UV-resistant actinobacteria from High-Altitude Andean Lakes: Biodiversity and adaptation mechanisms

ALBARRACÍN V. H.; FARIAS, M.E.; PORTERO, L.R.; ZANNIER, F.

Pisa

Congreso; 17TH CONGRESS OF THE EUROPEAN SOCIETY FOR PHOTOBIOLOGY; 2017

Ultraviolet radiation can damage biomolecules, with detrimental or even lethal effects for life. Even though lower wavelengths are filtered by the ozone layer, a significant amount of harmful UV-B and UV-A radiation reach Earth?s surface, particularly in high altitude environments. High-Altitude Andean Lakes (HAAL) are a group of disperse shallow lakes and salterns, located at the Dry Central Andes region in South America at altitudes above 3,000 m, described as one of the highest UV-exposed environments. Thus, HAAL`s microbes constitute model systems to study UV-resistance mechanisms in environmental bacteria at various complexity levels. Herein, we present a high diversity of UV-resistant actinobacteria isolated from soils, water, sediments and modern stromatolites and described molecular mechanisms involved in the UV-resistome of the model strain Nesterenkonia sp. Act20. Using genomic and proteomic analysis, an ?UV-resistome? for Act20 was defined including the following components: i) cryptochrome/photolyase related genes that may function as UV-photoreceptor and in DNA repair; ii) special genes coding for UV-absorbing pigments; iii) a standard set of genes related to oxidative damage and ROS scavenging was found (catalase, SOD). iv) tolerance systems to DNA, protein and lipid damages. Our results help to unravel the UV-resistance mechanism of HAAL´s microbes. Genomics and proteomic findings support previous work describing high UV-resistance profile in Act20, and suggest new targets for further characterization, which might be involved in regulation and resistance to damage.