title: Detection and isolation of chloromethane-degrading bacteria from the Arabidopsis thaliana phyllosphere, and characterization of chloromethane utilization genes.
abstract: Chloromethane gas is produced naturally in the phyllosphere, the compartment defined as the aboveground parts of vegetation, which hosts a rich bacterial flora. Chloromethane may serve as a growth substrate for specialized aerobic methylotrophic bacteria, which have been isolated from soil and water environments, and use cmu genes for chloromethane utilization. Evidence for the presence of chloromethane-degrading bacteria on the leaf surfaces of Arabidopsis thaliana was obtained by specific quantitative PCR of the cmuA gene encoding the two-domain methyltransferase corrinoid protein of chloromethane dehalogenase. Bacterial strains were isolated on a solid mineral medium with chloromethane as the sole carbon source from liquid mineral medium enrichment cultures inoculated with leaves of A. thaliana. Restriction analysis-based genotyping of cmuA PCR products was used to evaluate the diversity of chloromethane-degrading bacteria during enrichment and after strain isolation. The isolates obtained, affiliated to the genus Hyphomicrobium based on their 16S rRNA gene sequence and the presence of characteristic hyphae, dehalogenate chloromethane, and grow in a liquid culture with chloromethane as the sole carbon and energy source. The cmu genes of these isolates were analysed using new PCR primers, and their sequences were compared with those of previously reported aerobic chloromethane-degrading strains. The three isolates featured a colinear cmuBCA gene arrangement similar to that of all previously characterized strains, except Methylobacterium extorquens CM4 of known genome sequence.
authors.affiliation: Université de Strasbourg, UMR 7156 CNRS, Strasbourg, France. nadalig@unistra.fr
authors.forename: Thierry
authors.initials: T
authors.lastname: Nadalig
authors.forename: Muhammad
authors.initials: M
authors.lastname: Farhan Ul Haque
authors.forename: Sandro
authors.initials: S
authors.lastname: Roselli
authors.forename: Hubert
authors.initials: H
authors.lastname: Schaller
authors.forename: Françoise
authors.initials: F
authors.lastname: Bringel
authors.forename: Stéphane
authors.initials: S
authors.lastname: Vuilleumier
mesh_terms: D017360:Arabidopsis / Q000382:microbiology*; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism; D004269:DNA, Bacterial / Q000235:genetics; D005798:Genes, Bacterial; D005838:Genotype; D020582:Hyphomicrobium / Q000145:classification / Q000235:genetics / Q000302:isolation & purification* / Q000378:metabolism; D008737:Methyl Chloride / Q000378:metabolism*; D008780:Methyltransferases / Q000235:genetics* / Q000378:metabolism; D010802:Phylogeny; D018515:Plant Leaves / Q000382:microbiology; D016133:Polymerase Chain Reaction; D012150:Polymorphism, Restriction Fragment Length; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D017422:Sequence Analysis, DNA
chemical_list: D001426:Bacterial Proteins; D004269:DNA, Bacterial; D012336:RNA, Ribosomal, 16S; D008737:Methyl Chloride; D008780:Methyltransferases