Editorial

Abstract

Multigene phylogeny and reclassification of yeasts and related filamentous taxa in Basidiomycota Basidiomycota are mainly known from mushroom-forming or plant pathogenic species, such as the agarics, smuts, bunts and rusts. However, all three subphyla of Basidiomycota, namely Agaricomycotina, Pucciniomycotina and Ustilaginomycotina, contain species that entirely or largely grow in a unicellular stage and that are known as basidiomycetous yeasts. The taxonomy of these basidiomycetous yeasts, however, has developed largely independent from that of the other taxa and was mainly based on physiological growth profiles, biochemical features of the cell wall, but also DNA features, such as molar percentage guanine and cytosine of the DNA, and molecular phylogenetic inferences. The taxonomy of the filamentous and mushroom-forming Basidiomycota was mainly based on morphology. However, in the era of molecular systematics and comparative genomics the taxonomies of these two “groups” of Basidiomycota can be unified. In this volume of Studies in Mycology we present phylogenies using multiple genes mainly of yeast taxa of Basidiomycota that we integrated with phylogenetic information from filamentous growing basidiomycetes, mainly sequence information of the D1D2 domains of the large subunit of the ribosomal DNA. As a result many so-called yeast or yeast-like species could be linked to filamentous growing species and an updated taxonomy is proposed accordingly. Several traditionally recognized genera of basidiomycetous yeasts were highly polyphyletic, e.g. Cryptococcus and Rhodotorula, just to name two. The multigene phylogenies made it possible to a large extent to redefine such polyphyletic genera. Monophyly was used as a leading principle with clustering optimization and the iterative application of a modified general mixed Yule coalescent (GMYC) as operational