Phylogenetic distribution of fungal mycosporines within the Pucciniomycotina (Basidiomycota)

The synthesis of the UV Absorbing compounds named mycosporines (MYCs) has been detected in a few basidiomycetous yeast groups. Conspicuous accumulation of mycosporine-glutaminol-glucoside (MGG) in yeasts requires photo-induction and its photoprotective function has been postulated. The distribution of the ability to produce MYCs appeared to be related to the yeast taxonomic affiliation. In view of the potential significance of MYCs in yeast taxonomy, we here studied the distribution of this trait among dimorphic basidiomycetes of the Pucciniomycotina. Of the 94 fungal species (377 strains and 33 genera) tested, almost half were MYC-positive and MGG was the main compound produced. MGG synthesis was observed for representatives of five of seven Pucciniomycotina classes, indicating that this trait is widely distributed in this group. MGG detection proved useful for the differentiation of species of the polyphyletic genera, such as Rhodotorula and Sporobolomyces, that are phylogenetically separated. MGG quantification and UV tolerance studies in Cystobasidiomycetes supported the idea that the habitat of origin of each strains is important in the level of MGG synthesis and that MYCs have a photoprotective function in yeasts. The taxonomic value of this trait in fungal systematics is discussed.