Yamadazyma thunbergiae sp. nov., a novel yeast species associated with Bengal clock vines and soil in Okinawa, Japan.

Two strains, designated JCM 36746T and JCM 36749, were isolated from Bengal clock vine (Thunbergia grandiflora) and soil, respectively, in Okinawa, Japan. Analysis of the internal transcribed spacer (ITS) regions and D1/D2 domains of the large subunit rRNA gene sequences revealed identical sequences in both strains, indicating that they belong to the same species. Sequence analysis and physiological characterization identified these strains as representing a novel yeast species in the genus Yamadazyma. The sequence similarities of the concatenated ITS regions and D1/D2 domains indicated that JCM 36746T and JCM 36749 formed a well-supported distinct from closely related species belonging to the Yamadazyma clade, including Candida dendronema, C. diddensiae, C. germanica, C. kanchanaburiensis, C. naeodendra, C. vaughaniae, Y. akitaensis, Y. koratensis, Y. nakazawae, Y. philogaea, Y. phyllophila, Y. siamensis, Y. ubonensis, and three undescribed species, comprising Candida aff. naeodendra/diddensiae Y151, Candida sp. GE19S08, and Yamadazyma sp. strain NYNU 22830. The sequences of the D1/D2 domains and ITS regions differed in nucleotide substitutions by 1.51% and 2.57% or greater, respectively, from those of the previously described and undescribed related species. In addition, the physiological characteristics of the novel species were distinct from those of the closely related described species. On the basis of these findings, we propose the name Yamadazyma thunbergiae sp. nov. to classify this species within the genus Yamadazyma. The holotype used is JCM 36746T (ex-type strains CBS 18614 and NBRC 116657). The MycoBank accession number is MB 853823.

Spencermartinsiella nicolii sp. nov., a potential opportunistic pathogenic yeast species isolated from rotting wood in Brazil.

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.

Identification of Trichosporon yeast isolates from superficial infections in male patients from Central Brazil: an approach to the diversity of infections caused by this basidiomycete fungus.

The genus Trichosporon are currently recognized as opportunistic pathogens capable of causing superficial "white piedra" infections and potentially fatal invasive diseases (Trichosporonosis). In this work, determine the agent Trichosporon spp. isolated from the skin and appendages of a male population group in the Central-West region of Brazil. The isolates were analyzed by phenotypic, biochemical and molecular methods. Twenty-five strains of Trichosporon were isolated: T. asahii (18; 72%), followed by T. inkin (4; 16%) and T. faecale (3; 12%). Skin infections were the most affected (16; 64%) and the genitocrural region (13; 52%) was the most affected. The highest rate of isolation occurred between the ages of 21 and 30 years (9; 36%), with black men (African descent) (13; 52%) being the most affected by this type of superficial infection. After the advent of molecular techniques, more than 50 subspecies and about 16 different strains have been reported to cause human disease. In this series, three species of the genus Trichosporon of medical importance were highlighted, colonizing the genital and perigenital region of the studied population. For the identifications, classical phenotypic methods associated with genotypic identification were carried out, using molecular techniques based on the study of DNA; using sequence analysis of the DNA intergenic spacer region 1 (IGS1).

Kondoa tianchiensis f.a., sp. nov., an anamorphic yeast species isolated from plant leaves.

Two yeast strains, NYNU 236122 and NYNU 236180, were isolated from plant leaves collected in Tianchi Mountain, Henan Province, central China. Molecular phylogenetic analyses revealed the closest relatives of the strains are three described Kondoa species, Kondoa chamaenerii, Kondoa miscanthi, and Kondoa subrosea. Genetically, the isolated strains differed from the type strains of their three related species by 2-11(0.2-1.8%) base substitutions in the D1/D2 domain, 16-40 (2.6-5.6%) base mismatches in the internal transcribed spacer region, and more than 10.1% base substitutions in the partial RPB2 gene. Furthermore, the two strains differ physiologically from their closest related species, K. chamaenerii, in their ability to assimilate dl-lactate, nitrite, and l-lysine and their inability to assimilate nitrate. Additionally, they differ from K. miscanthi and K. subrosea in their ability to assimilate inulin, d-gluconate, and l-lysine. The species name of Kondoa tianchiensis f.a., sp. nov. is proposed with holotype CICC 33616T (Mycobank MB 853544).

Short Tandem Repeat Genotyping of Medically Important Fungi: A Comprehensive Review of a Powerful Tool with Extensive Future Potential.

