title: Transfer of a Catabolic Pathway for Chloromethane in Methylobacterium Strains Highlights Different Limitations for Growth with Chloromethane or with Dichloromethane.
abstract: Chloromethane (CM) is an ozone-depleting gas, produced predominantly from natural sources, that provides an important carbon source for microbes capable of consuming it. CM catabolism has been difficult to study owing to the challenging genetics of its native microbial hosts. Since the pathways for CM catabolism show evidence of horizontal gene transfer, we reproduced this transfer process in the laboratory to generate new CM-catabolizing strains in tractable hosts. We demonstrate that six putative accessory genes improve CM catabolism, though heterologous expression of only one of the six is strictly necessary for growth on CM. In contrast to growth of Methylobacterium strains with the closely related compound dichloromethane (DCM), we find that chloride export does not limit growth on CM and, in general that the ability of a strain to grow on DCM is uncorrelated with its ability to grow on CM. This heterologous expression system allows us to investigate the components required for effective CM catabolism and the factors that limit effective catabolism after horizontal transfer.
authors.affiliation: Department of Biological Engineering, Massachusetts Institute of TechnologyCambridge, MA, USA; Department of Organismic and Evolutionary Biology, Harvard UniversityCambridge, MA, USA; Biosciences Division, Oak Ridge National LaboratoryOak Ridge, TN, USA.
authors.forename: Joshua K
authors.initials: JK
authors.lastname: Michener
authors.affiliation: UMR 7156 UNISTRA -CNRS, Université de Strasbourg Strasbourg, France.
authors.forename: Stéphane
authors.initials: S
authors.lastname: Vuilleumier
authors.affiliation: UMR 7156 UNISTRA -CNRS, Université de Strasbourg Strasbourg, France.
authors.forename: Françoise
authors.initials: F
authors.lastname: Bringel
authors.affiliation: Department of Organismic and Evolutionary Biology, Harvard UniversityCambridge, MA, USA; Department of Biological Sciences, University of IdahoMoscow, ID, USA; Institute for Bioinformatics and Evolutionary Studies, University of IdahoMoscow, ID, USA; Center for Modeling Complex Interactions, University of IdahoMoscow, ID, USA.
authors.forename: Christopher J
authors.initials: CJ
authors.lastname: Marx
keywords: Methylobacterium extorquens; bioremediation; chloromethane; horizontal gene transfer (HGT); microbial evolution