Members of the genus Methylobacter are inferred to account for the majority of aerobic methane oxidation in oxic soils from a freshwater wetland

  • Sites: US-OWC
  • Publication Type: JOUR
  • Authors: Smith, G. J.; Angle, J. C.; Solden, L. M.; Borton, M. A.; Morin, T. H.; Daly, R. A.; Johnston, M. D.; Stefanik, K. C.; Wolfe, R.; Bohrer, G.; Wrighton, K. C.

  • Microbial carbon degradation and methanogenesis in wetland soils
    generate a large proportion of atmospheric methane, a highly potent greenhouse
    gas. Despite their potential to mitigate greenhouse gas emissions, knowledge about
    methane-consuming methanotrophs is often limited to lower-resolution single-gene
    surveys that fail to capture the taxonomic and metabolic diversity of these microorganisms
    in soils. Here our objective was to use genome-enabled approaches to investigate
    methanotroph membership, distribution, and in situ activity across spatial
    and seasonal gradients in a freshwater wetland near Lake Erie. 16S rRNA gene analyses
    demonstrated that members of the methanotrophic Methylococcales were dominant,
    with the dominance largely driven by the relative abundance of four taxa, and
    enriched in oxic surface soils. Three methanotroph genomes from assembled soil
    metagenomes were assigned to the genus Methylobacter and represented the most
    abundant methanotrophs across the wetland. Paired metatranscriptomes confirmed
    that these Old Woman Creek (OWC) Methylobacter members accounted for nearly all
    the aerobic methanotrophic activity across two seasons. In addition to having the
    capacity to couple methane oxidation to aerobic respiration, these new genomes
    encoded denitrification potential that may sustain energy generation in soils with
    lower dissolved oxygen concentrations. We further show that Methylobacter members
    that were closely related to the OWC members were present in many other
    high-methane-emitting freshwater and soil sites, suggesting that this lineage could
    participate in methane consumption in analogous ecosystems. This work contributes
    to the growing body of research suggesting that Methylobacter may represent critical
    mediators of methane fluxes in freshwater saturated sediments and soils worldwide.

  • Journal: mBio
  • Funding Agency: U.S. Department of Energy (DOE); NSF;
  • Citation Information:
  • Volume: 9
  • No: 6
  • Pages: e00815-18
  • Publication Year: 2018/12
  • DOI: 10 .1128/mBio.00815-18