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Recent studies have suggested that species of the Kazachstania genus may be interesting models of yeast domestication. Among these, Kazachstania barnettii has been isolated from various microbially transformed foodstuffs such as sourdough bread and kefir. In the present work, we sequence, assemble, and annotate the complete genomes of two K. barnettii strains: CLIB 433, being one of the two reference strains for K. barnettii that was isolated as a spoilage organism in soft drink, and CLIB 1767, recently isolated from artisan bread-making sourdough. Both assemblies are of high quality with N50 statistics greater than 1.3 Mb and BUSCO score greater than 99%. An extensive comparison of the two obtained genomes revealed very few differences between the two K. barnettii strains, considering both genome structure and gene content. The proposed genome assemblies will constitute valuable references for future comparative genomic, population genomic, or transcriptomic studies of the K. barnettii species., (© The Author(s) 2022. Published by Oxford University Press on behalf of the Society for Molecular Biology and Evolution.)

Geotrichum candidum is an environmental yeast, also found as part of the cheese surface microbiota, where it is important in the ripening of many traditional cheeses, such as Camembert. We have previously developed a Multi Locus Sequence Typing (MLST) scheme, which differentiated five clades, of which one contained only environmental isolates, two were composed almost entirely of dairy isolates, and two others contained a mixture of dairy, environmental, and miscellaneous food isolates. In order to provide a simple method to uniquely type G. candidum strains, and in addition to permit investigation of the population structure at a fine level, we describe here a molecular analysis using a set of twelve highly discriminating microsatellite-like markers. The present study consolidates the previously suggested division between dairy and environmental strains, and in addition distinguishes a specifically European group of environmental strains. This analysis permitted the discrimination of 72 genotypes from the collection of 80 isolates, while retaining the underlying meaningful phylogenetic relation between groups of strains.

Yeasts can have additional genetic information in the form of cytoplasmic linear dsDNA molecules called virus-like elements (VLEs). Some of them encode killer toxins. The aim of this work was to investigate the prevalence of such elements in D. hansenii killer yeast deposited in culture collections as well as in strains freshly isolated from blue cheeses. Possible benefits to the host from harboring such VLEs were analyzed. VLEs occurred frequently among fresh D. hansenii isolates (15/60 strains), as opposed to strains obtained from culture collections (0/75 strains). Eight new different systems were identified: four composed of two elements and four of three elements. Full sequences of three new VLE systems obtained by NGS revealed extremely high conservation among the largest molecules in these systems except for one ORF, probably encoding a protein resembling immunity determinant to killer toxins of VLE origin in other yeast species. ORFs that could be potentially involved in killer activity due to similarity to genes encoding proteins with domains of chitin-binding/digesting and deoxyribonuclease NucA/NucB activity, could be distinguished in smaller molecules. However, the discovered VLEs were not involved in the biocontrol of Yarrowia lipolytica and Penicillium roqueforti present in blue cheeses.

The unambiguous application of fungal names is important to communicate scientific findings. Names are critical for (clinical) diagnostics, legal compliance, and regulatory controls, such as biosafety, food security, quarantine regulations, and industrial applications. Consequently, the stability of the taxonomic system and the traceability of nomenclatural changes is crucial for a broad range of users and taxonomists. The unambiguous application of names is assured by the preservation of nomenclatural history and the physical organisms representing a name. Fungi are extremely diverse in terms of ecology, lifestyle, and methods of study. Predominantly unicellular fungi known as yeasts are usually investigated as living cultures. Methods to characterize yeasts include physiological (growth) tests and experiments to induce a sexual morph; both methods require viable cultures. Thus, the preservation and availability of viable reference cultures are important, and cultures representing reference material are cited in species descriptions. Historical surveys revealed drawbacks and inconsistencies between past practices and modern requirements as stated in the International Code of Nomenclature for Algae, Fungi, and Plants (ICNafp). Improper typification of yeasts is a common problem, resulting in a large number invalid yeast species names. With this opinion letter, we address the problem that culturable microorganisms, notably some fungi and algae, require specific provisions under the ICNafp. We use yeasts as a prominent example of fungi known from cultures. But viable type material is important not only for yeasts, but also for other cultivable Fungi that are characterized by particular morphological structures (a specific type of spores), growth properties, and secondary metabolites. We summarize potential proposals which, in our opinion, will improve the stability of fungal names, in particular by protecting those names for which the reference material can be traced back to the original isolate., (© 2021. The Author(s).)

Natural products are a reliable source of bioactive molecules and represent an industrial and pharmaceutical stake. Indeed, the model yeast species Saccharomyces cerevisiae is a well-known eukaryotic organism largely used as a biotechnological tool, but still a topical subject of study. In this work, the exploration of Saccharomyces cerevisiae is taken further through an untargeted metabolomics workflow. The aim is to enrich databases and bring new information about the standard S. cerevisiae strain in a given medium. Analytical methods and bioinformatics tools were combined in a high-throughput methodology useable to dereplicate many types of biological extracts and cartography secondary metabolites. Ultra-high-performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) analyses were carried out and spectral data were pre-processed to build molecular networks. Annotations were attributed to compounds through comparison with databases and manual investigation of networks. Ultra-high-resolution Fourier-transform ion cyclotron resonance mass spectrometry (FTICR-MS) brought additional information thanks to a higher dynamic range and enhanced UHPLC-MS/MS results by unveiling ambiguities and bringing accurate molecular formulae. Therefore, accurate and reliable annotated features resulted from the UHPLC-MS/MS data while FTICR-MS provided an overall cartography of metabolites thanks to van Krevelen diagrams. Various small molecules such as amino acids derivatives and indole alkaloids have been determined for the first time in this yeast. The complementarity of FTICR-MS and UHPLC-MS/MS for secondary metabolite annotation brought this new mapping of S. cerevisiae., Competing Interests: Declaration of Competing Interest The authors declare that they have no conflict of interest., (Copyright © 2020 Elsevier B.V. All rights reserved.)

