Three new ascomycetous yeasts from insect-associated arboreal habitats

A new species of Pichia and two new species of Candida are described and were determined to be genetically isolated from all other currently recognized ascomycetous yeasts from their sequence divergence in the species-variable D1/D2 domain of large subunit (26S) ribosomal DNA. The three species were primarily isolated from the frass of wood-boring insects living in pine and spruce trees. The new species and their type strains are the following: Pichia ramenticola NRRL YB-1985 (CBS 8699), mating type alpha (NRRL YB-3835, CBS 8700, mating type a), Candida piceae NRRL YB-2107 (CBS 8701), and Candida wyomingensis NRRL YB-2152 (CBS 8703). Pichia ramenticola and C. piceae assimilate methanol as a carbon source; P. ramenticola is the first known heterothallic ascomycetous yeast to utilize this compound.     

Polyphasic identification of yeasts isolated from bark of cork oak during the manufacturing process of cork stoppers

A two-step protocol was used for the identification of 52 yeasts isolated from bark of cork oak at initial stages of the manufacturing process of cork stoppers. The first step in the identification was the separation of the isolates into groups by their physiological properties and RFLPs of the ITS-5.8S rRNA gene. The second step was the sequencing of the D1/D2 domains of the 26S rRNA gene of selected isolates representing the different groups. The results revealed a predominance of basidiomycetous yeasts (11 species), while only two species represented the ascomycetous yeasts. Among the basidiomycetous yeasts, members representing the species Rhodosporidium kratochvilovae and Rhodotorula nothofagi, that have been previously isolated from plant material, were the most abundant. Yeasts pertaining to the species Debaryomyces hansenii var. fabryii, Rhodotorula mucilaginosa and Trichosporon mucoides were isolated in small numbers.     

Yeasts and Yeast-Like Fungi Associated with Tree Bark: Diversity and Identification of Yeasts Producing Extracellular Endoxylanases

A total of 239 yeast strains was isolated from 52 tree bark samples of the Medaram and Srisailam forest areas of Andhra Pradesh, India. Based on analysis of D1/D2 domain sequence of 26S rRNA gene, 114 strains were identified as ascomycetous; 107 strains were identified as basidiomycetous yeasts; and 18 strains were identified as yeast-like fungi. Among the ascomycetous yeasts, 51% were identified as members of the genus Pichia, and the remaining 49% included species belonging to the genera Clavispora, Debaryomyces, Kluyveromyces, Hanseniaspora, Issatchenkia, Lodderomyces, Kodamaea, Metschnikowia, and Torulaspora. The predominant genera in the basidiomycetous yeasts were Cryptococcus (48.6%), Rhodotorula (29%), and Rhodosporidium (12.1%). The yeast-like fungi were represented by Aureobasidium pullulans (6.7%) and Lecythophora hoffmanii (0.8%). Of the 239 yeast strains tested for Xylanase, only five strains of Aureobasidium sp. produced xylanase on xylan-agar medium. Matrix-assisted laser desorption ionization-time of flight analysis and N-terminal amino-acid sequence of the xylanase of isolate YS67 showed high similarity with endo-1-4-β-xylanase (EC 3.2.1.8) of Aureobasidium pullulans var. melanigenum. Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

Two new ballistoconidium-forming yeast species, Bullera melastomae and Bullera formosana, found in Taiwan

Two yeast strains, the cells of which contained xylose and Q-10 as the major ubiquinone, were isolated from a plant leaf collected in Taiwan. These yeasts were found to represent two new species of the genus Bullera in the Hymenomycetes. Identification was based on the sequence analysis of the 18S rDNA, the internal transcribed spacer (ITS) regions and the D1/D2 domain of 26S rDNA. The yeasts are named Bullera melastomae sp. nov. and Bullera formosana sp. nov. In the phylogenetic trees based on 18S rDNA and D1/D2 domain of 26S rDNA sequences, these two species constitute a cluster connected with Dioszegia cluster in the Cryptococcus luteolus lineage.     

