TY - JOUR A1 - Erdmann, Eileen A. A1 - Brandhorst, Antonia K. M. A1 - Gorbushina, Anna A1 - Schumacher, Julia T1 - The Tet‑on system for controllable gene expression in the rock‑inhabiting black fungus Knufia petricola N2 - Knufia petricola is a black fungus that colonizes sun-exposed surfaces as extreme and oligotrophic environments. As ecologically important heterotrophs and biofilm-formers on human-made surfaces, black fungi form one of the most resistant groups of biodeteriorating organisms. Due to its moderate growth rate in axenic culture and available protocols for its transformation and CRISPR/Cas9-mediated genome editing, K. petricola is used for studying the morpho-physiological adaptations shared by extremophilic and extremotolerant black fungi. In this study, the bacteria-derived tetracycline (TET)-dependent promoter (Tet-on) system was implemented to enable controllable gene expression in K. petricola. The functionality i.e., the dose-dependent inducibility of TET-regulated constructs was investigated by using GFP fluorescence, pigment synthesis(melanin and carotenoids) and restored uracil prototrophy as reporters. The newly generated cloning vectors containing the Tet-on construct, and the validated sites in the K. petricola genome for color-selectable or neutral insertion of expression constructs complete the reverse genetics toolbox. One or multiple genes can be expressed on demand from different genomic loci or from a single construct by using 2A self-cleaving peptides, e.g., for localizing proteins and protein complexes in the K. petricola cell or for using K. petricola as host for the expression of heterologous genes. KW - Microcolonial fungi KW - Inducible promoter KW - Bimolecular fluorescence complementation KW - 2A peptide KW - CRISPR/ Cas9-mediated genome editing PY - 2024 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-607672 DO - https://doi.org/10.1007/s00792-024-01354-2 VL - 28 IS - 38 SP - 1 EP - 13 PB - Springer Nature AN - OPUS4-60767 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Schumacher, Julia T1 - DHN melanin synthesis in the rock inhabitant Knufia petricola N2 - DHN (1,8-dihydroxynaphthalene) melanin is produced by Ascomycetes via slightly differing synthetic routes. Polyketide synthases release YWA1, AT4HN or T4HN. YWA1 and AT4HN are deacetylated by ‘yellowish-green’ hydrolases, and T4HN is converted by a core set of enzymes to DHN. Final polymerization steps are accomplished by multicopper oxidases. The melanogenic genes are tightly, partially or not clustered in the genomes, and are often regulated in a spatial and/or temporal fashion. By contrast, microcolonial fungi/black yeasts – a polyphyletic group of Ascomycetes dwelling in hostile habitats such as bare rock surfaces – feature constitutive DHN melanogenesis. Here, we report on the DHN melanogenic genes of Knufia petricola (Eurotiomycetes/Chaetothyriales). T2 - 16th European Conference on Fungal Genetics CY - Innsbruck, Austria DA - 05.03.2023 KW - DHN melanin KW - Fungus KW - Biosynthesis PY - 2023 AN - OPUS4-57143 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Schumacher, Julia A1 - Gorbushina, Anna T1 - Light sensing in plant- and rock-associated black fungi N2 - Fungi that share light-flooded habitats with phototrophs may profit from their excess photosynthetic products. But to cope with sunlight-associated stresses [e.g. high temperatures, UV radiation with associated DNA damage, accumulation of reactive oxygen species (ROS), desiccation and osmotic stresses] it is important for fungi to accurately sense and respond to changes in light. To test the hypothesis that light is an environmental cue that Ascomycota use to coordinate growth, stress responses as well as to establish pathogenic or symbiotic relationships, the photoreceptor (PR) distribution in species from different ecological niches was analysed. The genomes of black [dihydroxynaphthalene (DHN) melanin-containing] fungi from phyllosphere and exposed solid surfaces contain multiple photoreceptors (PRs). The plant pathogen Botrytis cinerea (Leotiomycetes) has a highly sophisticated photosensory and signalling system that helps to avoid light and to locate susceptible hosts. Rock-inhabiting Dothideomycetes and Eurotiomycetes including Knufia petricola possess equal numbers ofPRs along with the