Casero Chamorro, María CristinaAscaso, CarmenQuesada, AntonioMazur Marzec, HannaWierzchos, Jacek2026-01-202026-01-202021Casero MC, Ascaso C, Quesada A, Mazur-Marzec H and Wierzchos J (2021) Response of Endolithic Chroococcidiopsis Strains From the Polyextreme Atacama Desert to Light Radiation. Front. Microbiol. 11:614875. doi: 10.3389/fmicb.2020.6148751664-302X10.3389/fmicb.2020.614875https://hdl.handle.net/20.500.14352/130602This study was supported by grant PGC2018-094076-B-I00 from MCIU/AEI (Spain) and FEDER (UE). MC was supported by grant BES 2014-069106 from the Spanish Ministry of Science and Innovation (MCINN).Cyanobacteria exposed to high solar radiation make use of a series of defense mechanisms, including avoidance, antioxidant systems, and the production of photoprotective compounds such as scytonemin. Two cyanobacterial strains of the genus Chroococcidiopsis from the Atacama Desert – which has one of the highest solar radiation levels on Earth- were examined to determine their capacity to protect themselves from direct photosynthetically active (PAR) and ultraviolet radiation (UVR): the UAM813 strain, originally isolated from a cryptoendolithic microhabitat within halite (NaCl), and UAM816 strain originally isolated from a chasmoendolithic microhabitat within calcite (CaCO3). The oxidative stress induced by exposure to PAR or UVR + PAR was determined to observe their short-term response, as were the long-term scytonemin production, changes in metabolic activity and ultrastructural damage induced. Both strains showed oxidative stress to both types of light radiation. The UAM813 strain showed a lower acclimation capacity than the UAM816 strain, showing an ever-increasing accumulation of reactive oxygen species (ROS) and a smaller accumulation of scytonemin. This would appear to reflect differences in the adaptation strategies followed to meet the demands of their different microhabitats.engAttribution 4.0 Internationalhttp://creativecommons.org/licenses/by/4.0/journal articlehttps://doi.org/10.3389/fmicb.2020.614875https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2020.614875/fullopen access582.232579.26574.2577.34ChroococcidiopsisEndolithicAtacamaLightScytoneminMicrobiología (Biología)Ecología (Biología)Biología celular (Biología)2414 Microbiología2302.20 Química Microbiológica2407 Biología Celular