title: Delta-proteobacterial SAR324 group in hydrothermal plumes on the South Mid-Atlantic Ridge.
abstract: In the dark ocean, the SAR324 group of Delta-proteobacteria has been associated with a chemolithotrophic lifestyle. However, their electron transport chain for energy generation and information system has not yet been well characterized. In the present study, four SAR324 draft genomes were extracted from metagenomes sampled from hydrothermal plumes in the South Mid-Atlantic Ridge. We describe novel electron transport chain components in the SAR324 group, particularly the alternative complex III, which is involved in energy generation. Moreover, we propose that the C-type cytochrome, for example the C553, may play a novel role in electron transfer, adding to our knowledge regarding the energy generation process in the SAR324 cluster. The central carbon metabolism in the described SAR324 genomes exhibits several new features other than methanotrophy e.g. aromatic compound degradation. This suggests that methane oxidation may not be the main central carbon metabolism component in SAR324 cluster bacteria. The reductive acetyl-CoA pathway may potentially be essential in carbon fixation due to the absence of components from the Calvin-Benson cycle. Our study provides insight into the role of recombination events in shaping the genome of the SAR324 group based on a larger number of repeat regions observed, which has been overlooked thus far.
authors.affiliation: Division of Life Science, The Hong Kong University of Science and Technology, Clear Water Bay, Hong Kong, China.
authors.forename: Huiluo
authors.initials: H
authors.lastname: Cao
authors.affiliation: Key Laboratory of Marine Biogenetic Resources, The Third Institute of Oceanography, State of Oceanic Administration, Xiamen, China.
authors.forename: Chunming
authors.initials: C
authors.lastname: Dong
authors.affiliation: Computational Bioscience Research Center (CBRC), King Abdullah University of Science and Technology (KAUST), Thuwal, Saudi Arabia.
authors.forename: Salim
authors.initials: S
authors.lastname: Bougouffa
authors.affiliation: State Key Laboratory of Marine Geology, Tongji University, Shanghai, China.
authors.forename: Jiangtao
authors.initials: J
authors.lastname: Li
authors.affiliation: Division of Life Science, The Hong Kong University of Science and Technology, Clear Water Bay, Hong Kong, China.
authors.forename: Weipeng
authors.initials: W
authors.lastname: Zhang
authors.affiliation: Key Laboratory of Marine Biogenetic Resources, The Third Institute of Oceanography, State of Oceanic Administration, Xiamen, China.
authors.forename: Zongze
authors.initials: Z
authors.lastname: Shao
authors.affiliation: Computational Bioscience Research Center (CBRC), King Abdullah University of Science and Technology (KAUST), Thuwal, Saudi Arabia.
authors.forename: Vladimir B
authors.initials: VB
authors.lastname: Bajic
authors.affiliation: Division of Life Science, The Hong Kong University of Science and Technology, Clear Water Bay, Hong Kong, China.
authors.forename: Pei-Yuan
authors.initials: PY
authors.lastname: Qian
mesh_terms: D001267:Atlantic Ocean; D001483:Base Sequence; D002633:Chemotaxis / Q000235:genetics / Q000502:physiology; D020564:Deltaproteobacteria / Q000145:classification / Q000235:genetics / Q000378:metabolism*; D014450:Electron Transport Complex III / Q000235:genetics*; D004734:Energy Metabolism / Q000235:genetics* / Q000502:physiology; D060086:Hydrothermal Vents / Q000382:microbiology*; D054892:Metagenome / Q000235:genetics; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D017422:Sequence Analysis, DNA
chemical_list: D012336:RNA, Ribosomal, 16S; D014450:Electron Transport Complex III