title: Metabolic versatility of toluene-degrading, iron-reducing bacteria in tidal flat sediment, characterized by stable isotope probing-based metagenomic analysis.
abstract: DNA stable isotope probing and metagenomic sequencing were used to assess the metabolic potential of iron-reducing bacteria involved in anaerobic aromatic hydrocarbon degradation in oil spill-affected tidal flats. In a microcosm experiment, (13) C-toluene was degraded with the simultaneous reduction of Fe(III)-NTA, which was also verified by quasi-stoichiometric (13) C-CO2 release. The metabolic potential of the dominant member affiliated with the genus Desulfuromonas in the heavy DNA fraction was inferred using assembled scaffolds (designated TF genome, 4.40 Mbp with 58.8 GC mol%), which were obtained by Illumina sequencing. The gene clusters with peripheral pathways for toluene and benzoate conversion possessed the features of strict and facultative anaerobes. In addition to the class II-type benzoyl-CoA reductase (Bam) of strict anaerobes, the class I-type (Bcr) of facultative anaerobes was encoded. Genes related to the utilization of various anaerobic electron acceptors, including iron, nitrate (to ammonia), sulfur and fumarate, were identified. Furthermore, genes encoding terminal oxidases (caa3 , cbb3 and bd) and a diverse array of genes for oxidative stress responses were detected in the TF genome. This metabolic versatility may be an adaptation to the fluctuating availability of electron acceptors and donors in tidal flats.
authors.affiliation: Department of Microbiology, Chungbuk National University, Cheongju, 361-763, Korea.
authors.forename: So-Jeong
authors.initials: SJ
authors.lastname: Kim
authors.forename: Soo-Je
authors.initials: SJ
authors.lastname: Park
authors.forename: In-Tae
authors.initials: IT
authors.lastname: Cha
authors.forename: Deullae
authors.initials: D
authors.lastname: Min
authors.forename: Jin-Seog
authors.initials: JS
authors.lastname: Kim
authors.forename: Won-Hyung
authors.initials: WH
authors.lastname: Chung
authors.forename: Jong-Chan
authors.initials: JC
authors.lastname: Chae
authors.forename: Che Ok
authors.initials: CO
authors.lastname: Jeon
authors.forename: Sung-Keun
authors.initials: SK
authors.lastname: Rhee
mesh_terms: D001419:Bacteria / Q000145:classification / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism; D001565:Benzoates / Q000378:metabolism; D001673:Biodegradation, Environmental; D002247:Carbon Isotopes / Q000378:metabolism; D019015:Geologic Sediments / Q000382:microbiology*; D007501:Iron / Q000378:metabolism*; D056186:Metagenomics; D044925:Oxidoreductases Acting on CH-CH Group Donors / Q000235:genetics / Q000378:metabolism; D010802:Phylogeny; D014050:Toluene / Q000737:chemistry / Q000378:metabolism*
chemical_list: D001426:Bacterial Proteins; D001565:Benzoates; D002247:Carbon Isotopes; D014050:Toluene; D007501:Iron; D044925:Oxidoreductases Acting on CH-CH Group Donors; C109030:benzoyl-coenzyme A reductase (dearomatizing)