Pichia kurtzmaniana f.a. sp. nov., with the transfer of eight Candida species to Pichia.

Three yeast strains belonging to the ascomycetous yeast genus Pichia were isolated from two soil samples from Yunnan and Guizhou provinces and a marine water sample from Liaoning province, PR China. Phylogenetic analyses based on the sequences of the D1/D2 domains of the large subunit(LSU) rRNA gene and the internal transcribed spacer (ITS) region indicate that these three strains, together with 12 additional strains isolated from various substrates collected in different regions or countries of the world, represent a novel species of the genus Pichia, for which the name Pichia kurtzmaniana sp. nov. (holotype: strain CGMCC 2.7213) is proposed. The novel species differs from its close relatives Candida californica by eight (1.5 %) and 26 (11.1 %) mismatches in the D1/D2 domains and the ITS region, respectively; and from Pichia chibodasensis by 11 (2.1 %) and 20 (8.7 %) mismatches in the D1/D2 domains and the ITS region, respectively. In addition, eight Candida species which belong to the Pichia clade are transferred to the genus Pichia, resulting in the proposal of the following new combinations: Pichia cabralensis comb. nov., Pichia californica comb. nov., Pichia ethanolica comb. nov., Pichia inconspicua comb. nov., Pichia phayaonensis comb. nov., Pichia pseudolambica comb. nov., Pichia rugopelliculosa comb. nov., and Pichia thaimueangensis comb. nov.

Vishniacozyma pseudocarnescens sp. nov., a new anamorphic tremellomycetous yeast species.

Three strains belonging to the basidiomycetous yeast genus Vishniacozyma were isolated from marine water samples collected from intertidal zones in Liaoning province, northeast China. Phylogenetic analyses based on the sequences of the small subunit (SSU) ribosomal DNA (rDNA), the D1/D2 domain of the large subunit (LSU) ribosomal DNA (rDNA), the internal transcribed spacer region (ITS), the two subunits of DNA polymerase II (RPB1 and RPB2), the translation elongation factor 1-α (TEF1), and the mitochondrial gene cytochrome b (CYTB) showed that these strains together with 20 strains from various geographic and ecological origins from other regions of the world represent a novel species in the genus Vishniacozyma. We propose the name Vishniacozyma pseudocarnescens sp. nov. (holotype CGMCC 2.6457) for the new species, which differs phenotypically from its close relatives V. carnescens, V. tephrensis, and V. victoriae by its ability to grow at 30 °C and on 50 % (w/v) glucose-yeast extract agar.

Fungal-Algal Association Drives Lichens' Mutualistic Symbiosis: A Case Study with Trebouxia-Related Lichens.

Biotic and abiotic factors influence the formation of fungal-algal pairings in lichen symbiosis. However, the specific determinants of these associations, particularly when distantly related fungi are involved, remain poorly understood. In this study, we investigated the impact of different drivers on the association patterns between taxonomically diverse lichenized fungi and their trebouxioid symbiotic partners. We collected 200 samples from four biomes and identified 41 species of lichenized fungi, associating them with 16 species of trebouxioid green algae, of which 62% were previously unreported. The species identity of both the fungal and algal partners had the most significant effect on the outcome of the symbiosis, compared to abiotic factors like climatic variables and geographic distance. Some obviously specific associations were observed in the temperate zone; however, the nestedness value was lower in arid regions than in cold, polar, and temperate regions according to interaction network analysis. Cophylogenetic analyses revealed congruent phylogenies between trebouxioid algae and associated fungi, indicating a tendency to reject random associations. The main evolutionary mechanisms contributing to the observed phylogenetic patterns were "loss" and "failure to diverge" of the algal partners. This study broadens our knowledge of fungal-algal symbiotic patterns in view of Trebouxia-associated fungi.

Cystofilobasidium josepaulonis sp. nov., a novel basidiomycetous yeast species.

