New Phaffia spp. strains associated with fruiting bodies of Cyttaria hariotii in Patagonia, Argentina

LIBKIND FRATI, D; SAMPAIO, JP; RUFFINI, A; VAN BROOCK, MR

Rio de Janeiro, Brasil

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

A biodiversity survey focused on pigmented yeast species present in Patagonian natural environments is being carried out. While studying yeast occurrence in high altitude aquatic environments two orange pigmented strains were isolated and characterized by physiological tests and Micro/Mini satellite primed PCR technique (MSP-PCR). MSP-PCR DNA fingerprints of these strains differed to those obtain for type strains but were identical to those displayed by 3 additional strains isolated from the fruit body of a parasitic fungi (Cyttaria sp.) of an patagonian endemic tree (Nothofagus sp.). D1/D2 sequence analysis of the rDNA showed no differences with the astaxanthin producing yeast  Xanthophyllomyces dendrhourus (Phaffia rhodozyma) strains and these strains had the ability to ferment glucose and other sugars (i.e. maltose, sucrose, trehalose and melezitose). ITS sequences were also studied, since high intraspecific variability has been reported for Xanthophyllomyces dendrhourus (Phaffia rhodozyma) which may indicate the existence of more than one species. Patagonian native strains ITS sequences were identical and differed by 17 nucleotide substitutions to its closest match, Phaffia rhodozyma (CBS 5905T) Type strain. No sexual structures could be observed in the Patagonian isolates when grown in sporulation medium while PYCC exhibited typical slender holobasidium. Geographic distribution, ecological specificity and complete ITS sequence data suggest these Patagonian isolates as representative of an undescribed species in the genus Phaffia. Complementary studies are presently under way to verify this hypothesis.