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Phototrophy and carbon fixation in Chlorobi postdate the rise of oxygen

While most productivity on the surface of the Earth today is fueled by oxygenic photosynthesis, for much of Earth history it is thought that anoxygenic photosynthesis—using compounds like ferrous iron or sulfide as electron donors—drove most global carbon fixation. Anoxygenic photosynthesis is still...

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Autores principales: Ward, L. M., Shih, Patrick M.
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Public Library of Science 2022
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9342728/
https://www.ncbi.nlm.nih.gov/pubmed/35913911
http://dx.doi.org/10.1371/journal.pone.0270187
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author Ward, L. M.
Shih, Patrick M.
author_facet Ward, L. M.
Shih, Patrick M.
author_sort Ward, L. M.
collection PubMed
description While most productivity on the surface of the Earth today is fueled by oxygenic photosynthesis, for much of Earth history it is thought that anoxygenic photosynthesis—using compounds like ferrous iron or sulfide as electron donors—drove most global carbon fixation. Anoxygenic photosynthesis is still performed by diverse bacteria in niche environments today. Of these, the Chlorobi (formerly green sulfur bacteria) are often interpreted as being particularly ancient and are frequently proposed to have fueled the biosphere during late Archean and early Paleoproterozoic time before the rise of oxygenic photosynthesis. Here, we perform comparative genomic, phylogenetic, and molecular clock analyses to determine the antiquity of the Chlorobi and their characteristic phenotypes. We show that contrary to common assumptions, the Chlorobi clade is relatively young, with anoxygenic phototrophy, carbon fixation via the rTCA pathway, and iron oxidation all significantly postdating the rise of oxygen ~2.3 billion years ago. The Chlorobi therefore could not have fueled the Archean biosphere, but instead represent a relatively young radiation of organisms which likely acquired the capacity for anoxygenic photosynthesis and other traits via horizontal gene transfer sometime after the evolution of oxygenic Cyanobacteria.
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spelling pubmed-93427282022-08-02 Phototrophy and carbon fixation in Chlorobi postdate the rise of oxygen Ward, L. M. Shih, Patrick M. PLoS One Research Article While most productivity on the surface of the Earth today is fueled by oxygenic photosynthesis, for much of Earth history it is thought that anoxygenic photosynthesis—using compounds like ferrous iron or sulfide as electron donors—drove most global carbon fixation. Anoxygenic photosynthesis is still performed by diverse bacteria in niche environments today. Of these, the Chlorobi (formerly green sulfur bacteria) are often interpreted as being particularly ancient and are frequently proposed to have fueled the biosphere during late Archean and early Paleoproterozoic time before the rise of oxygenic photosynthesis. Here, we perform comparative genomic, phylogenetic, and molecular clock analyses to determine the antiquity of the Chlorobi and their characteristic phenotypes. We show that contrary to common assumptions, the Chlorobi clade is relatively young, with anoxygenic phototrophy, carbon fixation via the rTCA pathway, and iron oxidation all significantly postdating the rise of oxygen ~2.3 billion years ago. The Chlorobi therefore could not have fueled the Archean biosphere, but instead represent a relatively young radiation of organisms which likely acquired the capacity for anoxygenic photosynthesis and other traits via horizontal gene transfer sometime after the evolution of oxygenic Cyanobacteria. Public Library of Science 2022-08-01 /pmc/articles/PMC9342728/ /pubmed/35913911 http://dx.doi.org/10.1371/journal.pone.0270187 Text en © 2022 Ward, Shih https://creativecommons.org/licenses/by/4.0/This is an open access article distributed under the terms of the Creative Commons Attribution License (https://creativecommons.org/licenses/by/4.0/) , which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
spellingShingle Research Article
Ward, L. M.
Shih, Patrick M.
Phototrophy and carbon fixation in Chlorobi postdate the rise of oxygen
title Phototrophy and carbon fixation in Chlorobi postdate the rise of oxygen
title_full Phototrophy and carbon fixation in Chlorobi postdate the rise of oxygen
title_fullStr Phototrophy and carbon fixation in Chlorobi postdate the rise of oxygen
title_full_unstemmed Phototrophy and carbon fixation in Chlorobi postdate the rise of oxygen
title_short Phototrophy and carbon fixation in Chlorobi postdate the rise of oxygen
title_sort phototrophy and carbon fixation in chlorobi postdate the rise of oxygen
topic Research Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9342728/
https://www.ncbi.nlm.nih.gov/pubmed/35913911
http://dx.doi.org/10.1371/journal.pone.0270187
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