Fungal infections pose an increasing threat to public health. New pathogens and changing epidemiology are a pronounced risk for nosocomial outbreaks. To investigate clonal transmission between patients and trace the source, genotyping is required. In the last decades, various typing assays have been developed and applied to different medically important fungal species. While these different typing methods will be briefly discussed, this review will focus on the development and application of short tandem repeat (STR) genotyping. This method relies on the amplification and comparison of highly variable STR markers between isolates. For most common fungal pathogens, STR schemes were developed and compared to other methods, like multilocus sequence typing (MLST), amplified fragment length polymorphism (AFLP) and whole genome sequencing (WGS) single nucleotide polymorphism (SNP) analysis. The pros and cons of STR typing as compared to the other methods are discussed, as well as the requirements for the development of a solid STR typing assay. The resolution of STR typing, in general, is higher than MLST and AFLP, with WGS SNP analysis being the gold standard when it comes to resolution. Although most modern laboratories are capable to perform STR typing, little progress has been made to standardize typing schemes. Allelic ladders, as developed for Aspergillus fumigatus, facilitate the comparison of STR results between laboratories and develop global typing databases. Overall, STR genotyping is an extremely powerful tool, often complimentary to whole genome sequencing. Crucial details for STR assay development, its applications and merit are discussed in this review.

Performance of common primary and chromogenic culture media for MALDI-TOF MS identification of clinically relevant yeasts.

Timely and accurate identification of yeasts is essential for adequate treatment, considering the increase in antifungal resistance of some species, particularly for C. auris. Current matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) manufacturer's protocol for identification of yeasts requires 24- to 72-h cultivation on Sabouraud dextrose media (SAB), but not some of the mainstay primary culture media used in mycology such as inhibitory mold agar (IMA), Mycosel, CHROMagar Candida Plus, and CHROMagar Candida. As culture media can influence MALDI-TOF MS identification results, this study evaluated the accuracy and performance of identification of clinically relevant yeasts on these first-line media using the VITEK-MS MALDI-TOF MS system.IMPORTANCEIn this study, a panel of 140 strains (21 species) was used to assess the performance of the selected media. Although not in the manufacturer's list of accepted media, IMA and chromogenic media are suitable for the identification of yeasts on the VITEK-MS systems. CHROMagar Candida Plus allowed the identification of 135/140 isolates tested after 24-h incubation similar to SAB reference media (137/140). Yeast isolates that grew on Mycosel selective media were also reliably identified by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. VITEK-MS system with IVD database V3.2 correctly identified C. auris strains to the species level on CHROMagar Candida Plus alleviating the need for subcultivation and reduced turnaround time (24-72 h) to identification for patient screening.

Molecular epidemiological investigation of Cryptococcus spp. isolated from cats in Japan using multi-locus sequence typing.

Cryptococcosis is an important fungal infection for both humans and cats, but molecular epidemiological studies on strains isolated from cats are limited. We conducted multi-locus sequence typing analysis and antifungal susceptibility testing of 14 Cryptococcus spp. strains from domestic cats in Japan and one strain isolated from a cat in Singapore. All 14 strains from domestic cats in Japan were identified as Cryptococcus neoformans molecular type VNI. The sequence types (STs) included eight cases of ST5, five cases of ST31, and one novel ST. VNI ST5 is the most frequently isolated strain in Japanese patients as well, while there are no records of VNI ST31 being isolated from Japanese patients. The Singaporean cat strain was identified as C. gattii VGIIb (C. deuterogattii), ST7. We compared these results with strains previously reported to have been isolated from cats. This comparison suggested that molecular types of Cryptococcus spp. isolated from cats may differ depending on the country. In the antifungal susceptibility testing of C. neoformans, one strain each exceeded the epidemiological cutoff value (ECV) for amphotericin B and 5-fluorocytosine, while two strains exceeded the ECV for fluconazole. This study reveals the molecular epidemiology of Cryptococcus spp. isolated from cats with cryptococcosis in Japan. It suggests that investigating Cryptococcus spp. carried by cats, which share close living environments with humans, may contribute to the health of both cats and human populations.

Cryptococcosis is an important fungal disease in both humans and cats. We genotyped strains isolated from cats with cryptococcosis in Japan. Our findings revealed that the most common genotype infecting both cats and humans in Japan is identical.

Molecular characterisation of Histoplasma capsulatum sensu lato from Ethiopian horses reveals two distinct phylogenetic clades.