Two strains (DMKU-GTCP10-8 and CLIB 1740) representing a novel anamorphic yeast species were isolated from a grease sample collected from a grease trap in Thailand and from an unidentified fungus collected in French Guiana, respectively. On the basis of phylogenetic analysis based on the combined D1 / D2 domain of the large subunit (LSU) rRNA gene and the internal transcribed spacer (ITS) region, Lachancea fermentati CBS 707 T was the closely related species with 12.8 % sequence divergence (70 nucleotide substitutions and three gaps in 571 nucleotides) and 28.1 % sequence divergence (93 nucleotide substitutions and 90 gaps in 651 nucleotides) in the D1/D2 domain of the LSU rRNA gene and the ITS region, respectively. Phylogenetic analysis based on the concatenated sequences of the five genes including the small subunit rRNA gene, the D1 / D2 domain of the LSU rRNA gene, the ITS region, translation elongation factor-1 alpha ( TEF1 ) and RNA polymerase II subunit 2 ( RPB2 ) genes confirmed that the two strains (DMKU-GTCP10-8 and CLIB 1740) were well-separated from other described yeast genera in Saccharomycetaceae. Hence, Savitreea pentosicarens gen. nov., sp. nov. is proposed to accommodate these two strains as members of the family Saccharomycetaceae. The holotype is S. pentosicarens DMKU - GTCP10-8 T (ex - type strain TBRC 12159 = PYCC 8490; MycoBank number 835044).

The extent of the diversity of yeasts in tropical rain forest and different environments from French Guiana was investigated. A total of 365 samples were collected from various substrates, such as plants, fruits and insects, at 13 locations, yielding 276 pure yeast isolates. Sequence analysis of the D1/D2 domains of the large subunit rRNA gene indicated that 210 isolates out of 276 belonged to 82 described species (67 Saccharomycotina, 14 Basidiomycota and 1 Pezizomycotina). In addition to these, a total of 54 Saccharomycotina isolates could not be assigned to a known species. These belonged to 14 genera and should be studied further from a taxonomic point of view. In addition, among the 43 Basidiomycotina isolates found, 12 could not be assigned to a known species. This report shows an unexpected biodiversity and indicates that oversea territories, such as French Guiana, constitute a largely unexplored reservoir for yeast diversity. Two Saccharomycotina strains, CLIB 1706 and CLIB 1725, isolated from an insect and from a fern respectively, were characterized further and were shown to belong to the Suhomyces clade on the basis of the rDNA sequence comparison. CLIB 1706 T rDNA sequences showed nine substitutions and three indels out of 556 bp (D1/D2 domains) and 32 substitutions and 12 indels out of 380 bp [internal transcribed spacer (ITS)] with that of the most closely related species Suhomyces guaymorum CBS 9823 T . CLIB 1725 T rDNA sequences presented 18 substitutions and one indel out of 549 bp (D1/D2 domains) and 48 substitutions and 11 indels out of 398 bp (ITS) with that of its closest relative Suhomyces vadensis CBS 9454 T . Two novel species of the genus Suhomyces were described to accommodate these two strains: Suhomyces coccinellae f.a. sp. nov. (CLIB 1706 T =CBS 14298 T ) and Suhomyces faveliae f.a. sp. nov. (CLIB 1725 T =CBS 14299 T ).

In order to assess the genetic diversity and population structure of indigenous S. cerevisiae from Côte d'Ivoire, a total of 170 strains were isolated from four traditional alcoholic beverages through nine regions. Microsatellite analysis performed at 12 loci revealed that strains of palm oil and raffia wine were genetically related, unlike those of tchapalo and ron wine which formed two s from palm oil wine and raffia wine were clearly inbred. In comparison with the European, North American, Asian and others West African populations, Ivorian population was well defined, although most of these strains were admixed. Among these strains, only isolates from raffia wine appeared to have alleles in common to all populations., (Copyright © 2019 Elsevier B.V. All rights reserved.)

Twelve strains of a novel yeast species were isolated from rotting wood, mushrooms and fruit samples in Brazil and French Guiana. Analysis of the sequences of the internal transcribed spacer region and the D1/D2 domains of the large subunit rRNA gene showed that the novel species belongs to the Kurtzmaniella clade. The novel species differed from its closest relative, Candida natalensis, by 12 substitutions in the D1/D2 sequences. The novel species could be distinguished from C. natalensis by its inability to assimilate cellobiose and salicin, and growth at 50 % (w/w) glucose. The name Kurtzmaniella hittingeri f.a., sp. nov. is proposed for the novel species. The type strain of K. hittingeri sp. nov. is CBS 13469 T (=UFMG CM-Y272 T ). The MycoBank number is 827183. We also propose the transfer of Candida fragi, Candida quercitrusa and Candida natalensis to the genus Kurtzmaniella as new combinations.