假丝酵母属疑难菌株大亚基rDNA D1/D2区域序列分析及其分类学意义

对根据常规形态和生理生化性状难以确定分类学地位的8株假丝酵母菌,进行了以大亚基(26S) rDNA中D1/D2区域(约500～600 bp)的碱基序列分析为依据的分子分类学研究.根据系统树上所显示的供试菌株与假丝酵母属及相关子囊菌酵母已知种的亲缘关系,以及与最近缘种模式菌株D1/D2区域序列的相似性比较,确定了各个菌株的归属.本研究也显示了DNA序列分析在假丝酵母菌快速鉴定中的优越性.     

Three new species of Candida from apple cider: C. anglica, C. cidri and C. pomicola

Three new anamorphic ascomycetous yeasts are described: Candida anglica (type strain NRRL Y-27079, CBS 4262), Candida cidri (type strain NRRL Y-27078, CBS 4241), and Candida pomicola (type strain NRRL Y-27083, CBS 4242). These three species were isolated from cider produced in the United Kingdom, and their identification was determined from unique nucleotide sequences in the species-specific D1/D2 domain of large subunit (26S) ribosomal DNA. Phylogenetic analysis of D1/D2 sequences placed C. anglica near Candida fragi, C. cidri near Pichia capsulata, and C. pomicola in the Pichia holstii clade.     

Relation between phylogeny and physiology in some ascomycetous yeasts

The question of whether yeasts with similar physiological properties are closely related has been examined using recently published phylogenetic analyses of 26S domain D1/D2 rDNA nucleotide sequences from all currently recognized ascomycetous yeasts. When apparently unique metabolic pathways are examined, some relationships between physiology and rDNA phylogeny are evident. Most Candida and Pichia species that are able to assimilate methanol as the sole carbon source are in a clade delimited by C. nanospora and C. boidinii. Exceptions are P. capsulata and P. pastoris which are phylogenetically separated from the other methanol-assimilating yeasts. Yeasts subject to the petite mutation, resulting in respiratory deficiency, belong to three different clades, viz. a Saccharomyces clade delimited by S. cerevisiae and S. rosinii,the Dekkera/Brettanomyces clade, and some Schizosaccharomyces species (‘Archiascomycete’ clade). However, petite mutants were also found in Zygosaccharomyces fermentati and some other more distantly related species. Yeasts able to assimilate n-hexadecane, uric acid or amines as sole carbon source are broadly distributed over the ascomycetous phylogenetic tree. However, species that assimilate adenine as sole carbon source are closely related. Most of these species also assimilated glycine, uric acid, n-hexadecane, putrescine and branched-chain aliphatic compounds such as isobutanol, leucine and isoleucine. Among the Saccharomycetales, species utilizing all or the great majority of these eight compounds are in the Stephanoascus/Arxula/Blastobotrys clade. Candida blankii, which is distantly related to this clade, proved to be an exception and assimilated six of eight of these compounds. This revised version was published online in June 2006 with corrections to the Cover Date.     

Yeasts in an industrial malting ecosystem

The malting ecosystem consists of two components: the germinating cereal grains and the complex microbial community. Yeasts and yeast-like fungi are an important part of this ecosystem, but the composition and the effects of this microbial group have been largely unknown. In this study we surveyed the development of yeasts and yeast-like fungi in four industrial scale malting processes. A total of 136 malting process samples were collected and examined for the presence of yeasts growing at 15, 25 and 37°C. More than 700 colonies were isolated and characterized. The isolates were discriminated by PCR-fingerprinting with microsatellite primer (M13). Yeasts representing different fingerprint types were identified by sequence analysis of the D1/D2 domain of the 26S rRNA gene. Furthermore, identified yeasts were screened for the production of α-amylase, β-glucanase, cellulase and xylanase. A numerous and diverse yeast community consisting of both ascomycetous (25) and basidiomycetous (18) species was detected in the various stages of the malting process. The most frequently isolated ascomycetous yeasts belonged to the genera Candida, Clavispora, Galactomyces, Hanseniaspora, Issatchenkia, Pichia, Saccharomyces and Williopsis and the basidiomycetous yeasts to Bulleromyces, Filobasidium, Cryptococcus, Rhodotorula, Sporobolomyces and Trichosporon. In addition, two ascomycetous yeast-like fungi (black yeasts) belonging to the genera Aureobasidium and Exophiala were commonly detected. Yeasts and yeast-like fungi produced extracellular hydrolytic enzymes with a potentially positive contribution to the malt enzyme spectrum. Knowledge of the microbial diversity provides a basis for microflora management and understanding of the role of microbes in the cereal germination process.     