same set of protective pigments. This similarity between black fungi from plant and rock surfaces suggests that photoperception and -regulation are important for fungi that receive nutrients through cooperation with phototrophs. Genetic tools for manipulating K. petricola exist and will be used to test this idea. KW - Botrytis cinerea KW - DHN melanin KW - Knufia petricola KW - Phyllosphere KW - Rock biofilm PY - 2020 DO - https://doi.org/10.1016/j.funbio.2020.01.004 VL - 124 IS - 5 SP - 407 EP - 417 AN - OPUS4-50786 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Schumacher, Julia T1 - Genetic manipulation of the microcolonial black fungus Knufia petricola N2 - Microcolonial black fungi, a polyphyletic group of ascomycetes, exhibit constitutive melanin formation, yeast-like growth and high stress tolerances. They dominate – often together with bacteria and algae in sub-aerial biofilms – a range of hostile environments including natural and man-made ones, from salterns to dishwashers, roofs and solar panels. Because of lacking genetic tools and the slow growth of most isolates, the genetic bases for these specific properties are largely unknown. The rock-inhabiting fungus Knufia petricola (Eurotiomycetes, Chaetothyriales) exhibits all characteristics of microcolonial black fungi and was selected as recipient for genetic engineering to study gene functions and genetic interactions. Different variants of green and red fluorescent proteins were successfully expressed indicating that fluorescence microscopy using genetically encoded fluorescent proteins and fluorescent dyes enables various cell biology approaches. Furthermore, genes of biosynthetic pathways (DHN melanin, carotenoids, uracil, adenine) were successfully mutated by applying traditional gene replacement and plasmid-based or ribonucleoprotein (RNP)-based CRISPR/Cas9 or silenced by RNA interference (RNAi). The availability of this advanced and efficient genetic toolbox and the annotated genome sequence of strain A95 makes K. petricola an excellent model for exploring the secrets of microcolonial black fungi. T2 - Departmental colloquium of the Tuscia University CY - Viterbo, Italy DA - 14.02.2020 KW - black fungus KW - genetics KW - Crispr/Cas9 PY - 2020 AN - OPUS4-50592 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Erdmann, Eileen T1 - Tools for Knufia petricola: new techniques for CRISPR/Cas9-based genome editing N2 - Black microcolonial fungi represent a group of ascomycetes with similar adaptations for existing in natural and anthropogenically created extreme habitats. They exhibit slow yeast-like or meristematic growth, do not form specialized reproduction structures and accumulate the black pigment 1,8-dihydroxynaphthalene (DHN) in the multilayered cell walls. We chose the rock inhabitant Knufia petricola of the Chaetothyriales as a representative for developing methods for genetic manipulation, simulation of mineral weathering and study of symbiotic interactions. Here, we report on the expansion of the genetic toolkit by more efficient multiplex CRISPR/Cas9 using a plasmid-based system for expression of Cas9 and multiple sgRNAs and three additional resistance selection markers. The targeted integration of expression constructs by replacement of essential genes for pigment synthesis allows for an additional color screening of the transformants. The black-pink screening due to the elimination of pks1 (melanin) was applied for promoter studies using GFP fluorescence as reporter, while the black-white screening due to the concurrent elimination of pks1 (melanin) and phs1 (carotenoids) was used to identify transformants that contain the two expression constructs for co-localization or bimolecular fluorescence complementation (BiFC) studies. In addition, two intergenic regions (igr1, igr2) were identified in which expression constructs can be inserted without causing obvious phenotypes. Plasmids of the pNXR-XXX series (Schumacher, 2012) and new compatible entry plasmids were used for fast and easy generation of expression constructs and are suitable for use in other fungal systems as well. T2 - 31st Fungal Genetics Conference CY - USA, CA, Pacific Grove DA - 15.03.2022 KW - Microcolonial fungi KW - Genetic engineering KW - Fluorescent proteins PY - 2022 AN - OPUS4-54586 