Microbial communities are essential for the maintenance and functioning of ecosystems, including fermented food ecosystems. The analysis of food microbial communities is mainly focused on lactic acid bacteria (LAB), while yeast diversity is less understood. Here, we describe the fungal diversity of a typical food fermented product, sourdough bread. The species diversity of 14 sourdoughs collected from bakeries located all over France was analyzed. Bakeries were chosen to represent diverse bakery practices and included bakers and farmer-bakers. Both non-culture-based (pyrosequencing of Internal Transcribed Spacer 1 amplicons) and culture-based methods were used. While both identification methods were in agreement regarding the dominant yeast species of each sourdough, the ITS1 metabarcoding analysis identified an increased number of fungal species in sourdough communities. Two third of the identified sequences obtained from sourdoughs were Saccharomycetales , mostly in the Kazachstania genus. No Saccharomycetales species was shared by all the sourdoughs, whereas five other fungal species, mainly known plant pathogens, were found in all sourdoughs. Interestingly, Saccharomyces cerevisiae , known as "baker's yeast," was identified as the dominant species in only one sourdough. By contrast, five Kazachstania species were identified as the dominant sourdough species, including one recently described Kazachstania species, Kazachstania saulgeensis and an undescribed Kazachstania sp. Sourdoughs from farmer-bakers harbored Kazachstania bulderi, Kazachstania unispora and two newly described Kazachstania species, while sourdough from bakers mostly carried Kazachstania humilis as the dominant species. Such yeast diversity has not been found in sourdoughs before, highlighting the need to maintain different traditional food practices to conserve microbial diversity.

Aims: To investigate the genotypic diversity and enzymatic activity of yeast flora isolated from spontaneous fermenting saps of various palm trees (Borassus aethiopum, Raphia hookeri, Elaeis guineensis) tapped for palm wines., Methods and Results: PCR-restriction fragment length polymorphism of ITS-5.8S rDNA combined to 26S rRNA gene and/or the partial ACT1 gene sequencing were applied for yeast characterization, and their enzymatic profiles assessed by using API ZYM kits. Thirteen genera and 23 species were identified, with the highest diversity (14 species) in raffia wine. Saccharomyces cerevisiae was dominant and common to all palm wines. Some potentially pathogenic yeasts were also isolated. The majority of tested strains displayed high amylo-peptidase, phosphatase, β-glucosidase and α-glucosidase activities and esterase activity., Conclusions: Diverse yeast species colonized palm wines, among which some were related to a specific type of wine and the majority of them have the ability to digest starch, sugar, protein or lipid., Significance and Impact of the Study: This study is a first step in understanding the significance of indigenous yeast flora of palm wines from Côte d'Ivoire. This knowledge is important as a tool for establishing new indigenous yeast collection; which could be used for the product quality improvement and as enzyme sources for biotechnological purposes., (© 2018 The Society for Applied Microbiology.)

Six yeast strains representing two novel Wickerhamiella species were isolated from plants and insects collected in Costa Rica, Brazil, and French Guiana. They belong to a subclade containing Wickerhamiella domercqiae and Wickerhamiella bombiphila, and differ by approximately 12 % in the D1/D2 sequences of the large subunit rRNA gene from these species. The intergenic spacer (ITS) regions of the two novel species differ by around 19 and 27 %, respectively, from those of W. domercqiae. The novel species exhibit 5 % divergence in the D1/D2 sequences among them (around 4 % in the ITS). The names Wickerhamiella dianesei f.a., sp. nov. and Wickerhamiella kurtzmanii f.a., sp. nov. are proposed to accommodate these species, for which a sexual cycle has not been observed. Wickerhamiella dianesei was isolated from the stingless bee, Trigona fulviventris, collected in an Asteraceae flower in Costa Rica, and from leaves of Sabicea brasiliensis (Rubiaceae) and a flower of Byrsonima crassifolia (Malpighiaceae) in Brazil. Wickerhamiellsa kurtzmanii was isolated from a flower of Ipomoea batatoides (Convolvulaceae) in Costa Rica, the surface of a fruit of B. crassifolia in Brazil, and flowers in French Guiana. The type strains are Wickerhamiella dianesei UWOPS 00-107.1 T (=CBS 14185=NRRL Y-63789; Mycobank number MB 827008) and Wickerhamiella kurtzmanii UWOPS 00-192.1 T (=CBS 15383=NRRL Y-63979; MB 827011).

Analysis of yeasts isolated from various biotopes in French Guiana led to the identification of two strains isolated from flowers and designated CLIB 1634 T and CLIB 1707 T . Comparison of the D1/D2 domain of the large subunit (LSU D1/D2) rRNA gene sequences of CLIB 1634 T and CLIB 1707 T to those in the GenBank database revealed that these strains belong to the Starmerella clade. Strain CLIB 1634 T was shown to diverge from the closely related Starmerella apicola type strain CBS 2868 T with a sequence divergence of 1.34 and 1.30 %, in the LSU D1/D2 rRNA gene and internal transcribed spacer (ITS) sequences respectively. Strain CLIB 1634 T and Candida apicola CBS 2868 T diverged by 3.81 and 14.96 % at the level of the protein-coding gene partial sequences EF-1α and RPB2, respectively. CLIB 1707 T was found to have sequence divergence of 3.88 and 9.16 % in the LSU D1/D2 rRNA gene and ITS, respectively, from that of the most closely related species Starmerella ratchasimensis type strain CBS 10611 T . The species Starmerella reginensis f.a., sp. nov. and Starmerella kourouensis f.a., sp. nov. are proposed to accommodate strains CLIB 1634 T (=CBS 15247 T ) and CLIB 1707 T (=CBS 15257 T ), respectively.

