Submitted to: Federation Of European Microbiological Societies Yeast Research
Publication Type: Peer reviewed journal
Publication Acceptance Date: 6/10/2008
Publication Date: 9/1/2008
Citation: Kurtzman, C.P., Robnett, C.J., Basehoar Powers, E.A. 2008. Phylogenetic Relationships Among Species of Pichia, Issatchenkia and Williopsis Determined from Multigene Sequence Analysis, and the Proposal of Barnettozyma gen. nov., Lindnera gen. nov. and Wickerhamomyces gen. nov. Federation of European Microbiological Societies Yeast Research. 8(6):939-954. Interpretive Summary: Yeasts assigned to the genus Pichia include species that spoil foods and beverages, that are used for biocontrol of fruit and grain spoilage, and that cause human infections. Because of the importance of this genus, species identification and classification must be accurate. The approximately 100 species assigned to Pichia were compared from their differences in five gene sequences, four that code for various ribosomal RNAs and another that codes for a protein. The gene sequence analysis provided an accurate method for species identification and showed that the species separate into five genetically distinct groups, the genera Pichia and Starmera and three new genera. Results from this study will be used by taxonomists, ecologists, agriculture and food scientists and clinicians, all of whom need accurate identification of species and genera.
Technical Abstract: Relationships among species characterized by the ubiquinone CoQ-7 and inability to utilize methanol, which are assigned to the yeast genera Pichia, Issatchenkia and Williopsis, were phylogenetically analyzed from nucleotide sequence divergence in the large and small subunit rRNA genes and the gene for translation elongation factor-1alpha. The species separated into five clades. Species of Issatchenkia are members of the Pichia membranifaciens clade and are proposed for transfer to Pichia. P. dryadoides and P. quercuum are basal members of the genus Starmera. Williopsis species are dispersed among hat-spored taxa in each of the remaining three clades, which are proposed as the new genera Barnettozyma, Lindnera and Wickerhamomyces. Lineages previously classified as varieties of Pichia kluyveri, ‘Issatchenkia’ scutulata, Starmera amethionina and ‘Williopsis’ saturnus are elevated to species rank based on sequence comparisons.