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Proc Natl Acad Sci U S A. 2019 Mar 12;116(11):5037-5044. doi: 10.1073/pnas.1815631116. Epub 2019 Feb 27.

Hydrogenotrophic methanogenesis in archaeal phylum Verstraetearchaeota reveals the shared ancestry of all methanogens.

Author information

1
Department of Bioengineering, Stanford University, Stanford, CA 94305.
2
Chan Zuckerberg Biohub, San Francisco, CA 94158.
3
Department of Energy Joint Genome Institute, Walnut Creek, CA 94598.
4
Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139.
5
Broad Institute of Harvard and MIT, Cambridge, MA 02142.
6
Department of Bioengineering, Stanford University, Stanford, CA 94305; quake@stanford.edu.
7
Department of Applied Physics, Stanford University, Stanford, CA 94305.

Abstract

Methanogenic archaea are major contributors to the global carbon cycle and were long thought to belong exclusively to the euryarchaeal phylum. Discovery of the methanogenesis gene cluster methyl-coenzyme M reductase (Mcr) in the Bathyarchaeota, and thereafter the Verstraetearchaeota, led to a paradigm shift, pushing back the evolutionary origin of methanogenesis to predate that of the Euryarchaeota. The methylotrophic methanogenesis found in the non-Euryarchaota distinguished itself from the predominantly hydrogenotrophic methanogens found in euryarchaeal orders as the former do not couple methanogenesis to carbon fixation through the reductive acetyl-CoA [Wood-Ljungdahl pathway (WLP)], which was interpreted as evidence for independent evolution of the two methanogenesis pathways. Here, we report the discovery of a complete and divergent hydrogenotrophic methanogenesis pathway in a thermophilic order of the Verstraetearchaeota, which we have named Candidatus Methanohydrogenales, as well as the presence of the WLP in the crenarchaeal order Desulfurococcales. Our findings support the ancient origin of hydrogenotrophic methanogenesis, suggest that methylotrophic methanogenesis might be a later adaptation of specific orders, and provide insight into how the transition from hydrogenotrophic to methylotrophic methanogenesis might have occurred.

KEYWORDS:

archaea; evolution; methanogenesis

PMID:
30814220
PMCID:
PMC6421429
DOI:
10.1073/pnas.1815631116
[Indexed for MEDLINE]
Free PMC Article

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