During a survey of the yeast community associated with the phylloplane of corn in Thailand, a basidiomycetous yeast strain belonging to the genus Papiliotrema was isolated. Analyses of the D1/D2 domains of the 26S (LSU) rRNA gene and complete ITS region supported the recognition of a novel species, for which the name Papiliotrema plantarum sp. nov. is proposed (type strain DMKU-CP801 T =CBS 15220 T =PYCC 7257 T ). Another strain of P. plantarum sp. nov., isolated in French Guiana, was found to be sexually compatible with the Thai isolate and mycelium with clamp connections, basidia and basidiospores were observed in culture. The basidial morphology of P. plantarum combined features previously observed for Papiliotrema bandonii and Papiliotrema fuscus, which represent the only sexual species hitherto known in the genus, i.e. transversely septate basidia, with sexual structures of the Tremella type.

Since food spoilage by yeasts causes high economic losses, fast and accurate identifications of yeasts associated with food and food-related products are important for the food industry. In this study the efficiency of the matrix assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS) to identify food related yeasts was evaluated. A CBS in-house MALDI-TOF MS database was created and later challenged with a blinded test set of 146 yeast strains obtained from food and food related products. Ninety eight percent of the strains were correctly identified with log score values>1.7. One strain, Mrakia frigida, gained a correct identification with a score value<1.7. Two strains could not be identified at first as they represented a mix of two different species. These mixes were Rhodotorula babjevae with Meyerozyma caribbica and Clavispora lusitaniae with Debaryomyces hansenii. After separation, all four species could be correctly identified with scores>1.7. Ambiguous identifications were observed due to two incorrect reference mass spectra's found in the commercial database BDAL v.4.0, namely Candida sake DSM 70763 which was re-identified as Candida oleophila, and Candida inconspicua DSM 70631 which was re-identified as Pichia membranifaciens. MALDI-TOF MS can distinguish between most of the species, but for some species complexes, such as the Kazachstania telluris and Mrakia frigida complexes, MALDI-TOF MS showed limited resolution and identification of sibling species was sometimes problematic. Despite this, we showed that the MALDI-TOF MS is applicable for routine identification and validation of foodborne yeasts, but a further update of the commercial reference databases is needed., (Copyright © 2017 Elsevier B.V. All rights reserved.)

Kazachstania saulgeensis is a recently described species isolated from French organic sourdough. Here, we report the high quality genome sequence of a monosporic segregant of the type strain of this species, CLIB 1764 T (= CBS 14374 T ). The genome has a total length of 12.9 Mb and contains 5326 putative protein-coding genes, excluding pseudogenes and transposons. The nucleotide sequences were deposited into the European Nucleotide Archive under the genome assembly accession numbers FXLY01000001-FXLY01000017.

During studies of the yeast diversity associated with rotting wood in Brazil and fruits, plants and insects in French Guiana, three strains of a new species were isolated. Analysis of the sequences of the internal transcribed spacer (ITS)-5.8S and D1/D2 domains of the large subunit of the rRNA gene showed that this species belongs to the genus Hyphopichia and its closest relative is Candida homilentoma. These species differ by 44 nucleotide substitutions in D1/D2 sequences. A new species Hyphopichia buzzinii f. a., sp. nov., is proposed to accommodate these isolates. The type strain of Hyphopichia buzzinii sp. nov. is CLIB 1739 T (=CBS 14300 T  = UFMG-CM-Y6121 T ; MycoBank number is MB 815609). In addition, we isolated 11 strains of C. homilentoma from rotting wood, leaf surfaces, and water bodies in Brazil, and these strains when crossed among one another and with the type strain (CBS 6312 T ) of this species, produced hat-shaped ascospores typical of the genus Hyphopichia. We describe the teleomorph of C. homilentoma as a new combination, Hyphopichia homilentoma comb. nov. (type strain CBS 6312 T ; MycoBank number is MB 820009). We also propose to transfer the other six Candida species of the Hyphopichia clade to this genus as new combinations. Hyphopichia homilentoma produced ethanol and xylitol from D-xylose whereas H. buzzinii was only able to convert this pentose to xylitol.

Geotrichum candidum is a ubiquitous yeast and an essential component in the production of many soft cheeses. We developed a multilocus sequence typing (MLST) scheme with five retained loci (NUP116, URA1, URA3, SAPT4 and PLB3) which were sufficiently divergent to distinguish 40 sequence types (STs) among the 67 G. candidum strains tested. Phylogenetic analyses defined five main clades; one clade was restricted to environmental isolates, three other clades included distinct environmental isolates and dairy strains, while the fifth clade comprised 34 strains (13 STs), among which all but two were isolated from milk, cheese or the dairy environment. These findings suggest an adaptation to the dairy ecosystems by a group of specialized European G. candidum strains. In addition, we developed a polymerase chain reaction inter-long terminal repeat scheme, a fast and reproducible random amplification of polymorphic DNA-like method for G. candidum, to type the closely related dairy strains, which could not be distinguished by MLST. Overall, our findings distinguished two types of dairy strains, one forming a homogeneous group with little genetic diversity, and the other more closely related to environmental isolates. Neither regional nor cheese specificity was observed in the dairy G. candidum strains analysed. This present study sheds light on the genetic diversity of both dairy and environmental strains of G. candidum and thus extends previous characterizations that have focused on the cheese isolates of this species. Copyright © 2016 John Wiley & Sons, Ltd., (Copyright © 2016 John Wiley & Sons, Ltd.)

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.

