Volume 12, Issue 2 p. 422-439

Metagenome and mRNA expression analyses of anaerobic methanotrophic archaea of the ANME-1 group

Anke Meyerdierks

Corresponding Author

Anke Meyerdierks

Max Planck Institute for Marine Microbiology, Celsiusstrasse 1, 28359 Bremen, Germany.

*E-mail [email protected]; Tel. (+49) (0)421 2028 941; Fax (+49) (0)421 2028 580. Search for more papers by this author
Michael Kube

Michael Kube

Max Planck Institute for Molecular Genetics, Ihnestrasse 63-73, 14195 Berlin, Germany.

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Ivaylo Kostadinov

Ivaylo Kostadinov

Max Planck Institute for Marine Microbiology, Celsiusstrasse 1, 28359 Bremen, Germany.

Jacobs University Bremen gGmbH, Campus Ring 1, 28759 Bremen, Germany.

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Hanno Teeling

Hanno Teeling

Max Planck Institute for Marine Microbiology, Celsiusstrasse 1, 28359 Bremen, Germany.

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Frank Oliver Glöckner

Frank Oliver Glöckner

Max Planck Institute for Marine Microbiology, Celsiusstrasse 1, 28359 Bremen, Germany.

Jacobs University Bremen gGmbH, Campus Ring 1, 28759 Bremen, Germany.

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Richard Reinhardt

Richard Reinhardt

Max Planck Institute for Molecular Genetics, Ihnestrasse 63-73, 14195 Berlin, Germany.

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Rudolf Amann

Rudolf Amann

Max Planck Institute for Marine Microbiology, Celsiusstrasse 1, 28359 Bremen, Germany.

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First published: 26 January 2010
Citations: 86

Summary

Microbial consortia mediating the anaerobic oxidation of methane with sulfate are composed of methanotrophic Archaea (ANME) and Bacteria related to sulfate-reducing Deltaproteobacteria. Cultured representatives are not available for any of the three ANME clades. Therefore, a metagenomic approach was applied to assess the genetic potential of ANME-1 archaea. In total, 3.4 Mbp sequence information was generated based on metagenomic fosmid libraries constructed directly from a methanotrophic microbial mat in the Black Sea. These sequence data represent, in 30 contigs, about 82–90% of a composite ANME-1 genome. The dataset supports the hypothesis of a reversal of the methanogenesis pathway. Indications for an assimilatory, but not for a dissimilatory sulfate reduction pathway in ANME-1, were found. Draft genome and expression analyses are consistent with acetate and formate as putative electron shuttles. Moreover, the dataset points towards downstream electron-accepting redox components different from the ones known from methanogenic archaea. Whereas catalytic subunits of [NiFe]-hydrogenases are lacking in the dataset, genes for an [FeFe]-hydrogenase homologue were identified, not yet described to be present in methanogenic archaea. Clustered genes annotated as secreted multiheme c-type cytochromes were identified, which have not yet been correlated with methanogenesis-related steps. The genes were shown to be expressed, suggesting direct electron transfer as an additional possible mode to shuttle electrons from ANME-1 to the bacterial sulfate-reducing partner.