U.S. Department of Energy Office of Biological and Environmental Research

BER Research Highlights

Comparative Genomics Reveal Functional Diversification of the Methanogen Methanosarcina mazei
Published: March 10, 2015
Posted: April 01, 2015

Methanogenic archaea play a major role in global carbon cycle processes, participating in the conversion of organic carbon to the greenhouse gas methane in oxygen-limited environments such as waterlogged soils and wetland sediments. Different types of methanogens are capable of converting either hydrogen and carbon dioxide or intermediate fermentation products (e.g., ace­tate and methanol) into methane; both processes are key components of carbon decomposi­tion food webs. In a new study, researchers at the University of Illinois have completed a compara­tive genomics study on 56 different isolates of the metabolically versatile methanogen Methanosarcina mazei cultivated from sediments of the Columbia River in Oregon. While all isolates are members of the same species, they showed a surprising degree of genomic diversity and formed a distinct pattern of subgroups (i.e., clades) based on their site of isolation. The investigators were able to identify a core genome shared by all isolates, but other genetic elements were variable in distribution and showed evidence of transfer between different clades of M. mazei. Several of the variable genes encoding proteins involved the methanogenic metabol­ism, cofactor utilization, and (most intriguingly) uptake of organic substrates. These observations led the researchers to hypothesize that M. mazei has evolved into strains optimized for specific ecological niches in the sedimentary environments, a phenomenon that has been observed in environmental populations of bacteria. This hypothesis was supported by physiological experi­ments showing that isolates from different M. mazei clades varied in their ability to use the organic compound trimethylamine for methanogensis. These results advance our mechanistic understanding of a key step in the global carbon cycle and highlight the importance of analyzing metabolically significant differences that occur in microbes at the subspecies level.

Reference: Youngblut, N. D., J. S. Wirth, J. R. Henriksen, M. Smith, H. Simon, W. W. Metcalf, and R. J. Whitaker. 2015. “Genomic and Phenotypic Differentiation Among Methanosarcina mazei Populations from Columbia River Sediment,” The ISME Journal, DOI: 10.1038/ismej.2015.31. (Reference link)

Contact: Joseph Graber, SC-23.2, (301) 903-1239
Topic Areas:

  • Research Area: Subsurface Biogeochemical Research
  • Research Area: Carbon Cycle, Nutrient Cycling
  • Research Area: Genomic Analysis and Systems Biology
  • Research Area: Microbes and Communities

Division: SC-23.2 Biological Systems Science Division, BER


BER supports basic research and scientific user facilities to advance DOE missions in energy and environment. More about BER

Recent Highlights

Aug 24, 2019
New Approach for Studying How Microbes Influence Their Environment
A diverse group of scientists suggests a common framework and targeting of known microbial processes [more...]

Aug 08, 2019
Nutrient-Hungry Peatland Microbes Reduce Carbon Loss Under Warmer Conditions
Enzyme production in peatlands reduces carbon lost to respiration under future high temperatures. [more...]

Aug 05, 2019
Amazon Forest Response to CO2 Fertilization Dependent on Plant Phosphorus Acquisition
AmazonFACE Model Intercomparison. The Science Plant growth is dependent on the availabi [more...]

Jul 29, 2019
A Slippery Slope: Soil Carbon Destabilization
Carbon gain or loss depends on the balance between competing biological, chemical, and physical reac [more...]

Jul 15, 2019
Field Evaluation of Gas Analyzers for Measuring Ecosystem Fluxes
How gas analyzer type and correction method impact measured fluxes. The Science A side- [more...]

List all highlights (possible long download time)