Yeast Genera Research Articles

Assessment of Fungal Contamination and Their Toxigenic Potential of Farmed Fish in Western Algeria

Fish and fish products have been documented as a major source of pathogens, with fungi playing a key role. In this paper, a survey was conducted to determine the presence of fungi in fish reared in various aquaculture farms in western Algeria, namely Nile Tilapia (Oreochromis niloticus), gilthead sea bream (Sparus aurata) and sea bass (Dicentrarchus labrax). The search for micromycetes was carried out on different parts of the body: skin and flesh, gills, and intestines. A total of 1937 fungal strains were revealed and divided into 10 genera of filamentous fungi, one genus of yeast, and other yeasts that have not yet been determined. Penicillium was the most common genus, representing 41.56% of the fungal population, fol-lowed by Rhodotorula (17.60%), and Aspergillus (15.95%). The greatest number of isolates was identified in the gills of gilthead sea bream, while the lowest number was isolated from sea bass intestines. Secondly, we sought to highlight the toxigenic potential of the fungal strains isolated, using the brine shrimp lethality test. Five of the fungal strains tested, belonging to the two genera Penicillium and Aspergillus, showed toxic potential for Artemia salina. The highest toxicities were observed mainly by strains of Aspergillus parasiticus (APAR001), Aspergillus terreus (ATER002), and Aspergillus niger (ANIG001) respectively. Penicillium chrysogenum (PCHR002) showed the lowest activity. These results confirm the infection of farmed fish by toxigenic fungal communities, which can present a real health hazard to consumers. Regular monitoring and compliance with fish health management practices are recommended.

Regional diversity and leaf microbiome interactions of the fungal maize pathogen Exserohilum turcicum in Switzerland: A metagenomic analysis.

The spread and adaptation of fungal plant pathogens in agroecosystems are facilitated by environmental homogeneity. Metagenomic sequencing of infected tissues allowed us to monitor eco-evolutionary dynamics and interactions between host, pathogen and plant microbiome. Exserohilum turcicum, the causal agent of northern corn leaf blight (NCLB) in maize, is distributed in multiple clonal lineages throughout Europe. To characterize regional pathogen diversity, we conducted metagenomic DNA sequencing on 241 infected leaf samples from the highly susceptible Swiss maize landrace Rheintaler Ribelmais, collected over 3 years (2016-2018) from an average of 14 agricultural farms within the Swiss Rhine Valley. All major European clonal lineages of E. turcicum were identified. Lineages differ by their mating types which indicates potential for sexual recombination and rapid evolution of new pathogen strains, although we found no evidence of recent recombination. The associated eukaryotic and prokaryotic leaf microbiome exhibited variation in taxonomic diversity between years and locations and is likely influenced by local weather conditions. A network analysis revealed distinct clusters of eukaryotic and prokaryotic taxa that correlates with the frequency of E. turcicum sequencing reads, suggesting causal interactions. Notably, the yeast genus Metschnikowia exhibited a strongly negative association with E. turcicum, supporting its known potential as biological control agent against fungal pathogens. Our findings show that metagenomic sequencing is a useful tool for analysing the role of environmental factors and potential pathogen-microbiome interactions in shaping pathogen dynamics and evolution, suggesting their potential for effective pathogen management strategies.

Kombucha with yam: Comprehensive biochemical, microbiological, and sensory characteristics

