Submitted to: Antonie Van Leeuwenhoek
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/21/2003
Publication Date: 2/1/2004
Citation: Kurtzman, C.P. 2004. Trichomonascus petasosporus sp. nov. and Sympodiomyces indianaensis sp. nov., two new members of the Saccharomycetales. Antonie Van Leeuwenhoek. 85:297-204. Interpretive Summary: Yeast classification was formerly based exclusively on morphology and the apparent uniqueness of certain physiological properties. Gene sequence analyses have shown that morphology and physiology are often poor predictors of relatedness. In the present study, a unique fungus was discovered, that from morphology, might be classified among the "higher ascomycetes" (euascomycetes). On the basis of gene sequence analyses, this fungus was shown to be a yeast (hemiascomycetes). The discovery of this species solves an important question in ascomycete classification, i.e., what is the proper classification of the genus Trichomonascus, which is morphologically intermediate between two major groups of ascomycete fungi.
Technical Abstract: Two new yeasts are described that were recognized as novel from nucleotide divergence in domains D1/D2 of 26S rDNA. The new species and their type strains are the following: Trichomonascus petasosporus NRRL YB-2092T (CBS 9602T), mating type a, NRRL YB-2093 (CBS 9603), mating type alpha, and Sympodiomyces indianaensis NRRL YB-1950T (CBS 9600T). Phylogenetic analysis placed the two new taxa, which are sister species, in the Sympodiomyces clade near Blastobotrys/Stephanoascus farinosus. Placement of Trichomonascus in the Saccharomycetales resolves the earlier uncertainties surrounding the classification of this morphologically unusual genus.