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Schumacher, Julia T1 - Looking through the eyes of fungi: from photoperception to photoresponses and beyond N2 - Sunlight is an almost unavoidable environmental cue and plays a fundamental role in the biology of pro- and eukaryotic organisms. To cope with sunlight-associated stresses e.g., high temperatures, UV radiation, accumulation of reactive oxygen species, desiccation, and osmotic stress, it is important for organisms to accurately sense and respond to changes in light. The benefits of light are obvious for green organisms such as cyanobacteria, algae and plants which use light as an energy source (photosynthesis). Fungi that can share light-flooded habitats with phototrophs may profit from their excess photosynthetic products. Examples are the plant pathogen Botrytis cinerea, the gray mold fungus, and the rock inhabitant Knufia petricola, a microcolonial black fungus which forms multispecies biofilms with bacteria and algae. T2 - 20th Symposium of the Research Training Group on Bioactive Peptides – The colorful tree of life CY - Berlin, Germany DA - 23.01.2024 KW - Black fungi KW - Melanin KW - Stress tolerance PY - 2024 AN - OPUS4-59543 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Schumacher, Julia T1 - How does light affect rock-inhabiting fungi? N2 - Sunlight is an almost unavoidable environmental cue and plays a fundamental role in the biology of pro- and eukaryotic organisms. To cope with sunlight-associated stresses e.g., high temperatures, UV radiation with associated DNA damage, accumulation of reactive oxygen species (ROS), desiccation and osmotic stresses, it is important for organisms to accurately sense and respond to changes in light. The benefits of light are obvious for green organisms such as cyanobacteria, algae and plants which use light as an energy source (photosynthesis). Less apparent are other light-dependent processes such as light-driven DNA repair by photolyases (photoreactivation) or ion pumping by microbial opsins. Fungi that can share light-flooded habitats with phototrophs may profit from their excess photosynthetic products. Rock-inhabiting Dothideomycetes and Eurotiomycetes including Knufia petricola possess many proteins for absorbing UV/blue, green, red and far-red light, produce the black 1,8 dihydroxynaphthalene (DHN) melanin and orange-red carotenoids, and may live in multispecies biofilms. Here, we are addressing the question to which extent constitutive pigment formation (melanin and carotenoids) and responses mediated by the stress-activated mitogen-activated protein (MAP) kinase contribute to the observed light (UV-B) tolerance of K. petricola. T2 - 32nd Fungal Genetics Conference CY - Pacific Grove, CA, USA DA - 12.03.2024 KW - Knufia petricola KW - Black fungi KW - Light-induced stress PY - 2024 AN - OPUS4-59732 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - von Werder, Julia T1 - Gebäudebegrünung mit Biofilmen: Herausforderungen und Chancen N2 - Der Vortrag stellt die Ergebnisse der Forschungsarbeiten zur Biorezeptivität von Betonfassaden sowie der gezielten Applikation von Algen dominierten Biofilmen auf Betonfassaden vor. Insbesondere werden die Anforderungen an eine repräsentative Prüfmethode erläutert. T2 - BuGG-Tag der Forschung und Lehre Gebäudegrün 2024 CY - Leipzig, Germany DA - 26.09.2024 KW - Begrünung KW - Biorezeptivität KW - Beton KW - Biofilm PY - 2024 AN - OPUS4-62221 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - von Werder, Julia T1 - Biorezeptivität und Optimierung von Lehmbaustoffen - Forschung an der BAM N2 - Der Vortrag fasst die Forschungsaktivitäten der BAM in den Themengebieten Biorezeptivität von Beton und Optimierung von Lehmbaustoffen zusammen. Er diente als Kurzpräsentation für eine anschließende Podiumsdiskussion. T2 - Transformationsdialog "Material als Motor" CY - Berlin, Germany DA - 10.10.2024 KW - Biorezeptivität KW - Beton KW - Lehmbaustoffe PY - 2024 AN - OPUS4-62220 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - von Werder, Julia T1 - Living Concrete Walls: Engineering Bioreceptivity and Biofilms N2 - Building envelopes are a natural habitat of subaerial biofilms and can be more or less prone to be colonized (i.e. to be bioreceptive). Focusing on the added value of biofilms on manmade substrates represents new aesthetic