{"id":12242,"date":"2018-01-05T10:58:58","date_gmt":"2018-01-05T18:58:58","guid":{"rendered":"https:\/\/www.darkenergybiosphere.org\/?post_type=publication&#038;p=12242"},"modified":"2018-01-16T11:50:14","modified_gmt":"2018-01-16T19:50:14","slug":"homoacetogenesis-in-deep-sea-chloroflexi-as-inferred-by-single-cell-genomics-provides-a-link-to-reductive-dehalogenation-in-terrestrial-dehalococcoidetes","status":"publish","type":"publication","link":"https:\/\/www.darkenergybiosphere.org\/publication\/homoacetogenesis-in-deep-sea-chloroflexi-as-inferred-by-single-cell-genomics-provides-a-link-to-reductive-dehalogenation-in-terrestrial-dehalococcoidetes\/","title":{"rendered":"Homoacetogenesis in Deep-Sea Chloroflexi, as Inferred by Single-Cell Genomics, Provides a Link to Reductive Dehalogenation in Terrestrial Dehalococcoidetes"},"content":{"rendered":"<p>The deep marine subsurface is one of the largest unexplored biospheres on Earth and is widely inhabited by members of the phylum\u00a0<em>Chloroflexi<\/em>. In this report, we investigated genomes of single cells obtained from deep-sea sediments of the Peruvian Margin, which are enriched in such\u00a0<em>Chloroflexi<\/em>. 16S rRNA gene sequence analysis placed two of these single-cell-derived genomes (DscP3 and Dsc4) in a clade of subphylum I\u00a0<em>Chloroflexi<\/em>\u00a0which were previously recovered from deep-sea sediment in the Okinawa Trough and a third (DscP2-2) as a member of the previously reported DscP2 population from Peruvian Margin site 1230. The presence of genes encoding enzymes of a complete Wood-Ljungdahl pathway, glycolysis\/gluconeogenesis, a\u00a0<em>Rhodobacter<\/em>\u00a0nitrogen fixation (Rnf) complex, glyosyltransferases, and formate dehydrogenases in the single-cell genomes of DscP3 and Dsc4 and the presence of an NADH-dependent reduced ferredoxin:NADP oxidoreductase (Nfn) and Rnf in the genome of DscP2-2 imply a homoacetogenic lifestyle of these abundant marine\u00a0<em>Chloroflexi<\/em>. We also report here the first complete pathway for anaerobic benzoate oxidation to acetyl coenzyme A (CoA) in the phylum\u00a0<em>Chloroflexi<\/em>\u00a0(DscP3 and Dsc4), including a class I benzoyl-CoA reductase. Of remarkable evolutionary significance, we discovered a gene encoding a formate dehydrogenase (FdnI) with reciprocal closest identity to the formate dehydrogenase-like protein (complex iron-sulfur molybdoenzyme [CISM], DET0187) of terrestrial\u00a0<em>Dehalococcoides\/Dehalogenimonas<\/em>\u00a0spp. This formate dehydrogenase-like protein has been shown to lack formate dehydrogenase activity in\u00a0<em>Dehalococcoides\/Dehalogenimonas<\/em>\u00a0spp. and is instead hypothesized to couple HupL hydrogenase to a reductive dehalogenase in the catabolic reductive dehalogenation pathway. This finding of a close functional homologue provides an important missing link for understanding the origin and the metabolic core of terrestrial\u00a0<em>Dehalococcoides\/Dehalogenimonas<\/em>\u00a0spp. and of reductive dehalogenation, as well as the biology of abundant deep-sea\u00a0<em>Chloroflexi<\/em>.<\/p>\n","protected":false},"template":"","tags":[],"publication_type":[19],"_links":{"self":[{"href":"https:\/\/www.darkenergybiosphere.org\/wp-json\/wp\/v2\/publication\/12242"}],"collection":[{"href":"https:\/\/www.darkenergybiosphere.org\/wp-json\/wp\/v2\/publication"}],"about":[{"href":"https:\/\/www.darkenergybiosphere.org\/wp-json\/wp\/v2\/types\/publication"}],"wp:attachment":[{"href":"https:\/\/www.darkenergybiosphere.org\/wp-json\/wp\/v2\/media?parent=12242"}],"wp:term":[{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.darkenergybiosphere.org\/wp-json\/wp\/v2\/tags?post=12242"},{"taxonomy":"publication_type","embeddable":true,"href":"https:\/\/www.darkenergybiosphere.org\/wp-json\/wp\/v2\/publication_type?post=12242"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}