Two yeast strains that are members of the same species were isolated from different marine habitats, i.e. one from Mid-Atlantic Ridge ocean water samples located in the direct vicinity of black smokers near the Rainbow deep-sea hydrothermal vent and one from Brazilian marine water samples off the Ipanema beach. Strains CLIB 1964T and CLIB 1965 are anamorphic ascomycetous yeasts affiliated to the Yamadazyma clade of Saccharomycetales. Interestingly, these strains were phylogenetically and distinctly positioned into a group of species comprising all species of the genus Yamadazyma isolated from marine habitats including deep-sea hydrothermal vents, i.e.Candida atmosphaerica,C. spencermartinsiae,C. atlantica,C. oceani and C. taylorii. These strains differed significantly in their D1/D2 domain sequences of the LSU rRNA gene from the closely related species mentioned above, by 2.6, 3.0, 3.4, 3.8 and 6.0 %, respectively. Internal transcribed spacer region sequence divergence was also significant and corresponded to 4.6, 4.7, 4.7, 12.0 and 24.7 % with C. atlantica,C. atmosphaerica, C. spencermartinsiae,C. oceani and C. taylorii, respectively. Phenotypically, strains CLIB 1964T and CLIB 1965 could be distinguished from closely related species by their inability to assimilate l-sorbose. CLIB 1964T (=CBS 14301T=UBOCC-A-214001T) is the designated type strain for Yamadazyma barbieri sp. nov. The MycoBank number is MB 815884.

Raffia wine is a traditional alcoholic beverage produced in several African countries where it plays a significant role in traditional customs and population diet. Alcoholic fermentation of this beverage is ensured by a complex natural yeast flora which plays a decisive role in the quality of the final product. This present study aims to evaluate the distribution and the diversity of the yeast strains isolated in raffia wine from four sampling areas (Abengourou, Alépé, Grand-Lahou and Adzopé) in Côte d'Ivoire. Based on the D1/D2 domain of the LSU rDNA sequence analysis, nine species belonging to six genera were distinguished. With a percentage of 69.5 % out of 171 yeast isolates, Saccharomyces cerevisiae was the predominant species in the raffia wine, followed by Kodamaea ohmeri (20.4 %). The other species isolated were Candida haemulonii (4.1 %), Candida phangngensis (1.8 %), Pichia kudriavzevii (1.2 %), Hanseniaspora jakobsenii (1.2 %), Candida silvae (0.6 %), Hanseniaspora guilliermondii (0.6 %) and Meyerozyma caribbica (0.6 %). The molecular characterization of S. cerevisiae isolates at the strain level using the PCR-interdelta method revealed the presence of 21 profiles (named I to XXI) within 115 isolates. Only four profiles (I, III, V and XI) were shared by the four areas under study. Phenotypic characterization of K. ohmeri strains showed two subgroups for sugar fermentation and no diversity for the nitrogen compound assimilations and the growth at different temperatures.

The twenty-first century has brought new opportunities and challenges to yeast culture collections, whether they are long-standing or recently established. Basic functions such as archiving, characterizing and distributing yeasts continue, but with expanded responsibilities and emerging opportunities. In addition to a number of well-known, large public repositories, there are dozens of smaller public collections that differ in the range of species and strains preserved, field of emphasis and services offered. Several collections have converted their catalogues to comprehensive databases and synchronize them continuously through public services, making it easier for users worldwide to locate a suitable source for specific yeast strains and the data associated with these yeasts. In-house research such as yeast taxonomy continues to be important at culture collections. Because yeast culture collections preserve a broad diversity of species and strains within a species, they are able to make discoveries in many other areas as well, such as biotechnology, functional, comparative and evolution genomics, bioprocesses and novel products. Due to the implementation of the Convention of Biological Diversity (CBD) and the Nagoya Protocol (NP), there are new requirements for both depositors and users to ensure that yeasts were collected following proper procedures and to guarantee that the country of origin will be considered if benefits arise from a yeast's utilization. Intellectual property rights (IPRs) are extremely relevant to the current access and benefit-sharing (ABS) mechanisms; most research and development involving genetic resources and associated traditional knowledge will be subject to this topic. Copyright © 2016 John Wiley & Sons, Ltd., (Copyright © 2016 John Wiley & Sons, Ltd.)

Culture collections contain indispensable information about the microorganisms preserved in their repositories, such as taxonomical descriptions, origins, physiological and biochemical characteristics, bibliographic references, etc. However, information currently accessible in databases rarely adheres to common standard protocols. The resultant heterogeneity between culture collections, in terms of both content and format, notably hampers microorganism-based research and development (R&D). The optimized exploitation of these resources thus requires standardized, and simplified, access to the associated information. To this end, and in the interest of supporting R&D in the fields of agriculture, health and biotechnology, a pan-European distributed research infrastructure, MIRRI, including over 40 public culture collections and research institutes from 19 European countries, was established. A prime objective of MIRRI is to unite and provide universal access to the fragmented, and untapped, resources, information and expertise available in European public collections of microorganisms; a key component of which is to develop a dynamic Information System. For the first time, both culture collection curators as well as their users have been consulted and their feedback, concerning the needs and requirements for collection databases and data accessibility, utilised. Users primarily noted that databases were not interoperable, thus rendering a global search of multiple databases impossible. Unreliable or out-of-date and, in particular, non-homogenous, taxonomic information was also considered to be a major obstacle to searching microbial data efficiently. Moreover, complex searches are rarely possible in online databases thus limiting the extent of search queries. Curators also consider that overall harmonization-including Standard Operating Procedures, data structure, and software tools-is necessary to facilitate their work and to make high-quality data easily accessible to their users. Clearly, the needs of culture collection curators coincide with those of users on the crucial point of database interoperability. In this regard, and in order to design an appropriate Information System, important aspects on which the culture collection community should focus include: the interoperability of data sets with the ontologies to be used; setting best practice in data management, and the definition of an appropriate data standard.