frontiers and reduces the use of biocides. Moreover, the metabolic processes of photosynthetic biofilms can positively influence human health and life quality in densely populated cities by converting or absorbing pollutants. In the presented research the bioreceptivity of concrete claddings for building facades is engineered to sustain either natural or artificial establishment of microalgae-dominated biofilms. To be able to differentiate between the intrinsic material properties and the climatic boundary conditions, the experimental design in the first step comprised different analyses with model mono- and multi-species biofilms in sterile conditions and a high control of the environmental parameters. Growth and vitality of the algal component of the biofilms has been assessed with Pulse-amplitude modulation (PAM) fluorometry. T2 - 78th RILEM Annual Week & RILEM International Conference on Sustainable Materials & Structures: Meeting the major challenges of the 21st century - SMS 2024 CY - Toulouse, France DA - 25.08.2024 KW - Bioreceptivity KW - Biofilm KW - Weathering KW - Concrete KW - PAM fluorometry KW - Carbonation PY - 2024 AN - OPUS4-62224 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Geburtig, Anja A1 - Gorbushina, Anna A1 - Plarre, Rüdiger A1 - Stephan, Ina T1 - Umweltsimulation an der BAM – Grundlegende Ansätze mit Beispielen aus der natürlichen Umwelt N2 - Drei grundlegend verschiedene Ansätze für Umweltsimulation werden an Beispielen illustriert: (i) Ganzheitlicher Ansatz - Nachstellen von Umweltmilieus im Labor Ziel ist hier das Nachstellen von (kombinierten) Umweltbedingungen im Labor; die Umweltparameter werden mit all ihren Wechselwirkungen aufgebracht. Hauptnutzen ist eine gegenüber der natürlichen Beanspruchung erhöhte Reproduzierbarkeit der Umweltbedingungen. Hat man sein Laborsetup entwickelt, ist es auf verschiedene Materialien anwendbar. Unter solchen Laborbedingungen ermittelte Lebensdauern sind dabei nicht auf die typischerweise sehr variablen Real-Umweltbedingungen übertragbar. (ii) Parametrisierter Ansatz - Ermittlung einzelner Materialempfindlichkeiten Hierbei werden im Labor die Wirkungen separater Umweltparameter auf Materialien nachgestellt. Für eine solche Separation der Einflussfaktoren ist insbesondere die Aufschlüsselung möglicher Wechselwirkungen der Umwelt-parameter (z.B. Mikroklima an bestrahlten Oberflächen) erforderlich. Einzelne (meist Alterungs-) Empfindlichkeiten können qualitativ nachgewiesen werden oder sogar – als Beanspruchungs-Wirkungs-Funktionen – quantifiziert werden, was einen wesentlichen Schritt in Richtung der Digitalisierung der Material¬prüfung darstellt. Insbesondere ist dann auch eine Lebensdauer-vorhersage für vorgegebene Zeitreihen der Beanspruchungs¬parameter umsetzbar. (iii) Rückwirkungen auf die Umwelt Umweltbeanspruchungen können zur Freisetzung von Schadstoffen in die Umwelt führen. Durch die Nachstellung kritischer, aber realitätsnaher Einsatzszenarien kann die Menge an freigesetzten Substanzen abgeschätzt werden. Egal, welcher Ansatz verfolgt wird – ein Vergleich mit der oder einer Real-beanspruchung ist unerlässlich, ebenso wie die Messdatenaufzeichnung (data logging) aller potenziell relevanten Beanspruchungsparameter während dieser Realbeanspruchung. Obwohl die naturnahe Umwelt – sowohl in der BAM als auch bei der GUS – gegenüber der technischen Umwelt eher untergeordnet auftritt, werden zur Illustration Beispiele aus der naturnahen Umwelt verwendet. T2 - 50. Jahrestagung der GUS CY - Online meeting DA - 23.03.2022 KW - Umweltsimulation PY - 2022 SN - 978-3-9818507-7-2 SP - 79 EP - 89 AN - OPUS4-55015 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Schumacher, Julia T1 - Unlocking black fungi: from genomes to material conservation and biotechnological innovation N2 - Black fungi are a polyphyletic group of melanized ascomycetes adapted to extreme environments such as deserts, rocks, and human-made surfaces. Their slow compact growth, and thick melanized cell walls confer exceptional stress tolerance but have long hindered molecular studies and genetic engineering. Consequently, the biology and biotechnological potential of these organisms remained largely unexplored. To overcome these limitations, we selected the rock-inhabiting black fungus Knufia petricola as a model. Its genome sequence (12 contigs, ~10,000 genes) enabled the development of a versatile genetic toolbox based on CRISPR/Cas9-mediated editing, achieving up to 100% homologous recombination and supporting multiplex editing of at least six genomic regions. Color-based selection systems targeting pigment genes enable rapid identification of strains with correctly integrated expression cassettes, including simultaneous insertion of optimized genes coding for blue, green, and red fluorescent proteins for co-localization and protein interaction studies. These tools enable functional analyses of traits central to extremotolerance, such as the role of melanin in stress protection, biofilm formation, and material interactions. Furthermore, K. petricola has been established as a eukaryotic expression platform: heterologous genes from bacteria, fungi, and plants can be expressed under constitutive or inducible promoters, including the Tet-on system for tunable gene regulation. Pigment-free strains provide access to metabolic precursors, enabling high-level synthesis of alternative secondary metabolites. Importantly, the optimized transformation protocols were successfully transferred to the Antarctic black fungus Cryomyces antarcticus, a cryptoendolithic extremophile and astrobiology model, demonstrating that even the most stress-tolerant fungi can be genetically engineered. Together, the genome sequence and advanced genetic engineering strategies have transformed K. petricola from a challenging extremotolerant organism into a tractable model for studying stress adaptation, material interactions and a promising host for biotechnology and synthetic biology approaches. These achievements, combined with emerging black fungal genomes, inform sustainable material protection strategies to mitigate colonization and biodeterioration of exposed surfaces, linking fundamental research with applied solutions for material conservation and industrial biotechnology. T2 - Annual Conference of the Association for General and Applied Microbiology (VAAM) 2026 CY - Berlin, Germany DA - 22.03.2026 KW - Functional genetics KW - Material colonizer KW - Pigments PY - 2026 AN - OPUS4-65752 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Schumacher, Julia T1 - Biodiversity on Materials: Black Fungi Colonizing Solar Panels N2 - Sun-exposed surfaces are extreme environments characterized by intense UV radiation, temperature fluctuations, desiccation, and nutrient scarcity. These habitats are colonized by extremotolerant microorganisms that often form multispecies biofilms. Among them, black fungi (Ascomycota) stand out for their unique morphophysiological traits: slow growth, small compact colonies, reproduction by budding or meristematic growth, and continuous deposition of 1,8-dihydroxynaphthalene (DHN) melanin on thickened cell walls. This melanin is thought to provide protection against abiotic stress, for both the fungi and their microbial partners. Originally associated with natural substrates such as rocks in hot, cold, or saline deserts, black fungi have recently been detected on human-made surfaces, including solar panels, where they may reduce system efficiency. Despite their simple morphology, black fungi represent a vast and underestimated genetic diversity with representatives in Eurotiomycetes, Dothideomycetes, and Arthoniomycetes. They exhibit diverse lifestyles, including lichen symbioses, opportunistic pathogenicity, and saprobic growth. However, only a few genomes of black fungi have been sequenced to date. Initial analyses indicate haploid or diploid states, occasional genome duplications, and gene loss, reflecting adaptation to extreme conditions. For even fewer species, genetic engineering tools are available. To address this gap, we develop genetic tools for functional studies and compare genome sequences. The STRES Community Science Program, funded by the Joint Genome Institute (JGI), aims to sequence up to 600 black fungal genomes from diverse extreme environments (https://stresblackfungi.org/). Our contribution includes black fungi isolated from solar panels in Germany and the United States – among some several new species. Annotated genomes are now becoming available, enabling comparative analyses to discover novel genes for enzymes and secondary metabolites. These efforts also support strategies