Motofumi Suzuki

Fungus Symbionts Colonizing the Galleries of the Ambrosia Beetle Platypus quercivorus

Isolations were made to determine the fungal symbionts colonizing Platypus quercivorus beetle galleries of dead or dying Quercus laurifolia, Castanopsis cuspidata, Quercus serrata, Quercus crispula, and Quercus robur. For these studies, logs from oak wilt-killed trees were collected from Kyoto Prefecture, Japan. Fungi were isolated from the: (1) entrances of beetle galleries, (2) vertical galleries, (3) lateral galleries, and (4) the larval cradle of P. quercivorus in each host tree. Among the fungus colonies which appeared on YM agar plates, 1,219 were isolated as the representative isolates for fungus species inhabiting in the galleries based on their cultural characteristics. The validity of the visual classification of the fungus colonies was checked and if necessary properly corrected using microsatellite-primed PCR fingerprints. The nucleotide sequence of the D1/D2 region of the large subunit nuclear rRNA gene detected 38 fungus species (104 strains) of which three species, i.e., Candida sp. 3, Candida kashinagacola (both yeasts), and the filamentous fungus Raffaelea quercivora were isolated from all the tree species. The two yeasts were most prevalent in the interior of galleries, regardless of host tree species, suggesting their close association with the beetle. A culture-independent method, terminal restriction fragment length polymorphism (T-RFLP) analysis was also used to characterize the fungus flora of beetle galleries. T-RFLP patterns showed that yeast species belonging to the genus Ambrosiozyma frequently occurred on the gallery walls along with the two Candida species. Ours is the first report showing the specific fungi inhabiting the galleries of a platypodid ambrosia beetle.

A novel ascosporogenous yeast species, Zygosaccharomyces siamensis, and the sugar tolerant yeasts associated with raw honey collected in Thailand

Diversity of yeasts in association with bees and their food sources has been explored during the last decade. In Thailand, there has been no study of yeast identification in honey and bees. Hence, a total of 186 yeast strains were isolated from 37 honey samples of 12 different bee species. On the basis of morphological and physiological characteristics, 55 representative strains were chosen and identified by sequence analysis of the 26S rDNA D1/D2 domain and the ITS region. The data were compared with the published sequences and the results showed the occurrence of 19 ascomycetous and 1 basidiomycetous yeast species. Six strains of the new species were isolated. Phylogenetic analysis of the 26S rDNA D1/D2 sequence revealed that they were conspecific and most closely related to Zygosaccharomyces mellis. Based on the ITS sequence, the new species was clustered with the type β and clearly distinguished from the type α. Sequence analysis of combined ITS-26S rDNA D1/D2 showed similar results. The occurrence of these two types, with a divergence of more than 1% in their sequences, and low DNA relatedness among them suggested that members of the type β can be regarded as separate species. An analysis of the morphological and physiological characteristics was performed. Ascospore formation was observed on acetate agar and Gorodkowa agar. The new Zygosaccharomyces species differed physiologically from Z. mellis in 4 assimilation tests. This data supports the hypothesis that the new species, Zygosaccharomyces siamensis, is a novel ascosporogenous yeast. The type strain is JCM 16825T (=CBS 12273T) and a description is given here.

Candida kashinagacola sp. nov., C. pseudovanderkliftii sp. nov. and C. vanderkliftii sp. nov., three new yeasts from ambrosia beetle-associated sources

