In plants, the indolic amino acid tryptophan (Trp) serves as the precursor for the synthesis of a plethora of indolic secondary metabolites with allelopathic activity against microbes or toxicity against herbivores. In the cruciferous model plant Aradidopsis, indolic glucosinolates, the major phytoalexin camalexin, carbonyl nitriles and indole carboxylic acids are abundant products of the branched biosynthetic pathway that originates from the Trp oxidation product indole-acetaldoxime (IAOx). To date, it has not been intensely investigated, (i) how the Arabidopsis indolic metabolic network responds to fungal infection and (ii) which indolic metabolites play a role for compatibility upon fungal attack. To provide a systematic case study, we have employed a combination of single, double, triple and quadruple Arabidopsis mutants lacking selected combinations of indolic metabolites for leaf infections with the hemibiotrophic ascomycete Colletotrichum higginsianum. Our study revealed that only camalexin, but neither indolic glucosinolates nor the recently described phytoalexin 4-hydroxy-carbonyl nitrile (4-OH-ICN) had a significant role for the resistance towards C. higginsianum. Besides its known relevance during the late necrotrophic phase, our data suggest a role of camalexin in early post-penetration defense. Our study also indicates that, indole acetonitrile (IAN) can be produced upon cleavage of indolic glucosinolate by myrosinases in pathogen challenged leaves and feed into camalexin biosynthesis in case further IAN conversion by CYP71B6 is blocked. Downstream of IAN, we found that AAO1 and CYP71B6 act redundantly in the accumulation of indole carboxylic acid (ICOOH). We also revealed that CYP71A12 has a stronger contribution to camalexin biosynthesis in C. higginsianum infected leaves than in previously investigated abiotic stress models. While our dataset suggests clear, but subtle differences in the response of the indole metabolic network in pathogen and abiotic challenge, we can rule out a contribution of the fungal pathogen to the observed differences due to our study design.
The rising incidence of Candida-associated infections and persistent antifungal resistance, driven by biofilm formation, highlight the need for alternative therapies. Essential oils offer promise as multi-targeted natural antifungals. This study evaluates the antifungal activity of Pelargonium graveolens essential oil (PGEO), obtained by hydrodistillation of aerial parts from the Edough region (Annaba, Algeria), against various Candida species and its effects on human cells. PGEO (yield: 0.23 ± 0.04% w/w) was characterized by GC-MS. Its antifungal activity was tested against five clinical Candida isolates (C. albicans, C. kefyr, C. krusei (syn. Pichia kudriavzevii), C. lusitaniae, C. tropicalis) and reference strain C. albicans ATCC 10231. Effects on virulence enzymes (secreted aspartyl protease, phospholipase, esterase, hemolysin) were assessed via Pz/Hz indices on solid media. Anti-biofilm activity was assessed using crystal violet staining and metabolic viability assays. Cytotoxicity was evaluated in HEK-293 human embryonic kidney cells. PGEO comprised mainly citronellol (28.68%), geraniol (5.35%), isomenthone (5.44%), and linalool (3.15%). It showed broad-spectrum antifungal activity (minimum inhibitory concentrations: 0.312-2.5 mg/mL; minimum fungicidal concentration/minimum inhibitory concentration ratios: 2), including against fluconazole-resistant C. krusei. At sub-inhibitory concentrations (minimum inhibitory concentration/4 to minimum inhibitory concentration/2); PGEO inhibited enzyme secretion by 21.30 to 65.00% depending on enzyme class and species ranging from 21.30% (esterase, C. krusei) to 65.00% (hemolysin, C. albicans ATCC 10231), reducing Candida adhesion and invasion. PGEO inhibited biofilm formation (48.7-97.8%) and metabolic activity (43.2-82.1% reduction at minimum inhibitory concentration). Cytotoxicity in HEK-293 cells yielded a CC50 of 3.99 ± 0.12 mg/mL, with selectivity indices of 1.59-12.79 (SI = CC50/MIC). The essential oil of Pelargonium graveolens exhibits potent fungicidal, antibiofilm, and multi-target antivirulence activities against clinically relevant Candida species, including fluconazole-resistant C. krusei, while maintaining acceptable cytotoxicity toward normal mammalian cells (CC50 = 3.99 ± 0.12 mg/mL; SI: 1.59-12.79). Its simultaneous inhibition of growth, key virulence enzymes, and biofilm formation at sub-inhibitory concentrations positions PGEO as a promising natural candidate for topical or adjunctive treatment of biofilm-associated candidiasis, pending in vivo validation.
