ABSTRACT
Based on the base composition of nuclear DNA and DNA/DNA hybridization, Pichia galeiformis IFO 10718T was reclassified as a synonym of Pichia manshurica, and Pichia scaptomyzae IFO 1073 1T was confirmed to be a synonym of Pichia membranifaciens. Comparison of 18S rRNA gene sequences indicated that IFO 10731T (P. scaptomyzae) is identical to P. membranifaciens IFO 10215T and IFO 10725, and IFO 10718T (P. galeiformis) is identical to P. manshurica IFO 10726T. These data were consistent with the view that P scaptomyzae and P membranifaciens should be conspecific, as should P. galeiformis and P manshurica. Variation among 26S rRNA gene domain D1/D2 sequences from three P membranifaciens strains indicated that this species encompasses a genetically heterogeneous population.
Subject(s)
Pichia/classification , Pichia/genetics , Base Composition , DNA, Fungal/analysis , DNA, Fungal/chemistry , DNA, Fungal/genetics , DNA, Ribosomal/analysis , DNA, Ribosomal/chemistry , DNA, Ribosomal/genetics , Molecular Sequence Data , Mycological Typing Techniques , Nucleic Acid Hybridization , RNA, Ribosomal/genetics , RNA, Ribosomal, 18SABSTRACT
Three new yeast species were isolated from soil and partially decayed leaves in Yaku Island and Iriomote Island in the Nansei Islands of Japan. Based on DNA hybridization and physiological characters, these represent novel taxa. These are designated Saccharomyces naganishii sp. nov. (type strain IFO 10181T = CBS 8797T), Saccharomyces humaticus sp. nov. (type strain IFO 10673T = CBS 8893T) and Saccharomyces yakushimaensis sp. nov. (type strain IFO 1889T = CBS 8894T). The phylogenetic relationships of the three new species with members of other ascomycetous genera (e.g. Kluyveromyces, Saccharomyces, Torulaspora and Zygosaccharomyces) were estimated by 18S rDNA gene sequence analysis.
Subject(s)
Plant Leaves/microbiology , Saccharomyces/classification , Saccharomyces/genetics , Soil Microbiology , Base Composition , Electrophoresis, Gel, Pulsed-Field , Japan , Karyotyping , Molecular Sequence Data , Nucleic Acid Hybridization , Phylogeny , RNA, Ribosomal/genetics , RNA, Ribosomal, 18S/genetics , Saccharomyces/chemistry , Saccharomyces/physiology , Sequence Analysis, DNA , Ubiquinone/analysisABSTRACT
Forty strains which were stocked as Pichia membranifaciens sensu Kurtzman and 9 strains stocked as Candida valida, anamorphs of P. membranifaciens, in the Institute for Fermentation, Osaka (IFO) were reclassified based on the data of base composition of nuclear DNA, DNA/DNA hybridization, coenzyme Q system, electrophoretic karyotype, and base sequence of 18S rDNA. P. membranifaciens complex was assigned into 3 groups: (I) P. membranifaciens group, including 25 strains with high DNA homologies to the type strain of P. membranifaciens (72-98%); (II) P. manshurica group, including 18 strains with high DNA homology of 79-95% to the type strain of P. manshurica; and a group including the remaining 6 strains, which had low DNA homology to the above two species. GC content was 42.9-45.3 mol% for the P. membranifaciens group, 40.0-42.0 mol% for the P. manshurica group, and 27.2-44.7 mol% for the remaining group. All three groups had ubiquinone Co Q-7. Of the 6 anomalous strains, IFO 0162 was identified as Pichia deserticola, and IFO 0839 and IFO 0840 were identified as Issatchenkia occidentalis; but IFO 0842, IFO 0843, and IFO 1788 were thought to be unknown strains.
Subject(s)
Pichia/classification , Base Composition , DNA, Fungal/analysis , DNA, Ribosomal/analysis , Electrophoresis, Gel, Pulsed-Field , Karyotyping , Nucleic Acid Hybridization , Phylogeny , Pichia/isolation & purification , RNA, Ribosomal, 18S/analysis , Sequence Analysis, DNA , Ubiquinone/analysisABSTRACT
Seven strains of three new yeast species were isolated from soil, flowers and leaves in the Nansei Islands, Japan. These isolates most closely resembled Kluyveromyces phaffii in physiological characteristics and nuclear DNA base composition (30-32 mol% G + C), but on the basis of DNA-DNA hybridization and electrophoretic karyotyping they were categorized into three new species different from K. phaffii. Phylogenetic analysis using 18S rRNA gene sequences showed that the three new species and K. phaffii were highly related to one another and phylogenetically separate from the members of other species. On the basis of phylogeny and physiological characters, it is proposed that the three new species represent novel taxa and should be designated Tetrapisispora iriomotensis gen. nov., sp. nov. (type strain IFO 10929T), Tetrapisispora nanseiensis gen. nov., sp. nov. (type strain IFO 10899T) and Tetrapisispora arboricola gen. nov., sp. nov. (type strain IFO 10925T), while Kluyveromyces phaffii becomes Tetrapisispora phaffii comb. nov.
