Relationships among species assigned to the ascosporic yeast genera Sporopachydermia, Stephanoascus, Trichomonascus, Wickerhamiella and Zygoascus, and to the associated anamorphic genera Arxula, Blastobotrys, Sympodiomyces and Trigonopsis, were determined from phylogenetic analyses of gene sequences from the nearly complete large-subunit rRNA gene, the mitochondrial small-subunit rRNA gene, and cytochrome oxidase II. The genus Stephanoascus is polyphyletic, resulting in reassignment of two species to the older genus Trichomonascus and the third to Sugiyamaella gen. nov. (type species Sugiyamaella smithiae). The genera Sporopachydermia, Wickerhamiella and Zygoascus appear to be monophyletic. The species Pichia ofunaensis and P. tannicola are proposed for transfer to Zygoascus. Arxula, Blastobotrys and Sympodiomyces are members of the Trichomonascus clade, with the genus Blastobotrys having taxonomic priority for anamorphic states. Trigonopsis variabilis and three species of Candida represent a distinct clade. From the foregoing gene sequence analyses, the new ascosporic genus Sugiyamaella is proposed, as are 14 new species combinations and the new family Trichomonascaceae.

Ten strains of a novel heterothallic yeast species were isolated from rotten wood collected at different locations in Hungary. Analysis of gene sequences for the D1/D2 domain of the large subunit rRNA, as well as analysis of concatenated gene sequences for the nearly complete nuclear large subunit rRNA, nuclear small subunit rRNA and translation elongation factor 1-�\, placed the novel species in the family Trichomonascaceae, but showed that it was distinct from all currently recognized genera. The name Spencermartinsiella europaea gen. nov., sp. nov. is proposed to accommodate the new genus and novel species. The novel species could be distinguished from recognized species of neighbouring genera on the basis of standard phenotypic characteristics. The type and isotype strains of Spencermartinsiella europaea are NCAIM Y.01817(T) (= NRRL Y-48265(T) = CBS 11730(T)) and NCAIM Y.01819(I) (= NRRL Y-48266(I) = CBS 11731(I)), respectively.

Yeasts of the artificial genus Candida include plant endophytes, insect symbionts, and opportunistic human pathogens. Phylogenies based on rRNA gene and actin sequences confirmed that the genus is not monophyletic, and the relationships among Candida species and allied teleomorph genera are not clearly resolved. Protein-coding genes have been useful to resolve taxonomic positions among a broad range of fungi. Over 70 taxa of the genus Candida and its allied sexually reproducing genera were therefore selected, and their phylogenetic relationships were investigated using nuclear sequences of the largest subunit and second largest subunit of RNA polymerase II gene, actin, the second subunit of the mitochondrial cytochrome oxidase gene, and D1/D2 LSU rRNA gene. The DNA sequences were analysed by maximum parsimony and Bayesian inference, resulting in the recognition of six major phylogenetic groups (A-F). Group A contains six facultative pathogenic Candida species, which seem to have derived from nonpathogenic species, while Group B contains species of Clavispora, Metschnikowia, and Pichia guilliermondii. Species of Debaryomyces form an independent group C that is related to groups A and B. Pichia fermentans and other environmental species are concentrated in Group D. Group E, containing Pichia anomala, may be a sibling to group F, which is represented by the Saccharomyces species complex.

Relationships among ascomycetous yeast genera (subphylum Saccharomycotina, phylum Ascomycota) have been uncertain. In the present study, type species of 70 currently recognized genera are compared from divergence in the nearly entire nuclear gene sequences for large subunit rRNA, small subunit (SSU) rRNA, translation elongation factor-1�\, and RNA polymerase II, subunits 1 (RPB1) and 2 (RPB2). The analysis substantiates earlier proposals that all known ascomycetous yeast genera now assigned to the Saccharomycotina represent a single clade. Maximum likelihood analysis resolved the taxa into eight large multigenus clades and four-one- and two-genus clades. Maximum parsimony and neighbor-joining analyses gave similar results. Genera of the family Saccharomycetaceae remain as one large clade as previously demonstrated, to which the genus Cyniclomyces is now assigned. Pichia, Saturnispora, Kregervanrija, Dekkera, Ogataea and Ambrosiozyma are members of a single large clade, which is separate from the clade that includes Barnettozyma, Cyberlindnera, Phaffomyces, Starmera and Wickerhamomyces. Other clades include Kodamaea, Metschnikowia, Debaryomyces, Cephaloascus and related genera, which are separate from the clade that includes Zygoascus, Trichomonascus, Yarrowia and others. This study once again demonstrates that there is limited congruence between a system of classification based on phenotype and a system determined from DNA sequences.