Diabetes mellitus significantly increases susceptibility to opportunistic fungal colonization; however, the genetic architecture underlying this vulnerability in Middle Eastern populations remains underexplored. Caspase recruitment domain-containing protein 9 (CARD9) is a fundamental adaptor in fungal sensing. While CARD9 deficiency is traditionally viewed as a rare pediatric immunodeficiency, we hypothesize that common CARD9 variants serve as significant predisposing factors for fungal burden in the adult diabetic population. A cohort of 107 diabetic participants (49.5% overweight/obese) was screened for fungal colonization across multiple anatomical sites. Targeted sequencing of the CARD9 gene was performed, using a bioinformatics pipeline for heterozygous peak calling (IUPAC ambiguity codes) and Ensembl VEP for variant annotation. Functional impacts were predicted using SIFT, PolyPhen-2, and PyMOL structural modeling. Fungal colonization was prevalent, with Aspergillus niger complex (27.9%) being the most frequently identified organism. Genomic analysis identified the N-terminal CARD domain as a mutational "hotspot." We identified a high prevalence of homozygous damaging variants (52.7%), including p.Arg47His and p.Gly49Asp, which disrupt CARD domain stability. An additional 24.8% of the cohort displayed significant IUPAC-mixed heterozygous signals. Despite these genetic findings, a "paradox of stability" emerged: individuals with the highest microbial scores (4-5) often carried the reference sequence, while multivariate analysis identified obesity (OR: 1.85, p < 0.05) as the primary independent predictor of fungal burden. Our findings demonstrate that the diabetic population harbors a widespread, previously unrecognized deficiency in the Dectin-1/CARD9 signaling pathway. This shifts the clinical narrative of CARD9 from a "rare pediatric disease" to a common genetic predisposition in adult patients with diabetes. While metabolic dysregulation may override genetic factors, the high frequency of CARD domain "hotspot" mutations supports a precision medicine approach integrating CARD9 genotyping with metabolic profiling to risk-stratify patients for early antifungal prophylaxis.
Small RNAs (sRNAs) are abundant endogenous non-coding RNAs in eukaryotic organisms that regulate gene expression by binding to their target mRNAs either completely or partially. The rapid advancements in fungal sRNA research in recent years have significantly expanded our understanding of their biogenesis, functional mechanisms, and roles in fungal biology. Unlike previous reviews that predominantly focus on the intracellular biogenesis and regulatory networks of fungal sRNAs within fungal cells, this review uniquely bridges fungal sRNA molecular biology with plant pathology by centering on the bidirectional cross-kingdom RNAi trafficking between fungi and plants. We provide a comprehensive overview of fungal sRNA types, especially novel subtypes identified in recent studies, the key protein factors involved in their biogenesis, and the molecular mechanisms governing their intracellular functions. Additionally, we conduct an in-depth analysis of the trafficking routes of fungal sRNAs into host plants, their targeted interference with plant immune signaling cascades, and the reciprocal regulation of fungal physiology by plant-derived sRNAs. Finally, we discussed the potential applications of fungal sRNAs in biotechnology and pathogen control, particularly in the development of host-induced gene silencing (HIGS)/spray-induced gene silencing (SIGS)-based crop protection strategies. This work not only serves as a valuable reference for future studies on fungal sRNAs but also highlights the translational potential of cross-kingdom RNAi in plant-fungal pathosystems, filling critical gaps in existing literature.
