Submitted to: International Journal of Systematic and Evolutionary Microbiology
Publication Type: Peer reviewed journal
Publication Acceptance Date: 5/21/2013
Publication Date: 8/1/2013
Citation: Lachance, M.A., Kurtzman, C.P. 2013. The yeast genus Tortispora gen. nov., description of Tortispora ganteri sp. nov., Tortispora mauiana f.a., sp. nov., Tortispora agaves f.a., sp. nov., Tortispora sangerardonensis f.a., sp. nov., Tortispora cuajiniquilana f.a., sp. nov., Tortispora starmeri f.a., sp. nov., and Tortispora phaffii f.a., sp. nov., reassignment of Candida caseinolytica to Tortispora caseinolytica f.a., comb. nov., emendation of Botryozyma, and assignment of Botryozyma, Tortispora gen. nov., and Trigonopsis to the family Trigonopsidaceae fam. nov. International Journal of Systematic and Evolutionary Microbiology. 63(8):3104-3114. Interpretive Summary: The discovery of new microbial species provides an opportunity to find novel physiological and genetic properties of interest to science and technology. Since many microorganisms look much alike under the microscope, DNA sequence comparisons are needed for accurate species identification and to determine whether species are closely or distantly related to one another. In this study, DNA sequence analysis allowed detection of seven new yeast species, which form a group that is isolated from other known yeasts. Because of their genetic isolation, the species are placed in the new genus Tortispora. The species were predominately isolated from rotting cacti in the U.S.A., Mexico, Costa Rica, and Argentina. Novel physiological properties include degradation of proteins and a unique ability to grow on butanol. Consequently, this work will be of particular interest to biotechnologists, but molecular geneticists and ecologists with an interest in the speciation process will also find these new species of value.
Technical Abstract: We describe the yeast genus Tortispora gen. nov., an early diverging lineage in the Saccharomycetales that features the formation of helical ascospores. The genus is based on 16 strains resembling Candida caseinolytica that were isolated from necrotic plant tissue in warm regions of the New World. Based on sequences of the D1/D2 domains of the nuclear large subunit rRNA genes, as well as other data, the strains are assigned to eight distinct species. The species are nutritionally specialized and share the unusual ability to hydrolyze casein and to grow on 1-butanol as sole carbon source. One species of the proposed new genus produces a simple ascus with a helical ascospore, whereas other species of the clade have failed to form ascospores. However, in conformity with the International Code of Nomenclature for Algae, Fungi, and Plants (Melbourne Code), all species in the clade, including C. caseinolytica, are assigned to Tortispora gen. nov. The new binomials are Tortispora ganteri sp. nov, type species of the genus (SUB 86-469.5 T = CBS 12581T = NRRL Y-17035T), Tortispora caseinolytica f.a., comb. nov. (UCD-FST 83-438.3T = CBS 7781T = NRRL Y 17796T), Tortispora mauiana f.a., sp. nov. (UWOPS 87-2430.3T = CBS _____T = NRRL Y-48832T), Tortispora agaves f.a., sp. nov. (UWOPS 94-257.6T = CBS _____T = NRRL Y-_____T), Tortispora sangerardii f.a., sp. nov. (UWOPS 00-157.1T = CBS _____T = NRRL Y-_____T), Tortispora cuajiniquilana f.a., sp. nov. (UWOPS 99-344.4T = CBS _____T = NRRL Y-_____T), Tortispora starmeri f.a., sp. nov. (G 91-702.5T = CBS _____T = NRRL Y _____T), and Tortispora phaffii f.a., sp. nov. (UWOPS 91-445.1T = CBS _____T = NRRL Y-48833T). In addition, species formerly assigned to Ascobotryozyma are reassigned to the genus Botryozyma. The genera Trigonopsis, Botryozyma, and Tortispora are assigned to the family Trigonopsidaceae fam. nov.