Molecular characterization of red yeasts from aquatic environments in Patagonia, Argentina

LIBKIND FRATI, D; BRIZZIO, S; RUFFINI, A; GADANHO, M; VAN BROOCK, MR; SAMPAIO, JP

Oslo, Noruega

Congreso; 7th International Mycological Conference; 2002

Main features of aquatic environments of glacial origin in Patagonia (Argentina) are low pollution level and ultraoligotrophy. Eight of these aquatic reservoirs were surveyed for the occurrence of red yeasts. Subsurface water samples were filtered and used for colony counting and yeast isolation. A set of 64 isolates was characterised based on the mini/micro satellite-primed technique (MSP-PCR). DNA fingerprinting with M13 and (GTG)5 primers allowed the grouping of 34% and 56% of all isolates, respectively. Comparison of representative fingerprints of each group with those of type strains of various pigmented yeast, made possible the quick identification of an 87% of isolates. The 26S rDNA (D1/D2 domain) sequence analysis was performed for one representative of the remaining unidentified groups. Rhodotorula mucilaginosa was found in almost all samples and represented ca. 50% of the isolates studied. Less frequent species corresponded to 6 genera and 16 species including five new yeast species of the genera Rhodotorula (2), Cryptococcus (1) and Sporobolomyces (2). Total yeast counting usually ranged 1-150 CFU l-1 and rarely exceeded 200 CFU l-1. In contrast with other studies on yeast biodiversity in freshwater, red yeasts did not often predominated in our water samples. This study represents the first report on red yeast occurrence and biodiversity in North-western Patagonia.