The rapid global expansion of aquaculture has intensified the demand for sustainable and alternative lipid sources for fish feed formulations, driving interest in microbial platforms with specialized metabolic capabilities. Among these, oleaginous yeasts have emerged as promising candidates due to their ability to accumulate substantial intracellular lipid reserves and to modulate fatty acid composition in response to environmental and nutritional cues. In this study, the lipid production potential and physiological responses of two native yeast strains isolated from volcanic soils of southern Chile were investigated. The strains were identified by ITS sequencing as Solicoccozyma gelidoterrea (7C) and Rhodotorula mucilaginosa (Rho 6S). Growth kinetics, substrate utilization, and lipid accumulation were systematically evaluated under different carbon sources, carbon-to-nitrogen (C/N) ratios, and temperature regimes (7-25 °C). Response surface methodology was applied to determine the combined effects of nutritional and thermal factors on biomass production and lipid yield, while fatty acid composition was analyzed to elucidate lipid remodeling strategies. R. mucilaginosa exhibited pronounced metabolic versatility, characterized by higher maximum specific growth rates on alternative carbon sources such as xylose, sucrose, and raffinose. Under optimal conditions (25 °C and C/N 20), this strain achieved a lipid content of 30% and a biomass concentration of 2.54 g/L. In contrast, S. gelidoterrea displayed a distinct physiological profile associated with cold adaptation, reaching optimal lipid accumulation at 7 °C and C/N 20, with 26.6% lipid content and 2.11 g/L biomass. Increasing the C/N ratio to 90 significantly constrained lipid accumulation in both strains, highlighting the central role of nitrogen availability in regulating yeast lipid metabolism. Fatty acid profiling revealed clear species-specific lipid remodeling patterns: R. mucilaginosa produced a nutritionally favorable lipid profile enriched in mono and polyunsaturated fatty acids, reflected by high MUFA/SAFA and PUFA/SAFA ratios. In contrast, S. gelidoterrea exhibited a distinctive lipid profile dominated by monounsaturated fatty acids, particularly oleic acid, under nitrogen limited and low temperature conditions, and demonstrated the capacity to synthesize long chain polyunsaturated fatty acids under stress conditions, suggesting the activation of adaptive and stress responsive lipid metabolic pathways. This study provides the first evidence of lipid accumulation and fatty acid composition in S. gelidoterrea and puts into evidence contrasting lipid metabolic strategies among native oleaginous yeasts. Collectively, these findings contribute to a deeper understanding of fungal lipid physiology and environmental adaptation and support the potential of native yeast strains as sustainable lipid sources for functional foods and aquaculture nutrition.
Intercropping in olive orchards increases the risk of soil-borne fungal infections, particularly when associated crops are susceptible to the same pathogens. This study aimed to identify soil-borne microorganisms colonizing the roots and rhizosphere of olive trees in Tunisia intercropped with Solanaceae plants and to evaluate co-occurring bacterial communities for their potential to mitigate wilt disease and promote plant health. Endophytic fungi and bacteria were isolated from olive soils and roots collected from three olive orchards subjected to different intercropping systems. Fungal strains were molecularly identified at the species level using Internal Transcribed Spacer (ITS) and translation elongation factor 1-α (TEF1) gene sequencing, while bacterial strains were characterized by rep-PCR profiling and 16S rDNA sequencing. The pathogenicity of selected Fusarium strains was assessed by in vitro inoculation of detached olive leaves, olive twigs, and tomato seedlings. Antagonistic activity of bacterial strains against selected Fusarium species was evaluated using dual-culture assays, and bacteria-fungi interactions were further investigated by scanning electron microscopy (SEM). A total of 83 fungal and 40 bacterial strains were isolated. The fungal community was dominated by Fusarium species (62%), followed by Phoma (13%) and Alternaria (10%) species, while Verticillium dahliae was not detected at any site. The prevalence and virulence of Fusarium varied among olive groves, with the highest incidence observed at Sidi Bou Ali, where olive trees were intercropped with tomato, and the lowest at Kairouan, where potato intercropping was less frequent. Pathogenicity assays showed that 12 out of 15 of the tested Fusarium strains caused symptoms on both olive tissues and tomato seedlings. Bacterial communities were dominated by Bacillus species and Priestia megaterium. Bacillus species were particularly abundant at the site with the highest Fusarium pressure. The in vitro assay showed that several bacteria exhibited antagonistic activity against pathogenic fungi, with growth inhibition ranging from 8% to 68%, including volatile organic compound-mediated effects. SEM analyses revealed that Bacillus amyloliquefaciens inhibited fungal growth through biofilm formation and hyphal alteration.
