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

Environ Microbiol. 2010 Feb;12(2):422-39. doi: 10.1111/j.1462-2920.2009.02083.x. Epub 2009 Oct 29.


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.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Base Sequence
  • Cytochromes c / genetics
  • Euryarchaeota / classification
  • Euryarchaeota / genetics*
  • Euryarchaeota / metabolism*
  • Hydrogenase / genetics
  • Iron-Sulfur Proteins / genetics
  • Metagenome*
  • Metagenomics
  • Methane / metabolism
  • Molecular Sequence Data
  • Oceans and Seas
  • Oxidation-Reduction
  • RNA, Messenger / metabolism*


  • Iron-Sulfur Proteins
  • RNA, Messenger
  • Cytochromes c
  • iron hydrogenase
  • Hydrogenase
  • Methane

Associated data

  • GENBANK/FP565147