Submitted to: Canadian Journal of Botany
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: March 27, 1995
Publication Date: N/A
Interpretive Summary: The filamentous yeasts include several species that are plant pathogens and others that are used worldwide for production of vitamins and organic acids such as citric acid. Current systems of classification do not allow reliable recognition of all species or permit an understanding of their genetic relationships. The 70-plus species of interest were compared from differences in the chemical sequence of the genetic material ribosomal DNA. This comparison permitted grouping of species into genetically defined genera and showed that species and genera have unique nucleotide sequences. The sequences will be used to develop "molecular probes" for rapid species identification.
Technical Abstract: Relationships among species assigned to mycelial genera of the ascomycetous yeast clade were determined from extent of divergence in a ca. 600-nucleotide region near the 5' end of the large subunit (26S) ribosomal DNA gene. Phylogenetic analyses showed that Stephanoascus is distinct from Zygoascus and that Blastobotrys and its synonyms Sympodiomyces and Arxula represent anamorphs of Stephanoascus. The analyses showed the following taxa to be congeneric: Ambrosiozyma/Hormoascus, Saccharomycopsis/Guilliermondella/Botryoascus/ Arthroascus, Dipodascus/Galactomyces and Eremothecium/Ashbya/ Nematospora/Holleya. Species assigned to Dipodascus comprise two well- separated clades. New taxonomic combinations are proposed which reflect the phylogenetic relationships determined.