Consumer demand for functional foods has increased, helping to popularize and increase the consumption of Kombucha. Other substrates have been used together with tea to improve the functional and sensory properties of the beverage. Thus, this study evaluated the comprehensive biochemical, microbiological, and sensory characteristics of kombuchas fermented with green tea (Camellia sinensis) and different concentrations of yam (0, 10, and 20 % w/v). Based on pre-tests to detect the best concentration of yam in the beverage (10, 20, 30, and 40 %) and fermentation time (5, 7, and 14 days),the concentrations of 10 and 20 % of yam and five days of fermentation were selected through pH, °Brix, and sensory analysis. During the kombucha fermentation, there was a decrease in °Brix and pH. Sucrose, glucose, fructose, citric, and succinic acids were related to the beginning of fermentation, and lactic and acetic acids were more related to the end of fermentation in the treatment containing 20 % yam. The fermentation time did not change the color of the kombucha. Fatty acids, phenols, terpenoids, and alcohols were the volatile groups with the most compounds identified. Only two yeast genera were identified (Brettanomyces bruxellensis and Pichia membranifaciens), and bacteria of the genera Acetobacter, Lactobacillus, Pantoea, Pseudomonas, Azospirillum, and Enterobacter. The beverage control showed less turbidity and more clear. The fruity descriptor was more perceived in treatments with yam. However, the perception of the apple descriptor decreases as the yam concentration increases. The yam’s concentration alters the kombucha’s microbiota and sensory characteristics, mainly appearance and acidity. Kombucha fermentation using yam extract is viable, and the product is sensorially accepted. However, technological improvements, such as yam flour, could be made mainly for appearance and taste attributes.

The study of Candida albicans among Diabetic Patients attending some Selected Hospitals in Sokoto Metropolis

Candidiasis is an infection caused by the yeast genus Candida that lives in or on certain parts of the body, such as the gastrointestinal tract, the respiratory tract, the vagina, and even the skin. This study aimed to determine the prevalence of Candida albicans among diabetic patients attending some selected hospitals in metropolis. A total of 245 early-morning midstream urine samples were inoculated on SDA Saboraud dextrose agar. The isolates were identified using Gram staining, germ tube test, and KOH test. The prevalence of Candidiasis was 9. Females had a higher prevalence of 5.7% compared to males (3.7%) regarding gender (P = 0.247). Patients aged 30-34 years, 35-49 years, 40-44 years, 45-49 years and 50-54 years had prevalence of 0.0%, 0.4%, 0.4%, 0.4% and 8.0% respectively. Patients aged 55 years and above were the most infected in this study (7.3%) (P = 0.796). Due to high blood glucose levels and old age, regular clinic check-ups are highly recommended to prevent avoidable complications. These findings suggest that women are the most vulnerable compared to men. Therefore, it is necessary to continue evaluating the Candida albicans infection rate in diabetic patients in hospitals and the community.

Broadening the application of Yarrowia lipolytica synthetic biology tools to explore the potential of Yarrowia clade diversity.

Yeasts have established themselves as prominent microbial cell factories, and the availability of synthetic biology tools has led to breakthroughs in the rapid development of industrial chassis strains. The selection of a suitable microbial host is critical in metabolic engineering applications, but it has been largely limited to a few well-defined strains. However, there is growing consideration for evaluating strain diversity, as a wide range of specific traits and phenotypes have been reported even within a specific yeast genus or species. Moreover, with the advent of synthetic biology tools, non-type strains can now be easily and swiftly reshaped. The yeast Yarrowia lipolytica has been extensively studied for various applications such as fuels, chemicals, and food. Additionally, other members of the Yarrowia clade are currently being evaluated for their industrial potential. In this study, we demonstrate the versatility of synthetic biology tools originally developed for Y. lipolytica by repurposing them for engineering other yeasts belonging to the Yarrowia clade. Leveraging the Golden Gate Y. lipolytica tool kit, we successfully expressed fluorescent proteins as well as the carotenoid pathway in at least five members of the clade, serving as proof of concept. This research lays the foundation for conducting more comprehensive investigations into the uncharacterized strains within the Yarrowia clade and exploring their potential applications in biotechnology.