Three new yeast species, Candida kashinagacola (JCM 15019Txa0=xa0CBS 10903T), C. pseudovanderkliftii (JCM 15025Txa0=xa0CBS 10904T), and C. vanderkliftii (JCM 15029Txa0=xa0CBS 10905T) are described on the basis of comparison of nucleotide sequences of large subunit ribosomal DNA D1/D2 region (LSU rDNA D1/D2). The nearest assigned species of the three new species was Candidallanquihuensis. Candida kashinagacola and C. pseudovanderkliftii differed from C. llanquihuensis by 3.8% nucleotide substitution of the region, while C. vanderkliftii did by 4.4%. Three new species differed in a number of physiological and growth characteristics from any previously assigned species and from one another. A phylogenetic tree based on the sequences of LSU rDNA D1/D2 showed that these new species together with Candida sp. ST-246, Candida sp. JW01-7-11-1-4-y2, Candida sp. BG02-7-20-001A-2-1 and C. llanquihuensis form a clade near Ambrosiozyma species. The new species did not assimilate methanol as a sole source of carbon, which supported the monophyly of these non methanol-assimilating species which are closely related to the methylotrophic yeasts. Candida kashinagacola was frequently isolated from the beetle galleries of Platypus quercivorus in three different host trees (Quercus serrata, Q. laurifolia and Castanopsis cuspidata) located in the sourthern part of Kyoto, Japan, thus indicating that this species may be a primary ambrosia fungus of P. quercivorus. On the other hand, C. pseudovanderkliftii and C. vanderkliftii were isolated only from beetle galleries in Q. laurifolia. Candida vanderkliftii was isolated from beetle gallery of Platypus lewisi as well as those of P. quercivorus. Candida pseudovanderkliftii and C. vanderkliftii are assumed to be auxiliary ambrosia fungi of P. quercivorus.

Metschnikowia viticola sp. nov., a new yeast species from grape

Two yeast strains, producing needle-shaped ascospores under suitable conditions, were isolated from grapes grown in Hungary. Based on these two strains, Metschnikowia viticola (type strain NCAIM Y.01705, CBS 9950, JCM 12561) is proposed as a new yeast species. Considering its phenotypic features, the restriction fragment patterns of 18S rDNA and the sequence of the D1/D2 domain of 26S rDNA, the proposed new species is closely related to Candida kofuensis.

Spencermartinsiella europaea gen. nov., sp. nov., a new member of the 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-α, 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) (u200a=u200aNRRL Y-48265(T)u200a=u200a CBS 11730(T)) and NCAIM Y.01819(I) (u200a=u200aNRRL Y-48266(I)u200a=u200aCBS 11731(I)), respectively.

Ambrosiozyma kamigamensis sp. nov. and A. neoplatypodis sp. nov., two new ascomycetous yeasts from ambrosia beetle galleries

Two new yeast species of the genus Ambrosiozyma are described on the basis of comparison of nucleotide sequences of large subunit of ribosomal DNA D1/D2 region. Ambrosiozymaxa0kamigamensis and Ambrosiozymaxa0neoplatypodis differ from Ambrosiozymaxa0ambrosiae by 17 nucleotides (3.0%) and 16 nucleotides (2.8%), respectively, out of 565. The two species differ from each other by 13 nucleotides. Ambrosiozymaxa0kamigamensis was isolated from galleries of the ambrosia beetle, Platypusxa0quercivorus, in specimens of Quercusxa0laurifolia and Castanopsisxa0cuspidata located in the southern part of Kyoto, Japan. Ambrosiozymaxa0neoplatypodis was isolated from similar material, but only in Q.xa0laurifolia. Ambrosiozymaxa0kamigamensis can be distinguished from the other Ambrosiozyma species by the inability to assimilate erythritol, whereas A.xa0neoplatypodis can be distinguished by the ability to assimilate both l-arabinose and nitrate. The type strains of A.xa0kamigamensis and A.xa0neoplatypodis are JCM 14990T (=CBS 10899T) and JCM 14992T (=CBS 10900T), respectively. This is the first report of new Ambrosiozyma species since the genus was proposed.

Diversity and Fermentation Products of Xylose-Utilizing Yeasts Isolated from Buffalo Feces in Thailand