Epizootic lymphangitis (EL) is a highly prevalent and contagious infectious disease affecting horses in many parts of Ethiopia caused by Histoplasma capsulatum sensu lato ('var. farciminosum'). In this study, 12 suspected isolates of H. capsulatum sensu lato or yeasts unidentified by conventional biochemical tests isolated from Ethiopian horses with EL were characterised by internal transcribed spacer sequencing. Six of the 12 isolates were identified to be members of H. capsulatum sensu lato and the other six were Pichia kudriavzevii (synonym: Candida krusei) (n = 3), Trichosporon asahii (n = 1), Geotrichum silvicola (n = 1) and Moesziomyces aphidis (n = 1), respectively. The six H. capsulatum sensu lato isolates were further characterised by multilocus sequence analysis. Four distinct gene loci (arf [462 bases], H-anti [410 bases], ole1 [338 bases] and tub1 [272 bases]) of these six isolates as well as those of two H. capsulatum sensu lato ('var. farciminosum') reference strains (ATCC 58332 and ATCC 28798) were polymerase chain reaction (PCR)-amplified and sequenced. Phylogenetic analyses of their concatenated nucleotide sequences showed that three of the isolates and the reference strain ATCC 58332 were identical and belonged to the Eurasia clade within Latin American (LAm) A (H. suramericanum), and those of the other three isolates and the reference strain ATCC 28798 were identical and belonged to the Africa clade. At least two distinct phylogenetic clades of H. capsulatum sensu lato were circulating in Ethiopian horses with EL. Advanced molecular technologies and bioinformatics tools are crucial for the accurate identification and typing of pathogens as well as the discovery of novel microorganisms in veterinary microbiology.

Using multilocus sequence analysis with four concatenated housekeeping gene loci, at least two distinct phylogenetic clades, namely Eurasia clade and Africa clade, of Histoplasma capsulatum sensu lato were confirmed to be circulating in Ethiopian horses with epizootic lymphangitis.

Cyberlindnera qingyuanensis f.a., sp. nov., a yeast species isolated from rotting wood.

Two yeast strains were isolated from rotting wood samples collected on Qingyuan Mountain, Fujian Province, PR China. Phylogenetic analysis, based on the concatenated sequences of the internal transcribed spacer (ITS) region and the D1/D2 domain of the large subunit rRNA gene, revealed that these two strains represent a novel species of the genus Cyberlindnera. The proposed name for this new species is Cyberlindnera qingyuanensis f.a., sp. nov. (holotype: GDMCC 2.300; ex-type: PYCC 9925) although the formation of ascospores was not observed. The novel species differs from its close relative Cyberlindnera galapagoensis by 7.7% sequence divergence (37 substitutions and seven indels) in the D1/D2 domain and 9.7% sequence divergence (42 substitutions and 34 indels) in the ITS region, respectively. Additionally, Cyb. qingyuanensis differs from its close relative Cyb. galapagoensis by its ability to grow in cellobiose, l-rhamnose, ribitol, galactitol, and dl-lactate, its growth at 37 °C, and its inability to ferment raffinose. The Mycobank number is MB 854693.

Inopinatus corneliae sp. nov. gen. nov. isolated from human skin: A newly discovered keratinophilic hyphomycete, order Onygenales.

BACKGROUND: Fungi clinically relevant to human skin comprise prevalent commensals and well-known pathogens. Only rarely human skin harbours fungi that evade identification. OBJECTIVE: To characterise an enigmatic specimen isolated from a skin lesion. METHODS: A comprehensive clinical and mycological workup including conventional methods for phenotypic characterisation and sequencing based on internal transcribed spacer (ITS) and large subunit (LSU) regions to infer a phylogenetic tree. RESULTS: Cultures on common solid media were macroscopically inconspicuous initially until mycelial tufts developed on the surface, notably on potato dextrose agar. Polymorphous chlamydospores were detected but no aleurospores and ascomata. At 26°C, the isolate grew on standard agars, plant materials and garden soil and utilised peptone, keratins, lipids, inulin, erythrocytes and cellulose. It also grew at 5°C and at 37°C. Nucleotide sequences of its ITS region showed 93% similarity to sequences of different Malbranchea species. The closest matches among LSU rRNA sequences were obtained with the genera Amauroascus, Arthroderma, Auxarthronopsis and Malbranchea (93%-95%). A combined phylogenetic analysis placed the fungus in a sister clade to Neogymnomycetaceae, classified as incertae sedis in Onygenales, on a large distance to either Diploospora rosea or 'Amauroascus' aureus. CONCLUSIONS: The genus Inopinatus gen. nov. (MB854685) with the species Inopinatus corneliae sp. nov. (MB854687) is introduced to accommodate our isolate (holotype: DSM 116806; isotypes: CBS 151104, IHEM 29063). Probably Inopinatus corneliae is a geophilic species that, although potentially harmful, was no relevant pathogen in our case. Its ecology, epidemiology and pathogenicity need to be further clarified.