The aim of this study was to assess potential candidate gene regions and corresponding universal primer pairs as secondary DNA barcodes for the fungal kingdom, additional to ITS rDNA as primary barcode. Amplification efficiencies of 14 (partially) universal primer pairs targeting eight genetic markers were tested across > 1 500 species (1 931 strains or specimens) and the outcomes of almost twenty thousand (19 577) polymerase chain reactions were evaluated. We tested several well-known primer pairs that amplify: i) sections of the nuclear ribosomal RNA gene large subunit (D1-D2 domains of 26/28S); ii) the complete internal transcribed spacer region (ITS1/2); iii) partial β -tubulin II (TUB2); iv) γ-actin (ACT); v) translation elongation factor 1-α (TEF1α); and vi) the second largest subunit of RNA-polymerase II (partial RPB2, section 5-6). Their PCR efficiencies were compared with novel candidate primers corresponding to: i) the fungal-specific translation elongation factor 3 (TEF3); ii) a small ribosomal protein necessary for t-RNA docking; iii) the 60S L10 (L1) RP; iv) DNA topoisomerase I (TOPI); v) phosphoglycerate kinase (PGK); vi) hypothetical protein LNS2; and vii) alternative sections of TEF1α. Results showed that several gene sections are accessible to universal primers (or primers universal for phyla) yielding a single PCR-product. Barcode gap and multi-dimensional scaling analyses revealed that some of the tested candidate markers have universal properties providing adequate infra- and inter-specific variation that make them attractive barcodes for species identification. Among these gene sections, a novel high fidelity primer pair for TEF1α, already widely used as a phylogenetic marker in mycology, has potential as a supplementary DNA barcode with superior resolution to ITS. Both TOPI and PGK show promise for the Ascomycota, while TOPI and LNS2 are attractive for the Pucciniomycotina, for which universal primers for ribosomal subunits often fail.

The evolutionary history of the characters underlying the adaptation of microorganisms to food and biotechnological uses is poorly understood. We undertook comparative genomics to investigate evolutionary relationships of the dairy yeast Geotrichum candidum within Saccharomycotina. Surprisingly, a remarkable proportion of genes showed discordant phylogenies, clustering with the filamentous fungus subphylum (Pezizomycotina), rather than the yeast subphylum (Saccharomycotina), of the Ascomycota. These genes appear not to be the result of Horizontal Gene Transfer (HGT), but to have been specifically retained by G. candidum after the filamentous fungi-yeasts split concomitant with the yeasts' genome contraction. We refer to these genes as SRAGs (Specifically Retained Ancestral Genes), having been lost by all or nearly all other yeasts, and thus contributing to the phenotypic specificity of lineages. SRAG functions include lipases consistent with a role in cheese making and novel endoglucanases associated with degradation of plant material. Similar gene retention was observed in three other distantly related yeasts representative of this ecologically diverse subphylum. The phenomenon thus appears to be widespread in the Saccharomycotina and argues that, alongside neo-functionalization following gene duplication and HGT, specific gene retention must be recognized as an important mechanism for generation of biodiversity and adaptation in yeasts.

Background: Yeasts belonging to the subphylum Saccharomycotina have been used for centuries in food processing and, more recently, biotechnology. Over the past few decades, these yeasts have also been studied in the interest of their potential to produce oil to replace fossil resources. Developing yeasts for massive oil production requires increasing yield and modifying the profiles of the fatty acids contained in the oil to satisfy specific technical requirements. For example, derivatives of medium-chain fatty acids (MCFAs, containing 6-14 carbons) are used for the production of biodiesels, cleaning products, lubricants and cosmetics. Few studies are available in the literature on the production of MCFAs in yeasts., Results: We analyzed the MCFA content in Saccharomyces cerevisiae grown in various conditions. The results revealed that MCFAs preferentially accumulated when cells were grown on synthetic media with a high C/N ratio at low temperature (23 °C). Upon screening deletion mutant strains for genes encoding lipid droplet-associated proteins, we found two genes, LOA1 and TGL3, involved in MCFA homeostasis. A phylogenetic analysis on 16 Saccharomycotina species showed that fatty acid profiles differed drastically among yeasts. Interestingly, MCFAs are only present in post-whole genome duplication yeast species., Conclusions: In this study, we produced original data on fatty acid diversity in yeasts. We demonstrated that yeasts are amenable to genetic and metabolic engineering to increase their MCFA production. Furthermore, we revealed that yeast lipid biodiversity has not been fully explored, but that yeasts likely harbor as-yet-undiscovered strains or enzymes that can contribute to the production of high-value fatty acids for green chemistry.

Ice from Arctic glaciers contains large populations of yeasts. We studied 38 isolates from this environment, which were initially identified as Debaryomyces sp. related to Debaryomyces hansenii by sequence analysis of the D1/D2 domains of 26S rDNA. An analysis of the distribution of mitochondrial DNA insertions in the nuclear genome showed that 25 of these isolates were related to, but distinct from, D. hansenii. Sequence analysis of the ACT1 gene of these 25 isolates revealed that they formed three different types of putative hybrids. In particular, 23 putative hybrids carried an ACT1 sequence identical to that of three Debaryomyces strains, CBS 790, CLIB 660, CLIB 949, previously classified as associated with D. hansenii and an ACT1 sequence of an undescribed taxon. The latter sequence displayed between 22 and 27 bp divergence (2.6-3.2 %) over 841 bp from sequences of closely related Debaryomyces sp., suggesting that this new taxon very likely represents a novel species for which no pure strain is available. Sequence comparisons of CBS 790, CLIB 660, and CLIB 949 with related Debaryomyces type strains also revealed an important sequence divergence. The putative hybrids described in this study could be differentiated from non-hybrid isolates and other Debaryomyces species on the basis of their use of a number of carbon sources.