to mitigate undesired biofilm formation on man-made surfaces such as facades and solar panels. T2 - Annual Conference of the Association for General and Applied Microbiology (VAAM) 2026 CY - Berlin, Germany DA - 22.03.2026 KW - Biodiversity KW - Fungi KW - Melanin PY - 2026 AN - OPUS4-65750 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Erdmann, Eileen A. T1 - In-vivo Transposon Mutagenesis in the Black Fungus Knufia petricola N2 - Microcolonial black fungi, commonly found on sun-exposed natural and man-made surfaces worldwide, belong to different classes within the Ascomycota but convergently evolved similar morpho-physiological adaptations to colonize extreme low-competitive environments. Genetic studies of these organisms have long been hampered by slow growth, lack of sexual cycles and difficulties in transformation. To overcome these limitations, CRISPR/Cas9-based genome editing was implemented in the rock-inhabiting fungus Knufia petricola (Eurotiomycetes, Chaetothyriales). This enables efficient generation of deletion mutants and overexpression strains for functional analyses, and thus hypothesis-driven targeted mutagenesis. However, the unique ability of black fungi to colonize oligotrophic extreme environments remains poorly understood, and genes involved are unknown. To address this, a hypothesis-generating tool for functional assessment of new species- and/or trait-specific genes was implemented in K. petricola. Specifically, we adapted the two-component Activator/Dissociation (Ac/Ds) transposon system from maize for generating insertional mutants by in vivo mutagenesis. For controlling the transposition of a Ds transposon carrying a resistance cassette, the inducible and metabolism-independent Tet-on promoter system was combined with the Ac transposase (AcTPase) coding sequence fused to a functional nuclear localization signal. In total, six auxotrophic Ac/Ds starter strains were generated, each harboring the Ds transposon at different positions within ade2, ura3 or ppt1. Induction of TET::AcTPase with doxycycline followed by selection on ADE/URA/LYS-lacking media resulted in prototrophic revertants for most Ac/Ds strains. Sequencing of excision sites revealed characteristic footprints. Mapping of Ds re-insertion sites demonstrated transpositions both within the same chromosome and across different chromosomes, identifying 30 genes as non-essential. Current efforts include scaling up mutant generation, as the generation and sequencing of saturated mutant libraries combined with mutation mapping will enable the systematic identification of essential genes under diverse culture conditions. T2 - Annual Conference of the Association for General and Applied Microbiology (VAAM) 2026 CY - Berlin, Germany DA - 22.03.2026 KW - Genetics KW - Material colonizer KW - Melanin PY - 2026 AN - OPUS4-65749 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Schumacher, Julia T1 - Iron Acquisition in Black Fungi: Genomic Insights & Mitigation N2 - Iron is an essential micronutrient for all organisms, driving intense competition for its acquisition. This competition is particularly evident in parasitic interactions, where hosts actively restrict iron availability to inhibit the growth of fungal invaders (nutritional immunity). Saprobic fungi, on the other hand, acquire iron by digesting dead organic material and may protect their nutrient sources from competitors through efficient iron uptake, rapid growth, and the production of toxic secondary metabolites. Rock-inhabiting black fungi colonize – alone or within microbial communities (subaerial biofilms) – oligotrophic, exposed surfaces such as rocks, stone monuments, and photovoltaic panels, where competition from fast-growing saprobes is minimal. To understand how these fungi acquire iron, we combined comparative genomics with targeted gene deletions in the model species Knufia petricola. Genome analysis revealed a reduced repertoire of iron acquisition-related genes compared to those of pathogenic relatives: a single reductive iron assimilation (RIA) complex, one non-ribosomal peptide synthetase (NRPS) for siderophore biosynthesis, and absence of vacuolar iron transporters. Functional assays demonstrated that K. petricola primarily relies on RIA, mediated by FTR1–FET1, and secondarily on siderophore-mediated iron