秦岭地区子囊菌酵母物种多样性研究

从陕西秦岭地区的果实和叶等不同基物上分离得到子囊菌酵母262株,利用26SrDNA的D1/D2区域序列分析并结合形态学特征对这些菌株进行了分类学研究,探讨了该地区子囊菌酵母的物种多样性及其分布。共鉴定出10属31种,其中优势属为假丝酵母属Candida,12种,(其中新种2个,另文发表)、酿酒酵母属Saccharomyces,5种、毕赤酵母属Pichia,5种和有孢汉逊酵母属Hanseniaspora,3种。对分离自陕西秦岭不同地区与海拔的同一个种的不同菌株进行了D1/D2序列分析比较,以探讨子囊菌酵母种内序列稳定性和变异幅度。     

Sporobolomyces magnisporus sp. nov., a new yeast species in the Erythrobasidium cluster isolated from plants in Taiwan

Two strains of yeasts that contain Q-10 as the major ubiquinone, lack cellular xylose and produce large bilaterally symmetrical ballistoconidia were isolated from plants collected in a protected subtropical rain forest in Taiwan and were found to represent a new species. The taxonomic properties of this species coincide with the genus Sporobolomyces, so it is described as Sporobolomyces magnisporus sp. nov. In phylogenetic trees based on the nucleotide sequences of 18S ribosomal DNA and D1/D2 domain of 26S ribosomal DNA, this species is located in the Erythrobasidium cluster.     

Sporobolomyces diospyroris sp. nov., Sporobolomyces lophatheri sp. nov. and Sporobolomyces pyrrosiae sp. nov., three new species of ballistoconidium-forming yeasts in the Agaricostilbum lineage isolated from plants in Taiwan

Three strains of xylose-lacking and ubiquinone-10-having ballistoconidium-forming yeasts isolated from plant leaves collected in Taiwan were found to represent respective new species. In phylogenetic trees constructed based on the nucleotide sequences of 18S rDNA and D1/D2 domain of 26S rDNA, they were located in the Agaricostilbum lineage (Agaricostilbum/Bensingtonia cluster). Since the taxonomic properties of these species coincide with those of the genus Sporobolomyces, they are described as Sporobolomyces diospyroris sp. nov., Sporobolomyces lophatheri sp. nov. and Sporobolomyces pyrrosiae sp. nov., respectively.     

Bullera koratensis sp. nov. and Bullera lagerstroemiae sp. nov., two new ballistoconidium-forming yeast species in the Trichosporonales clade isolated from plant leaves in Thailand

Seven strains of ballistoconidiogenous yeasts that contain xylose, form Q-10 ubiquinone, propagate by budding and don't produce stalk conidia were isolated from plant leaves collected in Thailand and were found to represent two new species. The taxonomic properties of the two species coincided with the genus Bullera so they are described as Bullera koratensis sp. nov. and Bullera lagerstroemiae sp. nov. In phylogenetic trees based on the nucleotide sequences of 18S ribosomal DNA and the D1/D2 domain of 26S rDNA, these two species are located in the Trichosporonales clade (Cryptococcus humicola-Trichosporon lineage).     