Three yeast strains related to members of the genus Saccharomycopsis were isolated. One strain (CLIB 1310) was isolated from olive brines of fermented black olives in France and two strains (CLIB 1454 and CLIB 1455) were isolated from a plant in French Guiana. Sequence analyses based on the D1/D2 domains of the nuclear large subunit rRNA gene, small-subunit rRNA gene and partial EF-1α gene revealed that the strains represented two novel taxa exhibiting extensive sequence divergence from the previously described species of the genus Saccharomycopsis. Two novel species are described to accommodate these newly isolated strains: Saccharomycopsis olivae sp. nov. (type strain CLIB 1310(T) = CBS 12701(T)) and Saccharomycopsis guyanensis sp. nov. (type strain CLIB 1455(T) = CBS 12914(T) and strain CLIB 1454). Both strains CLIB 1454 and CLIB 1455(T) displayed identical sequences but differed in their ability to metabolize sorbitol and in their morphology on agar medium. Candida amapae, Candida lassensensis and Arthroascus babjevae belonging to the Saccharomycopsis clade, are reassigned to Saccharomycopsis as novel combinations., (© 2014 IUMS.)

Despite recommendations to release microbial resources to the community post-publication, the reality is far from satisfying. A workshop discussed the need for a coordinated and effective deposition policy for 'key' microbial strains and proposes a set of criteria to facilitate their deposition into public service collections. The majority of authors either contacted directly or during submission of manuscripts to several international, mainly European bacteriology journals agreed to this set of 'key strain' criteria and to the voluntarily deposition of resources into public resource centres.

Background: The industrially important yeast Blastobotrys (Arxula) adeninivorans is an asexual hemiascomycete phylogenetically very distant from Saccharomyces cerevisiae. Its unusual metabolic flexibility allows it to use a wide range of carbon and nitrogen sources, while being thermotolerant, xerotolerant and osmotolerant., Results: The sequencing of strain LS3 revealed that the nuclear genome of A. adeninivorans is 11.8 Mb long and consists of four chromosomes with regional centromeres. Its closest sequenced relative is Yarrowia lipolytica, although mean conservation of orthologs is low. With 914 introns within 6116 genes, A. adeninivorans is one of the most intron-rich hemiascomycetes sequenced to date. Several large species-specific families appear to result from multiple rounds of segmental duplications of tandem gene arrays, a novel mechanism not yet described in yeasts. An analysis of the genome and its transcriptome revealed enzymes with biotechnological potential, such as two extracellular tannases (Atan1p and Atan2p) of the tannic-acid catabolic route, and a new pathway for the assimilation of n-butanol via butyric aldehyde and butyric acid., Conclusions: The high-quality genome of this species that diverged early in Saccharomycotina will allow further fundamental studies on comparative genomics, evolution and phylogenetics. Protein components of different pathways for carbon and nitrogen source utilization were identified, which so far has remained unexplored in yeast, offering clues for further biotechnological developments. In the course of identifying alternative microorganisms for biotechnological interest, A. adeninivorans has already proved its strengthened competitiveness as a promising cell factory for many more applications.

A yeast strain was isolated from olive brines in a fermented black olive and olive oil manufacturing plant in the town of Nyons (France). On the basis of domains 1 and 2 (D1/D2) large subunit (LSU) rRNA gene and internal transcribed spacer (ITS) region sequence analyses, the strain CLIB 1303(T) was found to be closely related, but clearly distinct, from the three existing species of the genus Citeromyces: Citeromyces matritensis, Citeromyces siamensis and Citeromyces haiwaiiensis. Strain CLIB 1303(T) exhibited 6 bp, 7 bp and 12 bp divergences in the D1/D2 LSU rRNA gene with C. siamensis, C. matritensis and C. hawaiiensis, respectively. ITS region divergence amounted to more than 8 %, 4 % and 4.5 % with C. siamensis, C. matritensis and C. hawaiiensis, respectively, in addition to several indels. Like C. matritensis and C. siamensis strains, strain CLIB 1303(T) was shown to be halotolerant and osmotolerant. Phenotypically, strain CLIB 1303(T) can be distinguished from other species of the genus Citeromyces by its inability to assimilate trehalose. The strain CLIB 1303(T) (= CBS 12700(T)) was assigned to a novel species, Citeromyces nyonsensis sp. nov.

With the advances in sequencing techniques, identification of ascomycetous yeasts to the species level and phylogeny reconstruction increasingly require curated and updated taxonomic information. A specific database with nucleotide sequences of the most common markers used for yeast taxonomy and phylogeny and a user-friendly interface allowing identification, taxonomy and phylogeny of yeasts species was developed. By 1 September 2012, the YeastIP database contained all the described Saccharomycotina species for which sequences used for taxonomy and phylogeny, such as D1/D2 rDNA and ITS, are available. The database interface was developed to provide a maximum of relevant information and data mining tools, including the following features: (1) the blast n program for the sequences of the YeastIP database; (2) easy retrieval of selected sequences; (3) display of the available markers for each selected group of species; and (4) a tool to concatenate marker sequences, including those provided by the user. The concatenation tool allows phylogeny reconstruction through a direct link to the Phylogeny.fr platform. YeastIP is thus a unique database in that it provides taxonomic information and guides users in their taxonomic analyses. YeastIP facilitates multigenic analysis to encourage good practice in ascomycetous yeast phylogeny (URL: http://genome.jouy.inra.fr/yeastip.)., (© 2012 Federation of European Microbiological Societies. Published by Blackwell Publishing Ltd. All rights reserved.)

