gribaldo
authors.affiliation: Department of Earth and Planetary Science, University of California, Berkeley, 307 McCone Hall, Berkeley, CA 94720, USA.
authors.forename: Jillian F
authors.initials: JF
authors.lastname: Banfield
authors.affiliation: 1] University of Regensburg, Department for Microbiology and Archaea Center, Universitaetsstrasse 31, 93053 Regensburg, Germany [2] Medical University Graz, Department of Internal Medicine, Auenbruggerplatz 15, 8036 Graz, Austria [3] BioTechMed Graz, Krenngasse 37, 8010 Graz, Austria.
authors.forename: Christine
authors.initials: C
authors.lastname: Moissl-Eichinger
mesh_terms: D001105:Archaea / Q000145:classification / Q000235:genetics / Q000254:growth & development / Q000378:metabolism*; D002244:Carbon / Q000378:metabolism*; D057486:Carbon Cycle; D060587:Groundwater / Q000032:analysis / Q000382:microbiology*; D008969:Molecular Sequence Data; D010802:Phylogeny
chemical_list: D002244:Carbon