title: Genomic composition and dynamics among Methanomicrobiales predict adaptation to contrasting environments.
abstract: Members of the order Methanomicrobiales are abundant, and sometimes dominant, hydrogenotrophic (H2-CO2utilizing) methanoarchaea in a broad range of anoxic habitats. Despite their key roles in greenhouse gas emissions and waste conversion to methane, little is known about the physiological and genomic bases for their widespread distribution and abundance. In this study, we compared the genomes of nine diverse Methanomicrobiales strains, examined their pangenomes, reconstructed gene flow and identified genes putatively mediating their success across different habitats. Most strains slowly increased gene content whereas one, Methanocorpusculum labreanum, evidenced genome downsizing. Peat-dwelling Methanomicrobiales showed adaptations centered on improved transport of scarce inorganic nutrients and likely use H+rather than Na+transmembrane chemiosmotic gradients during energy conservation. In contrast, other Methanomicrobiales show the potential to concurrently use Na+and H+chemiosmotic gradients. Analyses also revealed that the Methanomicrobiales lack a canonical electron bifurcation system (MvhABGD) known to produce low potential electrons in other orders of hydrogenotrophic methanogens. Additional putative differences in anabolic metabolism suggest that the dynamics of interspecies electron transfer from Methanomicrobiales syntrophic partners can also differ considerably. Altogether, these findings suggest profound differences in electron trafficking in the Methanomicrobiales compared with other hydrogenotrophs, and warrant further functional evaluations.
authors.affiliation: School of Life Sciences, Arizona State University, Tempe, AZ, USA.
authors.forename: Patrick
authors.initials: P
authors.lastname: Browne
authors.affiliation: Bioproduction Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), Ibaraki, Japan.
authors.forename: Hideyuki
authors.initials: H
authors.lastname: Tamaki
authors.affiliation: Department of Energy, Joint Genome Institute, Walnut Creek, CA, USA.
authors.forename: Nikos
authors.initials: N
authors.lastname: Kyrpides
authors.affiliation: Department of Energy, Joint Genome Institute, Walnut Creek, CA, USA.
authors.forename: Tanja
authors.initials: T
authors.lastname: Woyke
authors.affiliation: Los Alamos National Laboratory, Los Alamos, NM, USA.
authors.forename: Lynne
authors.initials: L
authors.lastname: Goodwin
authors.affiliation: Department of Subsurface Geobiological Analysis and Research, Japan Agency for Marine-Earth Science and Technology, Yokosuka, Kanagawa, Japan.
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Imachi
authors.affiliation: Department of Biology, Appalachian State University, Boone, NC, USA.
authors.forename: Suzanna
authors.initials: S
authors.lastname: Bräuer
authors.affiliation: Department of Natural Resources, Cornell University, Ithaca, NY, USA.
authors.forename: Joseph B
authors.initials: JB
authors.lastname: Yavitt
authors.affiliation: Department of Civil and Environmental Engineering, University of Illinois at Urbana-Champaign, Urbana, IL, USA.
authors.forename: Wen-Tso
authors.initials: WT
authors.lastname: Liu
authors.affiliation: Department of Microbiology, Cornell University, Ithaca, NY, USA.
authors.forename: Stephen
authors.initials: S
authors.lastname: Zinder
authors.affiliation: School of Life Sciences, Arizona State University, Tempe, AZ, USA.|Swette Center for Environmental Biotechnology at the Biodesign Institute, Arizona State University, Tempe, AZ, USA.
authors.forename: Hinsby
authors.initials: H
authors.lastname: Cadillo-Quiroz
mesh_terms: D000064:Acclimatization; D000222:Adaptation, Physiological; D017753:Ecosystem; D020745:Genome, Archaeal; D023281:Genomics; D008697:Methane / Q000378:metabolism; D017018:Methanomicrobiales / Q000145:classification / Q000235:genetics* / Q000302:isolation & purification / Q000502:physiology; D010802:Phylogeny; D012987:Soil; D012988:Soil Microbiology
chemical_list: D012987:Soil; D008697:Methane