RESULTS:

Three strains of a novel yeast species were isolated from rotting wood in the Xishuangbanna Tropical Rainforest Yunnan Province PR China. Sequence analysis of the D1/D2 domains of the large subunit rRNA gene and the internal transcribed spacer (ITS) regions showed that the novel species represents a member of the genus Saturnispora. It differed from its closest known species Saturnispora sekii CBS 10931T by 1.3 % nucleotide substitutions in the D1/D2 domains and by 2.2 % nucleotide substitutions in the ITS regions respectively. In contrast to Saturnispora sekii the novel yeast species was unable to assimilate glycerol dl-lactate succinate and citrate and grow at 37 °C. The name Saturnispora galanensis sp. nov. is proposed to accommodate these strains with NYNU 1797 as the holotype.

Seven strains representing two novel yeast species were isolated from rotting wood in Henan and Yunnan Provinces PR China. The results of phylogenetic analysis based on the D1/D2 domains of the large subunit (LSU) rRNA gene revealed that these two species are members of the genus Kodamaea although the formation of ascospores was not observed. Kodamaea neixiangensis f.a. sp. nov. (type strain NYNU 167139T=CICC 33170T=CBS 14699T) formed a clade with Candida kaohsiungensis and Candida hsintzibuensis from which it differed by 10–16 substitutions in the D1/D2 domain. The ITS sequences of K. neixiangensis sp. nov. differed by 27 substitutions from those of the type strain of C. kaohsiungensis. The most closely related species with a validly published name to Kodamaea jinghongensis f.a. sp. nov. (type strain NYNU 167162T=CICC 33171T=CBS 14700T) was Candida fukazawae but this differed by 14 substitutions in the D1/D2 domain and by 15 substitutions in the ITS region.

Two strains representing a novel species of the genus Saturnispora were isolated from rotting wood samples collected in an Atlantic Rainforest site in Brazil. Analyses of the sequences of the D1/D2 domains of the rRNA gene showed that this novel species belongs to a subclade in the Saturnispora clade formed by Saturnispora sanitii Saturnispora sekii Saturnispora silvae and Saturnispora suwanaritii. The novel species differed in D1/D2 sequences by 60 or more nucleotide substitutions from these species. The strains produced asci with one to four hemispherical ascospores. A novel species named Saturnispora bothae sp. nov. is proposed to accommodate these isolates. The type strain is UFMG-CM-Y292T (=CBS 13484T). The MycoBank number is MB 817127.

Five ascosporogenous yeast strains related to the genus Kazachstania were isolated. Two strains (CLIB 1764T and CLIB 1780) were isolated from French sourdoughs; three others (UFMG-CM-Y273T UFMG-CM-Y451 and UFMG-CM-Y452) were from rotting wood in Brazil. The sequences of the French and Brazilian strains differed by one and three substitutions respectively in the D1/D2 large subunit (LSU) rRNA gene and the internal transcribed spacer (ITS). The D1/D2 LSU rRNA sequence of these strains differed by 0.5 and 0.7 % from Kazachstania exigua but their ITS sequences diverged by 8.1 and 8.3 % respectively from that of the closest described species Kazachstania barnettii. Analysis of protein coding sequences of RPB1 RPB2 and EF-1α distinguished the French from the Brazilian strains with respectively 3.3 6 and 11.7 % substitutions. Two novel species are described to accommodate these newly isolated strains: Kazachstania saulgeensis sp. nov. (type strain CLIB 1764T=CBS 14374T) and Kazachstania serrabonitensis sp. nov. (type strain UFMG-CM-Y273T=CLIB 1783T=CBS 14236T). Further analysis of culture collections revealed a strain previously assigned to the K. exigua species but having 3.8 % difference (22 substitutions and 2 indels) in its ITS with respect to K. exigua. Hence we describe a new taxon Kazachstania australis sp. nov. (type strain CLIB 162T=CBS 2141T) to accommodate this strain. Finally Candida humilis and Candida pseudohumilis are reassigned to the genus Kazachstania as new combinations. On the basis of sequence analysis we also propose that Candida milleri and Kazachstania humilis comb. nov. are conspecific.

Four yeast strains were isolated from rotting wood samples collected in the Baotianman Nature Reserve in Henan Province Central China. On the basis of sequence analysis of the D1/D2 domains of the large subunit rRNA gene and the internal transcribed spacer regions they were suggested to be two novel species of the genus Pichia. Pichia nanzhaoensis sp. nov. produces one to four spherical ascospores per ascus and is most closely related to Candida pseudolambica. Pichia paraexigua f.a. sp. nov. is a sister taxa to Pichia exigua but the formation of ascospores was not observed on various sporulation media. P. nanzhaoensis sp. nov. can weakly assimilate inulin whereas P. paraexigua sp. nov. can weakly assimilate d-glucosamine. The type strain of Pichia nanzhaoensis is NYNU 178136T (=CICC 33279T=CBS 15346T) and the type strain of Pichia paraexigua is NYNU 178135T (=CICC 33278T=CBS 15237T).