A phylogenetic study of ubiquinone Q-8 species of the genera Candida,Pichia, and Citeromyces based on 18S ribosomal DNA sequence divergence

To clarify phylogenetic relationships among species of the anamorphic ascomycetous genus Candida with ubiquinone Q-8, we determined complete sequences of 18S ribosomal RNA genes (18S rDNAs) from the type strains of 20 species of the genus Candida and 7 of the teleomorphic ascomycetous genera Pichia and Citeromyces, which have Q-8 as the major ubiquinone. Q-8-forming Candida species were divided into six clusters and were phylogenetically distant from a group of Candida species that included the type species of the genus. One Q-8-forming species from each of the genera Pichia, Citeromyces, or Clavispora was included in five of six clusters. Cluster 1 comprised C. ishiwadae, C. ernobii, C. karawaiewii, C. anatomiae, C. populi, and Pichia holstii. Cluster 2 comprised C. globosa and its teleomorph, Citeromyces matritensis. Cluster 3 comprised C. molischiana and Pichia capsulata. Cluster 4 comprised C. silvanorum, C. sequanensis, C. fennica, C. entomophila, C. homilentoma, C. rhagii, C. gotoi, and Pichia burtonii. Cluster 5 comprised C. fructus, C. musae, and C. lusitaniae (anamorph of Clavispora lusitaniae). Cluster 6 comprised C. stellata, C. lactiscondensi, C. galacta, and C. incommunis and was a heterogeneous group with large interspecific divergence. Pichia pastoris was quite divergent and phylogenetically distant from other Pichia species examined. Pichia methanolica and its synonym, P. cellobiosa, which have both Q-7 and Q-8 as major ubiquinones, were closely associated with Q-7-forming Williopsis salicorniae. Based on this comparative analysis of 18S rDNA sequences, it is evident that Q-8 Candida species and Q-8 Pichia species are polyphyletic.     

Four novel species of the anamorphic yeast genus Candida found in Thailand and Taiwan

Four strains of yeasts isolated in Thailand and Taiwan were found to represent four distinct novel species of the ascomycetous anamorphic yeast genus Candida. These strains are located in the Clavispora-Metschnikowia clade in a phylogenetic tree based on the D1/D2 domain sequences of the large subunit rRNA genes. Together with Candida picinguabensis and Candida saopaulonensis, the four novel species constitute a well-separated subclade from other species of the Clavispora-Metschnikowia clade. Three species from Thailand are described as Candida bambusicola sp. nov. (type strain, ST-50(T) = BCC 7750(T) = NBRC 106734(T) = CBS 11723(T)), Candida nongkhaiensis sp. nov. (type strain, ST-95(T) = BCC 8331(T) = NBRC 105874(T) =CBS 11724(T)) and Candida succicola sp. nov. (type strain, ST-631(T) = BCC 15314(T) = NBRC 106736(T) = CBS 11726(T)), respectively, and the species from Taiwan is described as Candida touchengensis sp. nov. (type strain, SY4S03(T) = NBRC 102647(T) = BCRC 23097(T) = CBS 10585(T)).     

Bullera begoniae sp. nov. and Bullera setariae sp. nov., two new species of ballistoconidium-forming yeasts in the Bullera variabilis (Bulleribasidium) cluster isolated from plants in Taiwan

Two strains of xylose-containing and Q-10-having ballistoconidiogenous yeasts isolated from plant leaves collected in Taiwan were found to represent two new species of the genus Bullera. In the phylogenetic trees based on the sequence analysis of 18S rDNA and D1/D2 domain of 26S rDNA, these species are located in the Bullera variabilis (Bulleribasidum) cluster in Hymenomycetes. They are described as Bullera begoniae sp. nov. and Bullera setariae sp. nov., respectively.     

