RRC ID 74026
Author Tamre E, Fournier GP.
Title Inferred ancestry of scytonemin biosynthesis proteins in cyanobacteria indicates a response to Paleoproterozoic oxygenation.
Journal Geobiology
Abstract Protection from radiation damage is an important adaptation for phototrophic microbes. Living in surface, shallow water, and peritidal environments, cyanobacteria are especially exposed to long-wavelength ultraviolet (UVA) radiation. Several groups of cyanobacteria within these environments are protected from UVA damage by the production of the pigment scytonemin. Paleontological evidence of cyanobacteria in UVA-exposed environments from the Proterozoic, and possibly as early as the Archaean, suggests a long evolutionary history of radiation protection within this group. We show that phylogenetic analyses of enzymes in the scytonemin biosynthesis pathway support this hypothesis and reveal a deep history of vertical inheritance of this pathway within extant cyanobacterial diversity. Referencing this phylogeny to cyanobacterial molecular clocks suggests that scytonemin production likely appeared during the early Proterozoic, soon after the Great Oxygenation Event. This timing is consistent with an adaptive scenario for the evolution of scytonemin production, wherein the threat of UVA-generated reactive oxygen species becomes significantly greater once molecular oxygen is more pervasive across photosynthetic environments.
Volume 20(6)
Pages 764-775
Published 2022-11-1
DOI 10.1111/gbi.12514
PMID 35851984
PMC PMC9796282
MeSH Cyanobacteria* / metabolism Indoles Oxygen / metabolism Phenols Phylogeny Reactive Oxygen Species / metabolism Water / metabolism
Algae NIES-21 NIES-23 NIES-25 NIES-26 NIES-267 NIES-2108 NIES-2111 NIES-3756 NIES-4073 NIES-4074 NIES-4075 NIES-4103