A single-source nosocomial outbreak of Aspergillus flavus uncovered by genotyping.

During construction work (2017-2019), an increase in Aspergillus flavus infections was noted among pediatric patients, the majority of whom were receiving amphotericin B prophylaxis. Microsatellite genotyping was used to characterize the outbreak. A total of 153 A. flavus isolates of clinical and environmental origin were included. Clinical isolates included 140 from 119 patients. Eight patients were outbreak-related patients, whereas 111 were outbreak-unrelated patients from Danish hospitals (1994-2023). We further included four control strains. Nine A. flavus isolates were from subsequent air sampling in the outbreak ward (2022-2023). Typing followed Rudramurthy et al.(S. M. Rudramurthy, H. A. de Valk, A. Chakrabarti, J. Meis, and C. H. W. Klaassen, PLoS One 6:e16086, 2011, https://doi.org/10.1371/journal.pone.0016086). Minimum spanning tree (MST) and discriminant analysis of principal components (DAPC) were used for cluster analysis. DAPC analysis placed all 153 isolates in five clusters. Microsatellite marker pattern was clearly distinct for one cluster compared to the others. The same cluster was observed in an MST. This cluster included all outbreak isolates, air-sample isolates, and additional patient isolates from the outbreak hospital, previously undisclosed as outbreak related. The highest air prevalence of A. flavus was found in two technical risers of the outbreak ward, which were then sealed. Follow-up air samples were negative for A. flavus. Microsatellite typing defined the outbreak as nosocomial and facilitated the identification of an in-hospital source. Six months of follow-up air sampling was without A. flavus. Outbreak-related/non-related isolates were easily distinguished with DAPC and MST, as the outbreak clone's distinct marker pattern was delineated in both statistical analyses. Thus, it could be a variant of A. flavus, with a niche ability to thrive in the outbreak-hospital environment. IMPORTANCE: Aspergillus flavus can cause severe infections and hospital outbreaks in immunocompromised individuals. Although lack of isogeneity does not preclude an outbreak, our study underlines the value of microsatellite genotyping in the setting of potential A. flavus outbreaks. Microsatellite genotyping documented an isogenic hospital outbreak with an internal source. This provided the "smoking gun" that prompted the rapid allocation of resources for thorough environmental sampling, the results of which guided immediate and relevant cleaning and source control measures. Consequently, we advise that vulnerable patients should be protected from exposure and that genotyping be included early in potential A. flavus outbreak investigations. Inspection and sampling are recommended at any site where airborne spores might disperse from. This includes rarely accessed areas where air communication to the hospital ward cannot be disregarded.

Expansion of the multi-locus gene alignment approach to improve identification of the fungal species Alternaria alternata.

Alternaria alternata is part of a genus comprised of over 600 different species that occur all over the world and cause damage to humans, plants and thereby to the economy. Yet, even though some species are causing tremendous issues, the past years have shown that assigning newly found isolates to known species was rather inconsistent. Most identifications are usually done on the basis of spore morphology, chemotype and molecular markers. In this work we used strains isolated from the wild as well as commercial strains of the DSMZ (German collection of microorganisms and cell cultures) as a reference, to show, that the variation within the Alternaria alternata species is comparable to the variation between different species of the genus Alternaria in regards to spore morphology and chemotype. We compared the different methods of identification and discerned the concatenation of multiple molecular markers as the deciding factor for better identification. Up until this point, usually a concatenation of two or three traditional molecular markers was used. Some of those markers being stronger some weaker. We show that the concatenation of five molecular markers improves the likeliness of a correct assignment, thus a better distinction between the different Alternaria species.

Antifungal susceptibility and multilocus sequence typing (MLST) of Cryptococcus neoformans complex from HIV-associated cryptococcal meningitis patients in Manaus, Amazonas, Brazil.