Six yeast isolates were obtained from rotting wood samples in Brazil and frass of a cerambycid beetle larva in French Guiana. Sequence analysis of the ITS-5.8S region and the D1/D2 domains of the large subunit rRNA gene showed that the isolates represent a novel species of Cyberlindnera. This novel species is related to Cyberlindnera japonica Cyberlindnera xylosilytica Candida easanensis and Candida maesa. It is heterothallic and produces asci with two or four hat-shaped ascospores. The name Cyberlindnera dasilvae sp. nov. is proposed to accommodate the novel species. The holotype of Cy. dasilvae is CBS 16129T and the designated paratype is CBS 16584. The MycoBank number is 838252. All isolates of Cy. dasilvae were able to convert xylose into xylitol with maximum xylitol production within 60 and 72 h. The isolates produced xylitol with values ranging from 12.61 to 31.79 g l−1 in yeast extract–peptone–xylose medium with 5% xylose. When the isolates were tested in sugarcane bagasse hydrolysate containing around 35–38 g l−1 d-xylose isolate UFMG-CM-Y519 showed maximum xylitol production.

Two strains of a novel ascomycetous yeast species were isolated from rotting wood samples collected in Jiuxi Mountain Forest Park in Yunnan Province southwest China. Both strains formed one or two spherical ascospores in persistent asci. Phylogenetic analysis of the concatenated sequences of the internal transcribed spacer (ITS) region (ITS1-5.8S–ITS2) and the D1/D2 domain of the large subunit rRNA gene revealed that the novel strains represented a phylogenetically distinct species belonging to the genus Torulaspora. This novel species differed from the type strains of the closest known species Torulaspora nypae and Torulaspora maleeae by 0.9 and 1.2 % nucleotide substitutions in the D1/D2 domain and 5.3 and 6 % nucleotide substitutions in the ITS region respectively. The novel species can also be distinguished from T. nypae and T. maleeae in terms of the ability to assimilate ribitol succinate and citrate and its ability to grow at 37 °C. The species name of Torulaspora jiuxiensis sp. nov. is proposed with holotype CBS 16004T (Mycobank MB 844535).

Two apiculate strains (NYNU 181072 and NYNU 181083) of a bipolar budding yeast species were isolated from rotting wood samples collected in Xishuangbanna Tropical Rainforest in Yunnan Province southwest PR China. On the basis of phenotypic characteristics and the results of phylogenetic analysis of the D1/D2 domain of the large subunit (LSU) rRNA internal transcribed spacer (ITS) region and the actin (ACT1) gene the two strains were found to represent a single novel species of the genus Hanseniaspora for which the name Hanseniaspora menglaensis f.a. sp. nov. (holotype CICC 33364T; MycoBank MB 847437) is proposed. In the phylogenetic tree H. menglaensis sp. nov. showed a close relationship with Hanseniaspora lindneri Hanseniaspora mollemarum Hanseniaspora smithiae and Hanseniaspora valbyensis. H. menglaensis sp. nov. differed from H. lindneri the most closely related known species by 1.2 % substitutions in the D1/D2 domain 2.5 % substitutions in the ITS region and 5.4 % substitutions in the ACT1 gene respectively. Physiologically H. menglaensis sp. nov. can also be distinguished from H. lindneri by its ability to assimilate d-gluconate.

Two yeast strains (NYNU 211162 and NYNU 211275) were isolated from rotting wood collected in the Baotianman Nature Reserve Henan Province central China. Phylogenetic analysis of the D1/D2 domain of the large subunit (LSU) rRNA gene and the internal transcribed spacer (ITS) region revealed that the strains represent a phylogenetically distinct species within the genus Spencermartinsiella. The name Spencermartinsiella henanensis fa. sp. nov. is proposed for this species with holotype CICC 33543T (Mycobank MB 851142). S. henanensis sp. nov. differed by only 3 nt (~0.5 %) substitutions from the closest known species S. europaea NCAIM Y.01817T in the D1/D2 domain but by 33 nt (~6 %) substitutions 34 nt (~3.8 %) substitutions 30 nt (~5.6 %) substitutions and 75 nt (~9.9 %) substitutions in the ITS region and the partial TEF1 COXII and RPB2 genes. Additionally S. henanensis sp. nov. can be physiologically distinguished from S. europaea by its ability to assimilate inulin inability to assimilate ethylamine and cadaverine and incapability of growth at 30 °C.

Nineteen isolates representing a candidate for a novel yeast species belonging to the genus Spencermartinsiella were recovered from rotting wood samples collected at different sites in Atlantic Rainforest and Amazonian Forest ecosystems in Brazil. Similarity search of the nucleotide sequence of the intergenic spacer (ITS)-5.8S and large subunit D1/D2 regions of the ribosomal gene cluster showed that this novel yeast is closely related to Spencermartinsiella cellulosicola. The isolates differ by four nucleotide substitutions in the D1/D2 domain and six substitutions and 31 indels in the ITS region from the holotype of S. cellulosicola. Phylogenomic analysis based on 1474 single-copy orthologues for a set of Spencermartinsiella species whose whole genome sequences are available confirmed that the novel species is phylogenetically close to S. cellulosicola. The low average nucleotide identity value of 83% observed between S. cellulosicola and the candidate species confirms that they are distinct. The novel species produced asci with hemispherical ascospores. The name Spencermartinsiella nicolii sp. nov. is proposed. The holotype is CBS 14238T. The MycoBank number is MB855027. Interestingly the D1/D2 sequence of the S. nicolii was identical to that of an uncultured strain of Spencermartinsiella causing systemic infection in a male adult crocodile (Crocodylus niloticus). The characterization of some virulence factors and antifungal susceptibility of S. nicolii isolates suggest that this yeast may be an opportunistic pathogen for animals including humans; the isolates grow at 37 °C.