Innovation in Cocoa Fermentation: Evidence from Patent Documents and Scientific Articles

This review aims to analyze the technological and scientific applications regarding cocoa fermentation through a prospective study of patent documents and research articles. The Espacenet database was used as a patent research tool by searching both the IPC code “A23G1” and the terms “cocoa” and “ferment*”. A total of 130 documents were found—49 were related to the subject. The Scopus database was also searched for scientific articles using the terms “cocoa” and “fermentation”. A total of 812 articles were found—517 were related to the subject. Cocoa fermentation has not yet reached technological maturity, despite the growth in patent documents and scientific research observed in the last two decades. The creation of the Cacao of Excellence Program (2009), among others, has incentivized sustainability and quality in cocoa-producing countries. Brazil, Colombia, and Indonesia are leading with scientific publications in the last 5 years, despite the lack of patents filed. The United Kingdom, France, China, Canada, and Germany, despite not being cocoa-producing countries, are the main holders of the technology. Patent documents analyzed relate to food science, biotechnology, engineering, and chemistry. Microbial biotechnology has gained attention as a key factor to produce a higher-quality cocoa bean. Saccharomyces is the most frequent genus of yeast used as a starter culture in patent documents. Some patent documents propose the addition of fruits during cocoa fermentation, but a few scientific studies have been found on the matter. Overall, technological applications and scientific studies have focused on improving cocoa quality. The cocoa market is expected to increase significantly in the next few years, representing an opportunity to develop high-quality cocoa using novel fermentation techniques.

Obtention of pelleted Kluyveromyces marxianus CIDCA 9121 with immunomodulatory properties: Selection of protective agents using Plackett–Burman and Box–Behnken experimental designs

Probiotic yeasts are increasingly used in different animal production systems. Supply of feeding in the form of pellets provides productive advantages in several systems such as poultry production or aquaculture. The inclusion of viable yeast in the pellets has to overcome heat stress during palletization and also dehydration stress. We have worked with our previously characterized probiotic strain Kluyveromyces marxianus CIDCA 9121. We evaluated the resistance of this strain to a process dehydration and extrusion after pellet generation, conditions that were not analyzed for this genus of probiotic yeast. We determined the effects of different thermoprotective agents in order to maximize yeast viability over time and preservation of its probiotic traits. To this aim we used the single factor optimization method, Plackett-Burman central compound rotating design (P–B CCRD) and response surface methodology (RSM) for optimize survival conditions in a process performed at laboratory scale. We selected a combination of sucrose, maltose and maltodextrin and we have tested two different combinations of these agents in a pilot plant extrusion/dehydration process showing that one of them could increase yeast viability. Remarkably, we could observe that immunomodulatory capacity of this strain was not affected after dehydration in the presence of the different additives tested and subsequent rehydration, being the first report showing conservation of probiotic traits of K. marxianus strain upon pelleting opening new perspectives for product development.

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.

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.

Selenized non-Saccharomyces yeasts and their potential use in fish feed.

Selenium (Se) is a vital trace element, essential for growth and other biological functions in fish. Its significance lies in its role as a fundamental component of selenoproteins, which are crucial for optimal functioning of the organism. The inclusion of Se in the diets of farmed animals, including fish, has proved invaluable in mitigating the challenges arising from elemental deficiencies experienced in captivity conditions due to limitations in the content of fishmeal. Supplementing diets with Se enhances physiological responses, particularly mitigates the effects of the continuous presence of environmental stress factors. Organic Se has been shown to have higher absorption rates and a greater impact on bioavailability and overall health than inorganic forms. A characteristic feature of yeasts is their rapid proliferation and growth, marked by efficient mineral assimilation. Most of the selenized yeasts currently available in the market, and used predominantly in animal production and aquaculture, are based on Saccharomyces cerevisiae, which contains selenomethionine (Se-Met). The object of this review is to highlight the importance of selenized yeasts. In addition, it presents metabolic and productive aspects of other yeast genera that are important potential sources of organic selenium. Some yeast strains discussed produce metabolites of interest such as lipids, pigments, and amino acids, which could have applications in aquaculture and further enrich their usefulness.

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.

Saturnispora sinensis sp. nov., a new ascomycetous yeast species from soil and rotten wood.