Cryptococcus neoformans is primarily responsible for cases of cryptococcal meningitis in individuals with HIV/AIDS. This study evaluated the susceptibility of C. neoformans obtained from individuals with cryptococcal meningitis associated with HIV/AIDS in Manaus, Amazonas, Brazil, against the action of the antifungals amphotericin B, flucytosine, fluconazole, itraconazole and posaconazole and analyzed it using Multilocus Sequence Typing (MLST) in order to identify the Sequence Types (STs). We analyzed 30 isolates of C. neoformans, from 24 HIV/AIDS patients diagnosed with cryptococcosis from 2017 to 2019 in a reference hospital, in addition to 3 environmental isolates: 1 isolate obtained in the home of a patient and 2 isolates obtained from neighboring homes of patients. 86.6% (n = 26/30) of the clinical isolates were identified as C. neoformans VNI ST93, 6.6% (n = 2/30) as C. neoformans VNI ST5, 3.3% (n = 1/30) as C. neoformans VNI ST32 and 3.3% (n = 1/30) as C. neoformans VNB ST232. The environmental isolates were identified as C. neoformans VNI ST93 (n = 3/3). 96.6% (n = 29/30) isolates were sensitive to amphotericin B, though there was variation in the MIC. 60% (n = 18/30) presented a MIC above the proposed epidemiological cutoff values for one or more antifungals. All environmental isolates were sensitive to the tested antifungals. The MLST showed that there is an important relationship between C. neoformans VNI ST93 and individuals with HIV/AIDS, including in the environmental isolates analyzed. C. neoformans VNB ST232 was observed for the first time in Amazonas. Amphotericin B was proven to be the best drug, but fluconazole and posaconazole also showed relevant action.

Oral Candida albicans strain diversity and maintenance in HIV positive women in South Africa.

OBJECTIVE: This study investigated C. albicans strain diversity and maintenance in the oral cavity of HIV positive women over a 6 month period. STUDY DESIGN: C. albicans strains were isolated from 17 HIV positive women at Charlotte Maxeke Academic Hospital, Johannesburg at 3 intervals over a 6 month period. Strains were genotyped using ABC and Multilocus Sequence Typing (MLST) techniques. In the MLST technique, for each strain, a Diploid Sequence Type (DST) number was obtained. Using cluster analysis, an Unweighted Pair Group Method with Arithmetic Mean (UPGMA) dendrogram and a matrix of strain similarities were generated. Strains were also compared to the previous South African isolates documented in the MLST database. RESULTS: Ninety four percent of women carried the same ABC genotype for 6 months. MLST technique, showed that ten women (58.8%) carried the same DST at 2 visits, while seven (41.2%) carried different DST at all visits. Further analysis showed that 64.7% of women were recolonised with different strains and 35.3% carried the same strains of C. albicans with heterozygosity. A total of 40 diploid sequence types were identified of which 27 DSTs were unique to this study group that were added to the MLST database. Most of the strains were closely related to previously isolated strains from South Africa. CONCLUSION: Recolonization of the oral cavity with different strains and microevolution of the original strains of C. albicans can occur, which can be a potential problem for HIV patients, in whom highly virulent and drug resistant strains can emerge.

Unveiling Trichosporon austroamericanum sp. nov.: A Novel Emerging Opportunistic Basidiomycetous Yeast Species.

During an epidemiological survey, a potential novel species within the basidiomycetous yeast genus Trichosporon was observed. The clinical strain was obtained from a urine sample taken from a Brazilian kidney transplant recipient. The strain was molecularly identified using the intergenic spacer (IGS1) ribosomal DNA locus and a subsequent phylogenetic analysis showed that multiple strains that were previously reported by other studies shared an identical IGS1-genotype most closely related to that of Trichosporon inkin. However, none of these studies provided an in-depth characterization of the involved strains to describe it as a new taxon. Here, we present the novel clinically relevant yeast for which we propose the name Trichosporon austroamericanum sp. nov. (holotype CBS H-24937). T. austroamericanum can be distinguished from other siblings in the genus Trichosporon using morphological, physiological, and phylogenetic characters.

Exophiala amphawaensis sp. nov., a novel black yeast isolated from the gut of amphipods in Thailand.

