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bioRxiv · 10.1101/527697

New Asgard archaea capable of anaerobic hydrocarbon cycling

Seitz, K. W.·Dombrowski, N.·Eme, L.·Spang, A.·Lombard, J.·Sieber, J. R.·Teske, A. P.·Ettma, T. J. G.·Baker, B. J.
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Abstract

Large reservoirs of natural gas in the oceanic subsurface sustain a complex biosphere of anaerobic microbes, including recently characterized archaeal lineages that extend the potential to mediate hydrocarbon oxidation (methane and butane) beyond the Methanomicrobia. Here we describe a new archaeal phylum, Helarchaeota, belonging to the Asgard superphylum with the potential for hydrocarbon oxidation. We reconstructed Helarchaeota genomes from hydrothermal deep-sea sediment metagenomes in hydrocarbon-rich Guaymas Basin, and show that these encode novel methyl-CoM reductase-like enzymes that are similar to those found in butane-oxidizing archaea. Based on these results as well as the presence of several alkyl-CoA oxidation and Wood-Ljungdahl pathway genes in the Helarchaeota genomes, we suggest that members of the Helarchaeota have the potential to activate and subsequently anaerobically oxidize short-chain hydrocarbons. These findings link a new phylum of Asgard archaea to the microbial utilization of hydrothermally generated hydrocarbons, and extend this genomic blueprint further through the archaeal domain.

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Seitz, K. W., Dombrowski, N., Eme, L., Spang, A., Lombard, J., Sieber, J. R., Teske, A. P., Ettma, T. J. G., Baker, B. J.. 2019-01-23. New Asgard archaea capable of anaerobic hydrocarbon cycling. https://doi.org/10.1101/527697

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