The hybrid nature of lager-brewing yeast strains has been known for 25 years; however, yeast hybrids have only recently been described in cider and wine fermentations. In this study, we characterized the hybrid genomes and the relatedness of the Eg8 industrial yeast strain and of 24 Saccharomyces cerevisiae/Saccharomyces kudriavzevii hybrid yeast strains used for wine making in France (Alsace), Germany, Hungary, and the United States. An array-based comparative genome hybridization (aCGH) profile of the Eg8 genome revealed a typical chimeric profile. Measurement of hybrids DNA content per cell by flow cytometry revealed multiple ploidy levels (2n, 3n, or 4n), and restriction fragment length polymorphism analysis of 22 genes indicated variable amounts of S. kudriavzevii genetic content in three representative strains. We developed microsatellite markers for S. kudriavzevii and used them to analyze the diversity of a population isolated from oaks in Ardèche (France). This analysis revealed new insights into the diversity of this species. We then analyzed the diversity of the wine hybrids for 12 S. cerevisiae and 7 S. kudriavzevii microsatellite loci and found that these strains are the products of multiple hybridization events between several S. cerevisiae wine yeast isolates and various S. kudriavzevii strains. The Eg8 lineage appeared remarkable, since it harbors strains found over a wide geographic area, and the interstrain divergence measured with a (δμ)(2) genetic distance indicates an ancient origin. These findings reflect the specific adaptations made by S. cerevisiae/S. kudriavzevii cryophilic hybrids to winery environments in cool climates.

Microbial food cultures have directly or indirectly come under various regulatory frameworks in the course of the last decades. Several of those regulatory frameworks put emphasis on "the history of use", "traditional food", or "general recognition of safety". Authoritative lists of microorganisms with a documented use in food have therefore come into high demand. One such list was published in 2002 as a result of a joint project between the International Dairy Federation (IDF) and the European Food and Feed Cultures Association (EFFCA). The "2002 IDF inventory" has become a de facto reference for food cultures in practical use. However, as the focus mainly was on commercially available dairy cultures, there was an unmet need for a list with a wider scope. We present an updated inventory of microorganisms used in food fermentations covering a wide range of food matrices (dairy, meat, fish, vegetables, legumes, cereals, beverages, and vinegar). We have also reviewed and updated the taxonomy of the microorganisms used in food fermentations in order to bring the taxonomy in agreement with the current standing in nomenclature., (Copyright © 2011 Elsevier B.V. All rights reserved.)

Among ascomycetous yeasts, the CTG clade is so-called because its constituent species translate CTG as serine instead of leucine. Though the biology of certain pathogenic species such as Candida albicans has been much studied, little is known about the life cycles of non-pathogen species of the CTG clade. Taking advantage of the recently obtained sequence of the biotechnological Millerozyma (Pichiasorbitophila) farinosa strain CBS 7064, we used MLST to better define phylogenic relationships between most of the Millerozyma farinosa strains available in public collections. This led to the constitution of four phylogenetic clades diverging from 8% to 15% at the DNA level and possibly constituting a species complex (M. farinosa) and to the proposal of two new species:Millerozyma miso sp. nov. CBS 2004(T) ( = CLIB 1230(T)) and Candida pseudofarinosa sp. nov.NCYC 386(T)( = CLIB 1231(T)). Further analysis showed that M. farinosa isolates exist as haploid and inter-clade hybrids. Despite the sequence divergence between the clades, secondary contacts after reproductive isolation were evidenced, as revealed by both introgression and mitochondria transfer between clades. We also showed that the inter-clade hybrids do sporulate to generate mainly viable vegetative diploid spores that are not the result of meiosis, and very rarely aneuploid spores possibly through the loss of heterozygosity during sporulation. Taken together, these results show that in this part of the CTG clade, non-Mendelian genetic exchanges occur at high rates through hybridization between divergent strains from distinct clades and subsequent massive loss of heterozygosity. This combination of mechanisms could constitute an alternative sexuality leading to an unsuspected biodiversity.

DNA sequencing has revolutionized yeast taxonomy. Although initially rDNA sequences proved to be universal and convenient for assigning phylogenetic relationships, it was eventually supplanted by multigene analysis, which provided more discriminating and robust results. This led to a new classification of the major yeast clades, which is still used as a reference today. More recently, the availability of a large number of complete genome sequences has given a new perspective on the molecular taxonomy of yeasts by providing a high number of genes to compare. It also highlighted an unexpected aspect of yeast genome evolution: the existence of interspecific hybrids outside of the industrial Saccharomyces clade. Together with the loss of heterozygosity in interspecific hybrids and a reduced sexuality leading to clonal propagation, this observation obliges us to reexamine the present concept of species. In parallel, the ongoing challenge is to find a universal molecular marker, to improve fast authentication and, if possible, phylogeny of yeasts. The future of yeast taxonomy will involve the sequencing of more genomes, thorough analysis of populations to obtain a good representation of the biodiversity and integration of these data into dedicated databases., (Copyright © 2011 Académie des sciences. Published by Elsevier SAS. All rights reserved.)