Polymorphism of viral dsRNA in Xanthophyllomyces dendrorhous strains isolated from different geographic areas

Abstract

Background. Strains of the astaxanthin producing yeast Xanthophyllomyces dendrorhous have been isolated from different cold regions around the earth, and the presence of double stranded RNA (dsRNA) elements was described in some isolates. This kind of viruses is widely distributed among yeasts and filamentous fungi and, although generally are cryptic in function, their studies have been a key factor in the knowledge of important fungi. In this work, the characterization and genetic relationships among dsRNA elements were determined in strains representatives of almost all regions of the earth where X. dendrorhous have been isolated. Results. Almost all strains of X. dendrorhous analyzed carry one, two or four dsRNA elements, of molecular sizes in the range from 0.8 to 5.0 kb. Different dsRNA-patterns were observed in strains with different geographic origin, being L1 (5.0 kb) the common dsRNA element. By hybridization assays a high genomic polymorphism was observed among L1 dsRNAs of d