Alpha- and gammaproteobacterial methanotrophs codominate the active methane-oxidizing communities in an acidic boreal peat bog

Esson, Kaitlin C., Lin, Xueju, Kumaresan, Deepak, Chanton, Jeffrey P., Murrell, J. Colin and Kostka, Joel E. (2016) Alpha- and gammaproteobacterial methanotrophs codominate the active methane-oxidizing communities in an acidic boreal peat bog. Applied and Environmental Microbiology, 82 (8). pp. 2363-2371. ISSN 0099-2240

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Abstract

The objective of this study was to characterize metabolically active, aerobic methanotrophs in an ombrotrophic peatland in the Marcell Experimental Forest, Minnesota, USA. Methanotrophs were investigated in the field and in laboratory incubations using DNA-stable isotope probing, expression studies on particulate methane monooxygenase (pmoA) genes, and amplicon sequencing of 16S rRNA genes. Potential rates of oxidation ranged from 14-17 μmol CH4 g dry wt soil-1 d-1. Within DNA-SIP incubations, the relative abundance of methanotrophs increased from 4% in situ to 25-36% after 8 -14 days. Phylogenetic analysis of the 13C-enriched DNA fractions revealed the active methanotrophs were dominated by the genera Methylocystis (Type II; Alphaproteobacteria), Methylomonas, and Methylovulum (Type I; Gammaproteobacteria). In field samples, a transcript-to-gene ratio of 1 to 2 was observed for pmoA in surface peat layers which attenuated rapidly with depth, indicating the highest methane consumption was associated with the 0-10 cm depth interval. Metagenomes and sequencing of cDNA pmoA amplicons from field samples confirmed the dominant active methanotrophs were Methylocystis and Methylomonas. Although Type II methanotrophs have long been shown to mediate methane consumption in peatlands, our results indicate members of the genera Methylomonas and Methylovulum (Type I) can significantly contribute to aerobic methane oxidation in these ecosystems.

Item Type:	Article
Faculty \ School:	Faculty of Science > School of Environmental Sciences University of East Anglia Research Groups/Centres > Theme - ClimateUEA
UEA Research Groups:	Faculty of Science > Research Groups > Environmental Biology Faculty of Science > Research Centres > Centre for Ecology, Evolution and Conservation
Depositing User:	Pure Connector
Date Deposited:	22 Mar 2016 09:38
Last Modified:	31 Oct 2023 01:46
URI:	https://ueaeprints.uea.ac.uk/id/eprint/57830
DOI:	10.1128/AEM.03640-15

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