The genus Exophiala is polymorphic, able to transition between yeast, hyphal and pseudohyphal forms. Species of the genus Exophiala are ubiquitous fungi that are distributed in various environments around the world. During a survey of fungal diversity in the gut of amphipods (Floresorchestia amphawaensis and undescribed Dogielinotid amphipods) from the Amphawa estuary, Samut Songkhram province, Thailand, five black yeast strains (DMKU-MG01, DMKU-MG07, DMKU-MG08, DMKU-HG10 and DMKU-FG04) were identified as representing a novel taxon on the basis of a combination of morphological and molecular phylogenetic features. The five strains did not produce filamentous hyphae or pseudohyphae. Only budding yeast cells were observed. On the basis of the phenotypic characteristics and the results of molecular analyses of the D1/D2 region of the large subunit (LSU) rRNA gene and the internal transcribed spacer (ITS) region, the five strains were identified as representing a novel species via applied nucleotide pairwise analysis. They differed from the most closely related species Exophiala alcalophiala by 3.54 % nucleotide substitutions (20 nucleotide substitutions in 572 bp) in the D1/D2 domains of the LSU rRNA gene. Moreover, the sequences of the ITS region of the five strains differed from those of the most closely related species E. alcalophiala, by 7.44-9.62 % nucleotide substitutions, and Exophiala halophiala, by 7.2-7.53 % nucleotide substitutions. The results of phylogenetic analyses based on the concatenated sequences of the ITS regions and the D1/D2 domains of the LSU rRNA gene confirmed that the five black yeast strains represented a single novel species of the genus Exophiala. In this study, Exophiala amphawaensis sp. nov. is proposed to accommodate these strains. The holotype is TBRC 15626T and the isotype is PYCC9020. The MycoBank accession number of the novel species is MB 851477.

Wickerhamiella lachancei f.a. sp. nov., a novel ascomycetous yeast species isolated from flowers of Lantana camara in India.

Two isolates representing a novel species of the genus Wickerhamiella were obtained in India from nectar of flowers of Lantana camara, an ornamental exotic species native to Central and South America. Phylogenetic analyses of the D1/D2 domain of the 26S large subunit (LSU) rRNA gene, internal transcribed spacer (ITS) region, and physiological characteristics, supported the recognition of the novel species, that we designate Wickerhamiella lachancei sp. nov (MycoBank no. MB851709), with MCC 9929T as the holotype and PYCC 10003T as the isotype. Considering pairwise sequence similarity, the type strain of the novel species differs from the type strain of the most closely related species, Wickerhamiella drosophilae CBS 8459T, by 16 nucleotide substitutions and two gaps (3.9 % sequence variation) in the D1/D2 region (560 bp compared) and 28 nucleotide substitutions and five gaps (7.22 % sequence variation) in the ITS region (444 bp compared).

Mrakia polaris sp. nov. and Mrakia amundsenii sp. nov. (Mrakiaceae, Cystofilobasidiales), two novel psychrophilic yeast species isolated from Arctic habitats.

Four yeast strains belonging to the basidiomycetous yeast genus Mrakia were isolated from diverse habitats in the Ny-Ålesund region (Svalbard, High Arctic): two from vascular plants, one from seawater and one from freshwater. Phylogenetic analysis, based on the ITS region and the D1/D2 domain of the 28S rRNA gene, identified these four strains as representing two novel species within the genus Mrakia. The names Mrakia polaris sp. nov. (MycoBank number: MB 852063) and Mrakia amundsenii sp. nov. (MycoBank number: MB 852064) are proposed. These two new species show distinct psychrophilic adaptations, as they exhibit optimal growth at temperatures between 10 and 15°C, while being unable to grow at 25°C. The holotype of M. polaris sp. nov. is CPCC 300345T, and the holotype of M. amundsenii sp. nov. is CPCC 300572T.

Wickerhamomyces corioli f.a., sp. nov., a novel yeast species discovered in two mushroom species.

Two yeast strains, designated as 19-39-3 and 19-40-2, obtained from the fruiting bodies of Trametes versicolor and Marasmius siccus collected in Yunwu Mountain Forest Park, PR China, have been identified as representing a novel asexual ascomycetous yeast species. From the results of phylogenetic analyses of the sequences of the D1/D2 domains of the large subunit (LSU) rRNA, small subunit (SSU) rRNA and translation elongation factor 1-α (TEF1) genes, it was determined that these strains represent a member of the genus Wickerhamomyces, with Wickerhamomyces alni and Candida ulmi as the closest relatives. The novel species exhibited 6.6 and 6.7% differences in the D1/D2 domains compared with W. alni and C. ulmi, respectively. Additionally, distinct biochemical and physiological differences were observed between the novel species and its related counterparts. No sexual reproduction was observed in these strains, leading to the proposal of the name Wickerhamomyces corioli f.a., sp. nov. for this newly discovered species.