title: Metagenomic analysis reveals the contribution of anaerobic methanotroph-1b in the oxidation of methane at the Ulleung Basin, East Sea of Korea.
abstract: We have previously identified a sulfate methane transition zone (SMTZ) within the methane hydrate-bearing sediment in the Ulleung Basin, East Sea of Korea, and the presence of ANME-1b group in the sediment has been shown by phylogenetic analysis of a 16S rRNA gene. Herein, we describe taxonomic and functional profiling in the SMTZ sample by metagenomic analysis, comparing with that of surface sediment. Metagenomic sequences of 115 Mbp and 252 Mbp were obtained from SMTZ and surface sediments, respectively. The taxonomic profiling using BLASTX against the SEED within MG-RAST showed the prevalence of methanogens (19.1%), such as Methanosarcinales (12.0%) and Methanomicrobiales (4.1%) predominated within the SMTZ metagenome. A number of 185,200 SMTZ reads (38.9%) and 438,484 surface reads (62.5%) were assigned to functional categories, and methanogenesis-related reads were statistically significantly overrepresented in the SMTZ metagenome. However, the mapping analysis of metagenome reads to the reference genomes, most of the sequences of the SMTZ metagenome were mapped to ANME-1 draft genomes, rather than those of methanogens. Furthermore, the two copies of the methyl-coenzyme M reductase gene (mcrA) segments of the SMTZ metagenome were clustered with ANME-1b in the phylogenetic cluster. These results indicate that ANME-1b reads were miss-annotated to methanogens due to limitation of database. Many of key genes necessary for reverse methanogenesis were present in the SMTZ metagenome, except for N5,N10-methenyl-H4MPT reductase (mer) and CoB-CoM heterodisulfide reductase subunits D and E (hdrDE). These data suggest that the ANME-1b represents the primary player the anaerobic methane oxidation in the SMTZ, of the methane hydrate-bearing sediment at the Ulleung Basin, East Sea of Korea.
authors.affiliation: Marine Biotechnology Research Division, Korea Institute of Ocean Science and Technology, Ansan, 15627, Republic of Korea.|Department of Microbiology, Chungbuk National University, Cheongju, 28644, Republic of Korea.
authors.forename: Jin-Woo
authors.initials: JW
authors.lastname: Lee
authors.affiliation: Marine Biotechnology Research Division, Korea Institute of Ocean Science and Technology, Ansan, 15627, Republic of Korea.
authors.forename: Kae Kyoung
authors.initials: KK
authors.lastname: Kwon
authors.affiliation: Petroleum and Marine Resources Research Division, Korea Institute of Geoscience and Mineral Resources, Daejeon, 34132, Republic of Korea.
authors.forename: Jang-Jun
authors.initials: JJ
authors.lastname: Bahk
authors.affiliation: Department of Microbiology, Chungbuk National University, Cheongju, 28644, Republic of Korea.
authors.forename: Dong-Hun
authors.initials: DH
authors.lastname: Lee
authors.affiliation: Marine Biotechnology Research Division, Korea Institute of Ocean Science and Technology, Ansan, 15627, Republic of Korea.
authors.forename: Hyun Sook
authors.initials: HS
authors.lastname: Lee
authors.affiliation: Marine Biotechnology Research Division, Korea Institute of Ocean Science and Technology, Ansan, 15627, Republic of Korea.
authors.forename: Sung Gyun
authors.initials: SG
authors.lastname: Kang
authors.affiliation: Marine Biotechnology Research Division, Korea Institute of Ocean Science and Technology, Ansan, 15627, Republic of Korea. jlee@kiost.ac.
authors.forename: Jung-Hyun
authors.initials: JH
authors.lastname: Lee
mesh_terms: D000693:Anaerobiosis; D001105:Archaea / Q000145:classification / Q000235:genetics* / Q000302:isolation & purification; D019641:DNA, Archaeal / Q000235:genetics; D019605:Euryarchaeota / Q000145:classification / Q000235:genetics* / Q000302:isolation & purification / Q000378:metabolism*; D019015:Geologic Sediments / Q000382:microbiology; D054892:Metagenome; D056186:Metagenomics; D008697:Methane / Q000378:metabolism*; D017018:Methanomicrobiales / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism; D019640:Methanosarcinales / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism; D009792:Oceans and Seas; D010084:Oxidation-Reduction; D010802:Phylogeny; D012336:RNA, Ribosomal, 16S; D056910:Republic of Korea
chemical_list: D019641:DNA, Archaeal; D012336:RNA, Ribosomal, 16S; D008697:Methane
keywords: anaerobic methanotroph-1b (ANME-1b); metagenomics; reverse methanogenesis pathway; sulfate methane transition zone (SMTZ)