A yeast strain belonging to the basidiomycetous yeast genus Cystofilobasidium was isolated from a marine sediment sample collected in an intertidal zone in Shandong province, PR China. The results of phylogenetic analyses based on sequences of the D1/D2 domain of the 26S ribosomal RNA gene and the internal transcribed spacer (ITS) region indicate that this strain, together with three other strains isolated from basal ice collected in Norway, the gut of an insect and an alga collected in Russia, represent a novel species of the genus, for which the name Cystofilobasidium josepaulonis sp. nov. (holotype strain CGMCC 2.6672T) is proposed. The novel species differs from the known species of the genus Cystofilobasidium by 1.7 %-4.1 and 11.3 %-17.1 % mismatches in the D1/D2 domain and the ITS region, respectively. This species forms teliospores on potato dextrose agar (PDA) and 10 % V8 juice agar, but teliospore germination with basidia was not observed.

Yeast Diversity in the Qaidam Basin Desert in China with the Description of Five New Yeast Species.

The Qaidam Basin is the highest and one of the largest and driest deserts on Earth. It is considered a mars analog area in China. In contrast to numerous studies concerning its geology, geophysical, and chemistry, relatively few studies have reported microbial diversity and distribution in this area. Here, we investigated culturable yeast diversity in the northeast Qaidam Basin. A total of 194 yeast strains were isolated, and 12 genera and 21 species were identified, among which 19 were basidiomycetous yeasts. Naganishia albida, N. adeliensis, and Filobasidium magnum were the three most dominant species and were distributed in thirteen samples from eight locations. Five new species (Filobasidium chaidanensis, Kondoa globosum, Symmetrospora salmoneus, Teunia nitrariae, and Vishniacozyma pseudodimennae) were found and described based on ITS and D1D2 gene loci together with phenotypic characteristics and physiochemical analysis. Representative strains from each species were chosen for the salt-tolerant test, in which species showed different responses to different levels of NaCl concentrations. Further, the strain from soil can adapt well to the higher salt stress compared to those from plants or lichens. Our study represents the first report of the yeast diversity in the Qaidam Basin, including five new species, and also provides further information on the halotolerance of yeasts from the saline environment in mars analog.

Four new species of Tremella (Tremellales, Basidiomycota) based on morphology and DNA sequence data.

In the present study, a total of 33 Tremella specimens in China were collected and examined using molecular phylogenetic analysis based on a combined sequence dataset of the nuc rDNA internal transcribed spacer (ITS) region and nuc 28S rDNA D1/D2 domain in conjunction with the morphological characters. Four new species, namely Tremellabasidiomaticola, T.cheejenii, T.erythrina, and T.salmonea, are newly described based on their distinct phylogenetic relationships and the comparison of morphological characters with known Tremella species. Our results indicate a high species diversity of Tremella waiting to be discovered.

Kondoa gutianensis f.a. sp. nov., a novel ballistoconidium-forming yeast species isolated from plant leaves.

Two strains, GT-165T and GT-261, isolated from plant leaves collected from Gutian Mountain in Zhejiang province in China were identified as a novel species of the genus Kondoa by the sequence analysis of the internal transcribed spacer (ITS) region, the D1/D2 domains of the large subunit of rRNA (LSU rRNA) and the RNA polymerase II second largest subunit (RPB2), complemented by physiological tests. Phylogenetic analysis based on the concatenated sequences of ITS, D1/D2 and RPB2 showed that the closest known relatives of the new species are three undescribed Kondoa species and Kondoa thailandica. The ITS and D1/D2 sequences of the new species differ from the closely related species by 11-22% and 2-9%, respectively. The name Kondoa gutianensis f.a. sp. nov. (MB 820648, holotype = CGMCC 2.5703T; isotype: CBS 14811T = CGMCC 2.5703T) is proposed to accommodate the new taxon.

Heitmania gen. nov., a new yeast genus in Microbotryomycetes, and description of three novel species: Heitmania litseae sp. nov., Heitmania castanopsis sp. nov. and Heitmania elacocarpi sp. nov.

