Biodiversity of cold tolerant yeasts from subglacial environments in Patagonia Argentina

DE GARCÍA VIRGINIA; BRIZZIO SILVIA; LIBKIND DIEGO; BUZZINI PIETRO; VAN BROOCK MARÍA

Innsbruck

Congreso; International Conference on Alpine and Polar Microbiology; 2006

Although studies on microbial diversity of cold environments have focused mainly on bacteria, occurrence of filamentous fungi and yeasts is also well documented in different substrates in Antarctic, Arctic and Alpine ecosystems. Patagonian Andes in Southwestern Argentina offer interesting and unexplored glacial environments, which arise as possible reservoirs of cold-adapted yeasts. MountTronador (3.554 m.a.s.l.) is located 71º 50` W and 41º 10` S in Chile – Argentina border. Four of its ten ice tongues are situated within Nahuel Huapi National Park (NHNP). Occurrence of yeasts in rivers draining from three glaciers (Frías, Castaño Overo and Río Manso) has been studied for the first time and is reported here. After filtration of the samples and incubation of the filters at 4 – 15 ºC in MYP agar for up to 1 month, more than 100 strains were isolated. All of them were identified up to genus level by biochemical and molecular techniques. Basidiomicetous yeasts represented 88 % of the isolates. Cryptococcus, Leucosporidiella, Dioszegia, Rhodotorula, Tremella, Mrakia, Sporobolomyces, Bullera, Udeniomyces and Candida genera were found. The former was the most frequently isolated species in all samples (47 % of the total strains), while Leucosporidiella accounted for 16 %, although it was isolated only from Frías glacier. From sixteen species identified, Cr. laurentii, Cr. terreus and L. fragaria were the most representative ones. These results are in agreement with reports on yeast diversity from Antarctic and Alpine glacial environments. Several isolates differed significantly from those species already known and might probably represent undescribed species.