A yeast strain (CGMCC 2.6937T) belonging to the ascomycetous yeast genus Saturnispora was recently isolated from soil collected in Xinghuacun, Shanxi Province, PR China. The strain produces one or two ellipsoid or spherical ascospores in asci formed by the conjugation between a cell and its bud. Phylogenetic analyses of the internal transcribed spacer (ITS) region and the D1/D2 domain of the large subunit rRNA gene suggest that this strain is conspecific with strains NYNU 14639 isolated from rotten wood collected in Funiu Mountain, Henan province and ES13S05 from soil collected in Nantou County, Taiwan. The CGMCC 2.6937T group is most closely related to Saturnispora dispora and Saturnispora zaruensis. However, strain CGMCC 2.6937T differs from S. dispora by 17 (3.2 %, 13 substitutions and four gaps) and 77 (18.8 %, 52 substitutions and 25 gaps) mismatches, and from S. zaruensis by 15 (2.9 %, 12 substitutions and three gaps) and 64 (15.6 %, 44 substitutions and 20 gaps) mismatches, in the D1/D2 domain and ITS region, respectively. The results suggest that the CGMCC 2.6937T group represents an undescribed species in the genus Saturnispora, for which the name Saturnispora sinensis sp. nov. is proposed. The holotype strain is CGMCC 2.6937T.

High Levels of Fungal and Aflatoxin Contamination of the Production Stages of the Local Brew (Ajono) consumed in Uganda

Local brew commonly known as Ajono is a widely consumed alcoholic beverage in Uganda. Handling practices along the production stages of the local brews may create a conducive environment for fungal colonization. This study aimed to assess fungal and aflatoxin contamination along the different production stages of Ajono from Soroti District in Eastern Uganda. A total of 180 samples were collected from the different stages along Ajono production. An interview guide was used to assess the processing practices while fungal contamination was assessed using standard microbiological methods. The study found that there are three main stages during Ajono production, namely; millet grain, fermented paste, and the liquid (Ajono) stages. During the paste fermentation stage, brewers used plastic drums (50%), pits (47%) or pots (3%) as fermentation vessels. Samples from plastic drum fermentation vessels had higher levels of fungal contamination than those from the pits and pots. Furthermore, several moulds genera including Aspergillus spp., Fusarium spp., Alternaria spp., Rhizopus spp., Penicillium spp., Cladosporium spp., and Acremonium spp. were identified along the production stages, with Aspergillus spp. as the most prevalent moulds at all stages of Ajono production. Two yeast genera; Saccharomyces spp. and Candida spp. were also isolated. Total Aflatoxin B and G group was detected along the production stages of Ajono with the highest prevalence (78.6%) seen in the liquid Ajono from pit fermenters and 68.8% in drum fermenters. Overall, all three stages of Ajono production; millet grain, fermented paste, and the liquid Ajono stages were highly contaminated with aflatoxigenic fungi which may cause adverse health effects under continued and sustained consumption of the brew

Isolation, characterization, and screening of yeast biodiversity for multi- hydrolytic enzymes

The current investigation was conducted with the objective of identifying yeasts that possess the ability to secrete a range of hydrolytic enzymes. Yeast isolates were collected from various samples, and the morphological characteristics of both the colony and yeast cells were examined. The capacity for enzyme production was assessed in multiple isolates by inoculating them in different media and quantifying their activities in terms of pectinase, amylase, urease, lipase, β-galactosidase, and protease. Out of a total of 42 yeast isolates, 30 displayed enzymatic activity. It is plausible that the yeast isolates obtained in this study hold potential for the production of industrial enzymes. Molecular identification techniques were employed to identify two isolates that exhibited multi-enzyme production and the highest enzyme activities. It was determined that these isolates belonged to two genera of yeasts, namely Pichia and Hanseniaspora. Specifically, isolate Y 16 was identified as Pichia kudriavizvii OL621856, while isolate Y 26 was identified as Hanseniaspora guillermondii OL621857 strains.

Blastobotrys nigripullensis, a new yeast species isolated from a fungal outbreak on an ancient Roman shipwreck in the Netherlands.