Nine anamorphic yeast strains isolated from various plant leaves collected in southern China were phylogenetically characterized based on sequences of the internal transcribed spacer (ITS) region, the D1/D2 domains of the large subunit (LSU) rRNA gene, the small subunit (SSU) rRNA gene, the two subunits of the RNA polymerase II gene (RPB1 and RPB2) and the translation elongation factor 1-α (TEF1). Phylogenetic analysis of the combined sequences of the six genes showed that the new strains formed a distinct clade in the class Microbotryomycetes but could not be assigned to any of the existing genera, families or orders of the class. Three separate groups were consistently resolved from the nine new strains based on the combined sequences of the six genes and single gene sequences of ITS, RPB1, RPB2 and TEF1. The results suggest that the nine yeast strains compared represent three novel species in a novel genus. The names Heitmania gen. nov. (MycoBank registration number MB819987), Heitmania litseae sp. nov. (MB820112, type strain CGMCC 2.5697T=CBS 14756T), Heitmania castanopsis sp. nov. (MB819988, CGMCC 2.5698T=CBS 14750T) and Heitmania elacocarpi sp. nov. (MB820113, CGMCC 2.5695T=CBS 14752T) are proposed for the new taxa.

Intragenomic polymorphism and intergenomic recombination in the ribosomal RNA genes of strains belonging to a yeast species Pichia membranifaciens.

A concerted evolution model has been proposed to explain the observed lack of sequence variation among the multiple ribosomal RNA (rRNA) gene copies in many different eukaryotic species. Recent studies on the level of intragenomic variations in the rRNA gene repeats of fungi resulted in controversial conclusions. In this study, we clearly showed that significant polymorphisms of the internal transcribed spacers (ITS1 and ITS2) of ribosomal DNA (rDNA) exist within the genome of a strain of the yeast species Pichia membranifaciens. More interestingly, we showed that the intragenomic ITS sequence polymorphisms were formed by intergenomic rDNA recombination among different P. membranifaciens strains with significantly different ITS sequences. Intergenomic rDNA recombination was also responsible for the diversification of rDNA sequences in different strains of the species. After the events bring together different rDNA types in individual genomes of the P. membranifaciens strains compared, rDNA sequence heterogeneity has remained in the genome of one but eliminated by homogenisation in the genomes of other strains. Our findings show new clue for further investigation on the mechanism of concerted evolution of rRNA genes in eukaryotes.

Derxomyces amylogenes sp. nov., Derxomyces bambusicola sp. nov. and Derxomyces corylopsis sp. nov., three ballistoconidium-forming yeast species isolated from subtropical plant leaves.

Among ballistoconidium-forming yeast strains isolated from various plant leaves collected from subtropical forests in eastern and central China, four strains forming cream to yellowish coloured colonies were revealed to represent three novel Derxomyces species by conventional and molecular characterization. Phylogenetic analysis based on combined sequences of the internal transcribed spacer (ITS) and 26S rRNA gene D1/D2 domain showed that strains GT-753 and ZJJ-890T were conspecific and closely related to Derxomyces boninensis, Derxomyces mrakii and Derxomyces qinlingensis. Strain ZJJ-394T was basal to the branch formed by Derxomyces komagatae, Derxomyces pseudoschimicola and Derxomyces schimicola with strong bootstrap support. Strain GT-475T was closely related to Derxomyces linzhiensis. The strains differed significantly from their close relatives in D1/D2 and ITS sequences and in physiological criteria. Three novel species are proposed: Derxomyces amylogenes sp. nov. (type strain ZJJ-890T=CGMCC 2.4407T=CBS 12233T), Derxomyces bambusicola sp. nov. (type strain GT-475T=CGMCC 2.4411T=CBS 12234T) and Derxomyces corylopsis sp. nov. (type strain ZJJ-394T=CGMCC 2.4409T=CBS 12259T).