Mycosporines: yeast`s sunscreens?

LIBKIND, DIEGO; PEREZ, PATRICIA; SOMMARUGA, RUBÉN; DIEGUEZ, MARÍA DEL CARMEN; ZAGARESE, HORACIO; VAN BROOCK, MARÍA

RIO DE JANEIRO

Congreso; XI International Congress on Yeasts (ICY); 2004

Microbial synthesis of photoprotective compounds such as carotenoids pigments (antioxidant) and mycosporines (UV sunscreen) is one of the known strategies to minimize damage from UV radiation exposure. The production of mycosporines was first detected in filamentous ascomycetous fungi exposed to UV light, where sporulation induction appeared to be the main associated effect1. Recently, mycosporine synthesis was reported to occur in yeasts as well2. A number of basidiomycetous carotenoid-producing yeast strains grown under photosynthetically active radiation (PAR) synthesized a UV-absorbing compound showing a maximum absorption at 309-310 nm and identified as mycosporine-glutaminol-glucoside (MGG) by LC/MS/MS. A higher extent of mycosporine synthesis was observed when the cells were grown under PAR in combination with UV radiation. In this study, the ability to produce MGG in 150 (8 genera, 24 species) pigmented yeast strains from Patagonia (Argentina) was assessed. The strains belong to four taxonomic groups; 1) Order Sporidiobolales (Class Urediniomycetes), 2) Erythrobasidium clade (Class Urediniomycetes), 3) Order Cystofilobasidiales (Class Hymenomycetes), and 4) Tremellales order (Class Hymenomycetes). Induction of mycosporines did not occur in all pigmented yeast strains tested and it appeared to be a species related character on yeast members of the Erythrobasidium clade and the Tremellales. The UV-screening and antioxidant properties attributed to mycosporines suggest a probable photoprotective role of these compounds in nature. However, the occurrence of MGG in this yeast group could reflect phylogenetic relationships among species not strictly related to environmental factors. The production of mycosporines by yeasts represents an interesting subject of study due to its novelty and ecological and biotechnological impact. A wider screening study is being performed to prove mycosporine synthesis as a chemotaxonomical character to be use in yeast identification and systematics.