Twenty-eight xylose-utilizing yeast strains were isolated by enrichment culture from 11 samples of feces from the rectum of Murrah buffalo and Swamp buffalo in Thailand. On the basis of their morphological and biochemical characteristics, including sequence analysis of the D1/D2 region of the large-subunit ribosomal RNA gene (LSU rDNA), they were identified as Candida tropicalis (designated as Group I, 11 isolates), Candida parasilosis (Group II, 2 isolates), Candida mengyuniae (Group III, 2 isolates), Sporopachydermia lactativora (Group IV, 2 isolates), Geotrichum sp. (Group V, 5 isolates) and Trichosporon asahii (Group VI, 6 isolates). All isolates utilized xylose as the sole carbon source but 27 isolates could ferment xylose to ethanol (0.006–0.602 g L−1) and 21 isolates could ferment xylose to xylitol (0.19–22.84 g L−1). Candida tropicalis isolates produced the highest yield of xylitol (74.80%). Their ability to convert xylose to xylitol and ethanol ranged from 15.06 g L−1 to 22.84 g L−1 xylitol and 0.110 g L−1 to 0.602 g L−1 ethanol, respectively.

Debaryomyces Lodder & Kreger-van Rij (1952)

Publisher Summary This chapter studies the genus Debaryomyces. In the determination of asexual reproduction, cell division is by multilateral budding. Pseudohyphae may be absent or poorly developed. In sexual reproduction it is seen that asci show conjugation between a cell and its bud, or between independent cells. Ascospores are globose, ovoid, or lenticular and have smooth or warty walls that may also have spiral ridges. Ascospores are not liberated from the ascus except in one species. In physiology and biochemistry it is seen that fermentation is positive, weak, or absent. Nitrate is not assimilated. The major ubiquinone is CoQ-9. The diazonium blue B reaction is negative. This study further examines the phylogenetic placement where Debaryomyces and Schwanniomyces are sister genera. The type of species mentioned is Debaryomyces hansenii. The species accepted are Debaryomyces coudertii, Debaryomyces fabryi, Debaryomyces hansenii, Debaryomyces maramus, Debaryomyces mycophilus, Debaryomyces nepalensis, Debaryomyces prosopidis, Debaryomyces robertsiae, Debaryomyces singareniensis, Debaryomyces subglobosus, and Debaryomyces udenii. The systematic discussion of the species includes synonyms, growth in YM broth, growth on YM agar, growth on the surface of YM broth, Dalmau plate culture on corn meal agar, formation of ascospores, CoQ, Mol% G1C, gene sequence accession numbers, type strain, cell carbohydrates, origin of the strain studied, systematics, ecology, biotechnology, agriculture and food, and clinical importance.

Schwanniomyces Klöcker emend. M. Suzuki & Kurtzman (2010)

Publisher Summary This chapter studies the genus Schwanniomyces. In the determination of the asexual reproduction it is seen that cells divide by multilateral budding and are spherical to elongate. Pseudohyphae may form, but septate hyphae are absent. In sexual reproduction it is found that the asci may be unconjugated or show conjugation between a cell and its bud or between independent cells. Species form one to four globose ascospores that may be glabrous, roughened, or roughened and with an equatorial ledge. The chapter also discusses physiology/biochemistry and phylogenetic placement of the genus in which sugars may be fermented and various sugars, polyols, and organic acids are assimilated but nitrate is not utilized. The major ubiquinone is CoQ-9 and the diazonium blue B reaction is negative. The type species taken is Schwanniomyces occidentalis. This study examines Debaryomyces and Schwanniomyces species and notes the species of Schwanniomyces clustered with certain Debaryomyces species, such as D. polymorphus.

Two new species of the genus Candida in the Zygoascus clade, Candida lundiana sp. nov. and Candida suthepensis sp. nov., isolated from raw honey in Thailand

During a survey of yeasts associated with raw honey collected in Thailand, two strains of the Zygoascus clade were isolated from the Asian cavity-nesting honeybee Apis cerana and the stingless bee Homotrigona fimbriata. Phylogeny based on 26S rDNA D1/D2 sequences placed these yeasts as members of a clade including Candida bituminiphila, Candida patagonica and Candida polysorbophila. The strains of the two novel species, CBS 12271T and CBS 12270T, respectively, could be unquestionably distinguished from their relatives by rDNA sequences and other taxonomic characteristics. Therefore, the novel anamorphic species, Candida lundiana sp. nov. (type strain CBS 12271Txa0=xa0JCM 16823T) and Candida suthepensis sp. nov. (type strain CBS 12270Txa0=xa0JCM 16822T) are described.