Three ascomycetous yeast strains, H-6T, ZX-15 and ZX-20, isolated from the bark of two tree species of the family Fagaceae collected from different regions of China, formed unconjugated and persistent asci containing two to four globose ascospores. 26S rDNA D1/D2 domain and internal transcribed spacer (ITS) region (including 5.8S rDNA) sequence analysis showed that they were closely related to the currently accepted Saccharomyces species with strong support. Comparisons of the rDNA sequences, electrophoretic karyotypes and physiological characters indicated that the three strains represent a novel species in the genus Saccharomyces. The name Saccharomyces arboricolus sp. nov. was proposed for the novel species, with H-6T (=AS 2.3317T=CBS 10644T) isolated from the bark of Quercus fabri as the type strain.
Two yeast strains (TM2-16 and PT1-17T) were isolated by membrane filtration from samples of estuarine water collected from two mangrove forests, in Khao Lumpee-Haad Thaimueang National Park and Mu Ko Ra-Ko Prathong National Park, Phang-Nga Province, Thailand. Analysis of the D1/D2 domain of the large-subunit rDNA sequences revealed that the sequences of the two strains were identical. The closest species in terms of pairwise sequence similarity was Candida galli, but the level of nucleotide substitutions (13.2 %) was sufficient to justify the description of a separate species. Phylogenetic analysis demonstrated that the two strains occupy a basal position with respect to Yarrowia lipolytica and C. galli of the Yarrowia clade, supported by a high bootstrap value. The two strains showed identical phenotypic characteristics, including proliferation by multilateral budding, absence of ascospores and ballistoconidia and negative Diazonium blue B and urease reactions. The major ubiquinone was Q-9. On the basis of the above findings, these two strains were assigned to a single novel species of the genus Candida, for which the name Candida phangngensis sp. nov. is proposed. The type strain is PT1-17T (=BCC 21231T =NBRC 101967T =CBS 10407T).
The teleomorph of Candida cleridarum was discovered through the detection of conjugation between isolates of a large collection from the nitidulid beetles of the genus Carpophilus found in the flowers of various cacti in Arizona, USA. The previous oversight of the sexual cycle of this yeast is attributed to the inequality (ca. 5 : 1) of the two mating types. Extensive conjugation between compatible mating types is observed after overnight incubation on 5 % malt agar, followed after 3–5 days by the formation of mature asci. The hat-shaped ascospores are reminiscent of those seen in Kodamaea species, which are members of the same guild. However, published analyses of D1/D2 large subunit rDNA sequences indicate an affinity with the genus Debaryomyces. As the latter is polyphyletic and morphologically heterogeneous, and in view of the distinct life cycle of the new teleomorph, the new genus Kurtzmaniella is described with a novel species, Kurtzmaniella cleridarum sp. nov. Given the close relatedness of Kurtzmaniella cleridarum sp. nov. to Candida quercitrusa, Candida oleophila and Candida railenensis, for which several natural isolates were available, strains of these species were mixed in pairs under the conditions found favourable for the former. Conjugation was not detected in those species. The type strain of Kurtzmaniella cleridarum sp. nov. is UWOPS 99-101.1T (=CBS 8793T=NRRL Y-48386T, h+ ), type of Candida cleridarum. The allotype is UWOPS 07-123.1 (=CBS 10688=NRRL Y-48387, h− ).