acquisition (SIA) via NPS1. Mutants lacking both systems were nearly non-viable under iron limitation, confirming that RIA and SIA are the only relevant uptake routes under laboratory conditions, that simulate the free-living lifestyle. Cross-feeding and chemotropism assays indicated secretion of an extracellular siderophore enabling growth toward the iron-containing mineral olivine. This siderophore, however, failed to mobilize iron from strong chelators such as BPS and EDTA, and its chemical nature remains unknown. Although melanin adsorbs and reduces iron, results on deletion mutants showed that melanin does not contribute to iron uptake or chelator resistance, functioning instead as a passive iron sink. Sensitivity assays revealed unusually low minimal inhibitory concentrations (MICs) for these chelators in K. petricola and other rock-inhabiting fungi, suggesting limited iron acquisition and storage capacity. These findings highlight the vulnerability of rock-inhabiting fungi to iron depletion and suggest that strong iron chelators could serve as an effective strategy to inhibit fungal colonization of human-made surfaces. T2 - Annual Conference of the Association for General and Applied Microbiology (VAAM) 2026 CY - Berlin, Germany DA - 22.03.2026 KW - Material colonization KW - Knufia petricola KW - Iron chelation PY - 2026 AN - OPUS4-65751 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Cockx, Bastiaan J.R. T1 - From data to model, linking Knufia petricola traits to emergent biofilm properties using individual-based experiments and modelling N2 - Black fungi, a diverse group of ascomycetes, well known for their ability to thrive in extreme environments, are found to colonize and grow on subaerial surfaces where few other microbes survive. This includes bare rock as well as marble monuments and solar panels. Black fungi can deteriorate hard substrates which is of particular concern for the preservation of cultural heritage, while their ability to colonize solar panels can cause a reduction in green energy yield. We have been developing computational modelling tools to gain predictive insight into their growth and proliferation. In this work we focus on the black fungus Knufia petricola, a fungus that possesses many of the characteristic features of black fungi generally and for which genetic engineering tools have been developed. Detailed observations and systematic characterization of the organism are fundamental to developing a predictive model. We combined the lessons from individual-based and biofilm characterization studies of K. petricola by Dehkohneh et al. (Manuscripts in preparation) with the predictive potential of Individual-based Modelling (IbM). In these systematic characterization studies K. petricola was grown and characterized on agar and on a glass substrate. K. petricola was grown under a variety of conditions; different carbon and nitrogen sources, different degrees of nutrient limitation, and C:N ratios. We"ve thus gained insight on how these conditions affect the growth characteristics and morphological development of K. petricola, including how nutrient limitation can limit branch development and shift generation times, and how the C:N ratio affects substrate penetration. We employed this knowledge to develop a new K. petricola IbM.We used the IbM framework iDynoMiCS 2.0 (Cockx et al. 2024) to formulate our model. The model captures both morphological and kinetic aspects of K. petricola. By formulating characteristics of individual cells and the interactions with their neighbors and environment mathematically we can simulate emergent properties, such as the architecture and expansion of K. petricola micro- colonies, which gives us the unique ability to link microbial traits with biofilm characteristics. The model gives us insight on how environmental parameters can be manipulated to steer the development of K. petricola biofilms, it can thus help forecast K. petricola biofilm proliferation and can be used to inform new bio-colonization mitigation strategies. T2 - Annual Conference of the Association for General and Applied Microbiology (VAAM) 2026 CY - Berlin, Germany DA - 22.03.2026 KW - Rock-inhabiting fungi KW - Extreme environments KW - Fungal growth PY - 2026 AN - OPUS4-65755 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -