Yeast photoprotection and community structure under UV radiation

LIBKIND, DIEGO; MOLINÉ, MARTÍN; MUÑOZ, MARIO IVÁN; VAN BROOCK, MARÍA

Madison, Winsconsin

Congreso; ICY (International Commission on Yeast) 2012; 2012

ICY (International Commission on Yeast)

Ultraviolet radiation (UVR) is recognized as a strong selective force and UVR levels that are considered normal have significant impacts on natural ecosystems. Yeasts inhabit almost all type of natural habitats even those considered extreme, though little is actually known about the significance of UVR in shaping natural yeast communities. Here we review our data on natural yeast populations from Patagonia (Argentina) exposed to different UVR fluxes (aquatic environments, phylloplane, and soil) and the relationship between the ability to synthesize photoprotective compounds like antioxidants (carotenoids) and UV sunscreen (mycosporines) and UVR tolerance. Yeasts able to accumulate at least one of these metabolites were found to prevail in highly exposed habitats. We performed in vivo and in vitro studies with representative carotenoids and the mycosporine: mycosporine-glutaminol-glucoside, demonstrating their value as photoprotective compounds in yeasts. Cryptococcus steppossus, Rhodotorula mucilaginosa and Xanthophyllomyces dendrorhous (Phaffia rhodozyma) were used as main model species. Collectively, our work reveals that there is a relationship between the ability of yeasts to produce photoprotective compounds, their tolerance to UV exposure and their success in colonizing habitats highly exposed to UVR. Thus, we show the importance of UVR as selective force determining the yeast community structure in natural habitats.