Adaptative cellular and metabolomic responses to salinity of black yeasts isolated from deep-sea sediments of the Gulf of Mexico

Adaptative cellular and metabolomic responses to salinity of black yeasts isolated from deep-sea sediments of the Gulf of Mexico | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Article Adaptative cellular and metabolomic responses to salinity of black yeasts isolated from deep-sea sediments of the Gulf of Mexico Meritxell Riquelme, Maria Dolores Camacho-López, Mario Alberto Figueroa Saldivar, and 1 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-7032826/v1 This work is licensed under a CC BY 4.0 License Status: Published Journal Publication published 10 Feb, 2026 Read the published version in Communications Biology → Version 1 posted You are reading this latest preprint version Abstract Black yeasts are extremotolerant fungi that thrive in high-salinity environments, supported by melanin production and morphological and molecular adaptations. In this study, we isolated three black yeast species, Salinomyces thailandicus, Neophaeotheca triangularis, and Neophaeotheca salicorniae, from deep sediments of the Gulf of Mexico. We examined their morphology, cell division, growth, and metabolomic profiles under varying salinities (3.5% sea salt; 10% and 20% NaCl), and in the presence of the melanin inhibitor phthalide (PHT). Species-specific responses emerged: S. thailandicus shifted from filamentous to yeast-like growth with increasing salinity; N. triangularis showed the reverse; N. salicorniae remained dimorphic but exhibited reduced cell division at higher salinities. S. thailandicus divided by budding, while both Neophaeotheca species employed endoconidiogenesis. Phthalide exposure suppressed hyphal development in all three. Pores observed on Neophaeotheca cell surfaces, may mediate extracellular melanin granules transport. Untargeted metabolomics revealed salinity-dependent shifts in metabolite profiles, with higher metabolite abundance under PHT treatment. Fatty acids represented the most prominent metabolic pathway and may contribute to melanin biosynthesis. Additional metabolites included amino acids, peptides, alkaloids, terpenoids, and polyketides, some with potential biotechnological relevance. These findings advance our understanding of black yeasts adaptation to osmotic stress and highlight their ecological significance in marine environments. Biological sciences/Microbiology/Fungi/Fungal biology Biological sciences/Microbiology/Cellular microbiology extreme halotolerance yeast-like growth endoconidiogenesis melanin metabolome Full Text Additional Declarations There is NO Competing Interest. Supplementary Files SupplementaryinformationMetabolomics.docx Details on extract preparation for metabolomic analysis and metabolomics data processing LinksFBMNMoldiscoveryDereplicator.docx Links with parameters for feature-based molecular networking and spectral matching, Moldiscovery and Dereplicator using all data sets TableS1.ListoffeaturesclassificationassessedbyCANOPUS.xlsx Table S1. List of features classification assessed by CANOPUS FigureS1.ColoniesPHTgrowht.tif Effect of DHN-melanin inhibitor phthalide (PHT) on growth and colony morphology of S. thailandicus, N. triangularis, and N. salicorniae under different salt concentrations. VideoS1Sthailandicus.mov Time lapse video featuring cell division of S. thailandicus under different salt concentrations. VideoS2Ntriangularis.mov Time lapse video featuring cell division of N. triangularis under different salt concentrations. VideoS3Nsalicorniae.mov Time lapse video featuring cell division of N. salicorniae under different salt concentrations. Cite Share Download PDF Status: Published Journal Publication published 10 Feb, 2026 Read the published version in Communications Biology → Version 1 posted You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. We do this by developing innovative software and high quality services for the global research community. Our growing team is made up of researchers and industry professionals working together to solve the most critical problems facing scientific publishing. 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Untargeted metabolomics revealed salinity-dependent shifts in metabolite profiles, with higher metabolite abundance under PHT treatment. Fatty acids represented the most prominent metabolic pathway and may contribute to melanin biosynthesis. Additional metabolites included amino acids, peptides, alkaloids, terpenoids, and polyketides, some with potential biotechnological relevance. 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