Impact of the Changes on Fungal Nomenclature to Ascomycetous Yeasts (#175)
Advances in molecular biology lead to enormous improvements in fungal taxonomy. Multigene phylogenies have been instrumental in the revision of the classification of ascosporic (telemorph) yeasts resulting in a natural system based on lines of decent. This has not yet been done for the anascoporic genus Candida, where it is increasingly disappointing to use the same generic name for yeast that have their nearest teleomorphic relatives classified in different families, discrediting all members of the genus Candida as potential human pathogens and concealing already known biological information. Generic names should communicate key-knowledge about related species groups. The problem is compounded by the new nomenclature rules reflecting the principle of one fungus = one name. To achieve this principle the current meaning of the name Candida = missing of ascospores could be replaced by information on metabolism, lifestyle and phylogenetic relationships if such criteria were integrated in a phylogenetic genus circumscription. Reclassification of Candida species by multigene phylogeny can be easily done in well-circumscribed sizable phylogenetic clades allow for the assignment of certain Candida species to existing teleomorphic genera with high confidence by multigene phylogeny. Candida species that form well-circumscribed sizable multigene phylogenetic clades without any teleomorphic members can become the base for new genera. Phylogenetically isolated species forming long branches in multigene phylogenies, could either be reclassified in small new genera or assigned to the most closely related teleomorph genus. Both options are unsatisfactory as they would results either in many small genera or the addition of distantly related species to homogeneous genera. As such, they should be maintained in the genus Candida until neighboring species are described to allow them being integrated in multigene analysis and the resulting groups have gained real biological meaning. When adapting the new nomenclature rules two principles should be followed: 1) Name stability should be honored to the largest possible extend, and 2) Great care should be taken not to create unnecessary names.