Candida kazuoi sp. nov. and Candida hasegawae sp. nov., two new species of ascomycetous anamorphic yeasts isolated from insect frass in Thailand

Two strains of anamorphic yeasts isolated from insect frass collected in southern Thailand were assigned to the genus Candida based on the conventional taxonomic criteria used for yeast classification. In the phylogenetic tree based on the D1/D2 domain of the 26S rDNA, these strains are distant from the known species of yeasts and considered to represent two different new species. They are named Candida kazuoi sp. nov. and Candida hasegawae sp. nov.     

Candida alocasiicola sp. nov., Candida hainanensis sp. nov., Candida heveicola sp. nov. and Candida musiphila sp. nov., novel anamorphic, ascomycetous yeast species isolated from plants

In a taxonomic study on the ascomycetous yeasts isolated from plant materials collected in tropical forests in Yunnan and Hainan Provinces, southern China, four strains isolated from tree sap (YJ2E(T)) and flowers (YF9E(T), YWZH3C(T) and YYF2A(T)) were revealed to represent four undescribed yeast species. Molecular phylogenetic analysis based on the large subunit (26S) rRNA gene D1/D2 domain sequences showed that strain YJ2E(T) was located in a clade together with Candida haemulonii and C. pseudohaemulonii. Strain YF9E(T) was most closely related to C. azyma and strain YWZH3C(T) to C. sorbophila and C. spandovensis. Strain YYF2A(T) was clustered in a clade containing small-spored Metschnikowia species and related anamorphic Candida species. The new strains differed from their closely related described species by more than 10% mismatches in the D1/D2 domain. No sexual states were observed for the four strains on various sporulation media. The new species are therefore assigned to the genus Candida and described as Candida alocasiicola sp. nov. (type strain, YF9E(T) = AS 2.3484(T) = CBS 10702(T)), Candida hainanensis sp. nov. (type strain, YYF2A(T) = AS 2.3478(T) = CBS 10696(T)), Candida heveicola sp. nov. (type strain, YJ2E(T) = AS 2.3483(T) = CBS 10701(T)) and Candida musiphila sp. nov. (type strain, YWZH3C(T) = AS 2.3479(T) = CBS 10697(T)).     

Candida easanensis sp. nov., Candida pattaniensis sp. nov. and Candida nakhonratchasimensis sp. nov., three new species of yeasts isolated from insect frass in Thailand

Six strains of anamorphic yeasts isolated from insect frass collected in several regions of Thailand were assigned to the genus Candida based on the conventional taxonomic criteria used for yeast classification. These strains have Q-7 as the major ubiquinone and are suggested to have close relationships to the genus Pichia. Three strains, ST-225, ST-228 and ST-229, have identical nucleotide sequences in the D1/D2 domain of 26S rDNA and are closely related to Pichia japonica, but differ by six nucleotides (1.1% ) from this species. These three strains are considered to represent a single new species, which is described as Candida easanensis sp. nov. Two strains, ST-311 and ST-320, have identical sequences in the D1/D2 domain and resemble Pichia veronae and Pichia fabianii but differ from them by nine nucleotides (1.6%) in D1/D2 sequences. The two strains are described as Candida pattaniensis sp. nov. The remaining strain, ST-37, is related to Pichia americana and Pichia bimundalis but differs by six(1.1%) and seven (1.2%) nucleotides from these species, respectively. This strain is described as Candida nakhonratchasimensis sp. nov.     

Ogataea populialbae sp. nov., a yeast species from white poplar

During a survey of methylotrophic yeasts in natural habitats in Hungary, the yeast community associated with the exudates of white poplar ( Populus alba ) was found to be unique among the tree exudates hitherto investigated. Nineteen methanol-assimilating yeast strains representing an undescribed ascomycetous species were isolated from tree exudates of P. alba collected at different locations in Hungary. Analysis of the D1/D2 large subunit rRNA gene sequences placed the strains in the Ogataea clade and the new species is described as Ogataea populialbae . The type culture is NCAIM Y.01853^T (CBS 11363, NRRL Y-48632).