A new species of the yeast genus Blastobotrys was discovered on ancient ship timbers in the Netherlands. The species had developed on the wood of a river barge dating to the Roman period. The growth occurred after the preservative polyethylene glycol (PEG 4000) was washed out of some of the timbers due to an undetected leak in the storage unit. Mycological analysis of various timber samples revealed the presence of Microascus melanosporus (predominant), Microascus paisii, a member of the Acremonium chrysogenum-clade, and a new Blastrobotrys species. The new species produced sporothrix-like conidiophores with clavate blastoconidia (3-7 × 1-3.5μm) and was found to be osmotolerant, capable of growth on low water activity media like malt yeast 50% glucose agar (MY50G). In this article we formally describe and introduce Blastrobotrys nigripullensis (CBS 17879T) based on its morphology, physiology and phylogenetic placement.

Quantitative composition and taxonomic structure of endophytes of agricultural crops

Various vegetative organs of the studied crops yielded 320 isolates of cultivated forms of micromycetes, with a predominance of filamentous fungi (249 strains). The level of colonization by fungi varied widely, ranging from 6 to 40%. This indicator was lower for yeast, ranging from 2 to 12%. The isolation ratio of fungal strains ranged from 0.08 to 0.54, while yeast strains ranged from 0.02 to 0.2. The taxonomic composition of endophytic micromycetes complexes in the studied agrocultures included 7 genera of filamentous fungi (Penicillium, Aspergillus, Fusarium, Trichoderma, Beauveria, Metarhizium, and Cladosporium) and 4 genera of yeasts and yeast-like fungi (Rhodotorula, Aureobasidium, Metschnikowia, and Cryptococcus). The greatest taxonomic diversity was observed in soybean and sweet clover. Barley and sainfoin also exhibited considerable diversity. The quantitative composition and taxonomic structure of endophytes are largely influenced by species, physiological state and stage of development of the host plant, type of plant tissues and organs, and environmental conditions.

Understanding the molecular mechanisms of human diseases: the benefits of fission yeasts.

The role of model organisms such as yeasts in life science research is crucial. Although the baker's yeast (Saccharomyces cerevisiae) is the most popular model among yeasts, the contribution of the fission yeasts (Schizosaccharomyces) to life science is also indisputable. Since both types of yeasts share several thousands of common orthologous genes with humans, they provide a simple research platform to investigate many fundamental molecular mechanisms and functions, thereby contributing to the understanding of the background of human diseases. In this review, we would like to highlight the many advantages of fission yeasts over budding yeasts. The usefulness of fission yeasts in virus research is shown as an example, presenting the most important research results related to the Human Immunodeficiency Virus Type 1 (HIV-1) Vpr protein. Besides, the potential role of fission yeasts in the study of prion biology is also discussed. Furthermore, we are keen to promote the uprising model yeast Schizosaccharomyces japonicus, which is a dimorphic species in the fission yeast genus. We propose the hyphal growth of S. japonicus as an unusual opportunity as a model to study the invadopodia of human cancer cells since the two seemingly different cell types can be compared along fundamental features. Here we also collect the latest laboratory protocols and bioinformatics tools for the fission yeasts to highlight the many possibilities available to the research community. In addition, we present several limiting factors that everyone should be aware of when working with yeast models.

Comparison of microbial diversity and metabolites on household and commercial doenjang

