title: Single-cell and metagenomic analyses indicate a fermentative and saccharolytic lifestyle for members of the OP9 lineage.
abstract: OP9 is a yet-uncultivated bacterial lineage found in geothermal systems, petroleum reservoirs, anaerobic digesters and wastewater treatment facilities. Here we use single-cell and metagenome sequencing to obtain two distinct, nearly complete OP9 genomes, one constructed from single cells sorted from hot spring sediments and the other derived from binned metagenomic contigs from an in situ-enriched cellulolytic, thermophilic community. Phylogenomic analyses support the designation of OP9 as a candidate phylum for which we propose the name 'Atribacteria'. Although a plurality of predicted proteins is most similar to those from Firmicutes, the presence of key genes suggests a diderm cell envelope. Metabolic reconstruction from the core genome suggests an anaerobic lifestyle based on sugar fermentation by Embden-Meyerhof glycolysis with production of hydrogen, acetate and ethanol. Putative glycohydrolases and an endoglucanase may enable catabolism of (hemi)cellulose in thermal environments. This study lays a foundation for understanding the physiology and ecological role of the 'Atribacteria'.
authors.affiliation: School of Life Sciences, University of Nevada, Las Vegas, Las Vegas, Nevada 89154-4004, USA.
authors.forename: Jeremy A
authors.initials: JA
authors.lastname: Dodsworth
authors.forename: Paul C
authors.initials: PC
authors.lastname: Blainey
authors.forename: Senthil K
authors.initials: SK
authors.lastname: Murugapiran
authors.forename: Wesley D
authors.initials: WD
authors.lastname: Swingley
authors.forename: Christian A
authors.initials: CA
authors.lastname: Ross
authors.forename: Susannah G
authors.initials: SG
authors.lastname: Tringe
authors.forename: Patrick S G
authors.initials: PS
authors.lastname: Chain
authors.forename: Matthew B
authors.initials: MB
authors.lastname: Scholz
authors.forename: Chien-Chi
authors.initials: CC
authors.lastname: Lo
authors.forename: Jason
authors.initials: J
authors.lastname: Raymond
authors.forename: Stephen R
authors.initials: SR
authors.lastname: Quake
authors.forename: Brian P
authors.initials: BP
authors.lastname: Hedlund
mesh_terms: D001419:Bacteria / Q000166:cytology* / Q000235:genetics*; D002462:Cell Membrane / Q000378:metabolism; D002482:Cellulose / Q000378:metabolism*; D004734:Energy Metabolism; D005285:Fermentation; D054892:Metagenome / Q000235:genetics; D056186:Metagenomics / Q000379:methods*; D008969:Molecular Sequence Data; D010802:Phylogeny; D025341:Principal Component Analysis; D059010:Single-Cell Analysis / Q000379:methods*
chemical_list: D002482:Cellulose