The Great Oxidation Event expanded the genetic repertoire of arsenic metabolism and cycling
The rise of oxygen on the early Earth about 2.4 billion years ago reorganized the redox cycle of harmful metal(loids), including that of arsenic, which doubtlessly imposed substantial barriers to the physiology and diversification of life. Evaluating the adaptive biological responses to these enviro...
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Published in | Proceedings of the National Academy of Sciences - PNAS Vol. 117; no. 19; pp. 10414 - 10421 |
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Main Authors | , , , , , , , , , , , |
Format | Journal Article |
Language | English |
Published |
United States
National Academy of Sciences
12.05.2020
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Subjects | |
Online Access | Get full text |
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Summary: | The rise of oxygen on the early Earth about 2.4 billion years ago reorganized the redox cycle of harmful metal(loids), including that of arsenic, which doubtlessly imposed substantial barriers to the physiology and diversification of life. Evaluating the adaptive biological responses to these environmental challenges is inherently difficult because of the paucity of fossil records. Here we applied molecular clock analyses to 13 gene families participating in principal pathways of arsenic resistance and cycling, to explore the nature of early arsenic biogeocycles and decipher feedbacks associated with planetary oxygenation. Our results reveal the advent of nascent arsenic resistance systems under the anoxic environment predating the Great Oxidation Event (GOE), with the primary function of detoxifying reduced arsenic compounds that were abundant in Archean environments. To cope with the increased toxicity of oxidized arsenic species that occurred as oxygen built up in Earth’s atmosphere, we found that parts of preexisting detoxification systems for trivalent arsenicals were merged with newly emerged pathways that originated via convergent evolution. Further expansion of arsenic resistance systems was made feasible by incorporation of oxygen-dependent enzymatic pathways into the detoxification network. These genetic innovations, together with adaptive responses to other redox-sensitive metals, provided organisms with novel mechanisms for adaption to changes in global biogeocycles that emerged as a consequence of the GOE. |
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Bibliography: | ObjectType-Article-1 SourceType-Scholarly Journals-1 ObjectType-Feature-2 content type line 23 Edited by Donald E. Canfield, Institute of Biology and Nordic Center for Earth Evolution (NordCEE), University of Southern Denmark, Odense M., Denmark, and approved March 20, 2020 (received for review January 25, 2020) 1 S.-C.C. and G.-X.S. contributed equally to this work. Author contributions: B.P.R. and Y.-G.Z. designed research; S.-C.C., G.-X.S., X.-M.L., and H.-L.C. performed research; S.-C.C., Y.Y., K.T.K., S.-Y.Z., Y.D., and D.P. analyzed data; and S.-C.C., G.-X.S., Y.Y., F.M., B.P.R., and Y.-G.Z. wrote the paper. |
ISSN: | 0027-8424 1091-6490 |
DOI: | 10.1073/pnas.2001063117 |