In this study, the microbial diversity, free amino acid (FAA), and biological activities of household doenjang (HDJ) from four different regions and commercial doenjang (CDJ) four manufacturers were analyzed. And volatile flavor compound (VFC) and isoflavone profiles were analyzed using gas chromatograph-mass spectrometer (GC-MS) and high performance liquid chromatography (HPLC), respectively. The major bacterial genus in 1HDJ and 2HDJ was Bacillus (97.5%), while in 3HDJ and 4HDJ, it was Enterobacter (47.5%) and Pseudomonas (80%), respectively. Tetragenococcus was the main bacterial genus of CDJ. The Zygosaccharomyces genus among yeast was comparatively high in all samples. In all samples, glutamic acid predominated among the FAAs, and the 3-methyl butanal, benzeneacetaldehyde, and diallyl disulphide were major VFCs. CDJ contained higher levels of isoflavone-glycoside and total phenolics. Except for 3HDJ and 4CDJ, the isoflavone-aglycone and total flavonoid contents were higher in HDJ. The correlation between bacterial genus and metabolited of doenjang showed that Tetragenococcus was closely related to glutamic acid, Bacillus was related to aglycones and ammonia, and Pseudomonas was highly related to isovaleric acid. While, correlation between yeast genus and metabolited of doenjang confirmed that Candida, Hanseniaspora, and Saccharomyces were related with furfural, benzeneacetaldehyde, and 3-methyl butanal, respectively. The results of this study can be utilized as basic data for the industrialization and development of doenjang.

Integrating shotgun metagenomics and metabolomics to elucidate the dynamics of microbial communities and metabolites in fine flavor cocoa fermentation in Hainan

The aim of this study was to investigate the dynamic profile of microorganisms and metabolites in Hainan Trinitario cocoa during a six-day spontaneous box fermentation process. Shotgun metagenomic and metabolomic approaches were employed for this investigation. The potential metabolic functions of microorganisms in cocoa fermentation were revealed through a joint analysis of microbes, functional genes, and metabolites. During the anaerobic fermentation phase, Hanseniaspora emerged as the most prevalent yeast genus, implicated in pectin decomposition and potentially involved in glycolysis and starch and sucrose metabolism. Tatumella, possessing potential for pyruvate kinase, and Fructobacillus with a preference for fructose, constituted the primary bacteria during the pre-turning fermentation stage. Upon the introduction of oxygen into the fermentation mass, acetic acid bacteria ascended to dominant within the microflora. The exponential proliferation of Acetobacter resulted in a decline in taxonomic richness and abundance. Moreover, the identification of novel species within the Komagataeibacter genus suggests that Hainan cocoa may serve as a valuable reservoir for the discovery of unique cocoa fermentation bacteria. The KEGG annotation of metabolites and enzymes also highlighted the significant involvement of phenylalanine metabolism in cocoa fermentation. This research will offer a new perspective for the selection of starter strains and the formulation of mixed starter cultures.

Genomic analysis of the marine yeast Rhodotorula sphaerocarpa ETNP2018 reveals adaptation to the open ocean

BackgroundDespite a rising interest in the diversity and ecology of fungi in marine environments, there are few published genomes of fungi isolated from the ocean. The basidiomycetous yeast (unicellular fungus) genus Rhodotorula are prevalent and abundant in the open ocean, and they have been isolated from a wide range of other environments. Many of these environments are nutrient poor, such as the Antarctica and the Atacama deserts, raising the question as to how Rhodotorula yeasts may have adapted their metabolic strategies to optimize survival under low nutrient conditions. In order to understand their adaptive strategies in the ocean, the genome of R. sphaerocarpa ETNP2018 was compared to that of fourteen representative Rhodotorula yeasts, isolated from a variety of environments.ResultsRhodotorula sphaerocarpa ETNP2018, a strain isolated from the oligotrophic part of the eastern tropical North Pacific (ETNP) oxygen minimum zone (OMZ), hosts the smallest of the fifteen genomes and yet the number of protein-coding genes it possesses is on par with the other strains. Its genome exhibits a distinct reduction in genes dedicated to Major Facilitator Superfamily transporters as well as biosynthetic enzymes. However, its core metabolic pathways are fully conserved. Our research indicates that the selective pressures of the ETNP OMZ favor a streamlined genome with reduced overall biosynthetic potential balanced by a stable set of core metabolisms and an expansion of mechanisms for nutrient acquisition.ConclusionsIn summary, this study offers insights into the adaptation of fungi to the oligotrophic ocean and provides valuable information for understanding the ecological roles of fungi in the ocean.