Talaromycosis, caused by the dimorphic fungus Talaromyces marneffei, is a significant opportunistic infection in HIV/AIDS patients in Southeast Asia. This study aimed to investigate the antifungal susceptibility of clinical T. marneffei strains (from HIV-positive and HIV-negative patients) and non-clinical strains, and to compare their adaptability to various stress conditions. A total of 196 T. marneffei strains were assessed using broth microdilution and Sensititre YeastOne YO10 methods to determine MICs against nine antifungal agents. Stress adaptability was evaluated using 20 randomly selected non-clinical and 20 clinical strains incubated under KCl, Congo red (CR), H2O2, and Calcofluor white (CFW). Azole antifungals (itraconazole, voriconazole, posaconazole) exhibited low MICs, indicating strong activity; Clinical strains showed higher geometric mean MICs for most antifungals than non-clinical strains. Non-clinical strains showed significantly less adaptability to stress than clinical strains under CR, H2O2, and CFW (p<0.05), with smaller colony diameters and slower growth. These findings suggest that non-clinical strains may undergo phenotypic adaptations when infecting human hosts, enhancing their resilience to environmental factors and immune pressures. Antifungal susceptibility was not associated with HIV status or patient age, but linked to host adaptation.
Mangrove ecosystems are biodiversity hotspots and vital carbon sinks, yet their fungal communities-key drivers of nutrient cycling and ecosystem resilience-remain largely unexplored in the Neotropics. This is particularly true for Ecuador's protected reserves, where no molecular census of sediment fungi exists. To address this gap, we conducted the first metabarcoding survey of the fungal microbiome in the sediments of the Reserva Ecológica Manglares Churute (REMC), a critical mangrove habitat under increasing anthropogenic pressure. This is the first molecular study to characterize fungal communities in the mangrove sediments of the Reserva Ecológica Manglares Churute (REMC) in the neotropical context of Ecuador, using metabarcoding. The fungal community was dominated by Ascomycota (68%) and Basidiomycota (30%), with minor contributions from Mortierellomycota, Chytridiomycota, and Mucoromycota (<0.1%), and 2.10% unclassified at the phylum level. The most diverse sample (2005L2-69) had a Shannon index of 2.166. Rarefaction curves indicated that additional sampling could reveal more fungal diversity. Fungal assemblages were similar across samples, with minor variations linked to environmental factors. Predominant classes included Dothideomycetes, Agaricomycetes, and Eurotiomycetes. At the genus level, Ascochyta (27%), Antrodia (24%), and Talaromyces (17%) were the most abundant. The presence of genera such as Talaromyces and Penicillium highlights their biotechnological potential, like antibacterial properties. At the same time, the abundance of Ascochyta, a phytopathogen, suggests potential stress or disease susceptibility in this area of REMC. This research provides an essential preliminary overview of the mycobiome in this underexplored region and identifies principal taxa of ecological and biotechnological importance. Furthermore, this investigation, conducted in a specific area of REMC sediments, employs metabarcoding analysis utilizing ITS86-ITS4 primers in Neotropical mangroves, thereby contributing to the global understanding of mangrove microbiomes.
Rice false smut (RFS), caused by Ustilaginoidea virens (teleomorph: Villosiclava virens), has emerged as a major global threat to rice production, causing reductions in yield, grain quality, and market value. Although first reported in India in the 1870s, genomic resources for this pathogen remain limited, constraining efforts toward understanding pathogen diversity and developing effective disease management strategies. In the present study, a high-quality whole-genome sequence of the Eastern Indian U. virens isolate NRRI-FSM-1 was generated and analyzed. Comparative whole-genome sequence (WGS) analysis was further performed using six U. virens strains to investigate genomic diversity, structural variation, and candidate pathogenicity-related features. The assembled NRRI-FSM-1 genome was 36.3 Mb in size, comprising 985 scaffolds with an N50 of 5,781,932 bp. A total of 328,782 variants were identified, including 302,430 SNPs, 13,224 insertions, and 13,128 deletions. Additionally, 5,977 simple sequence repeats (SSRs) and 9,257 protein-coding genes were identified, representing the highest number of predicted genes reported so far among false smut genomes. Comparative genomics revealed substantial genomic diversity among the six strains, including variation in candidate effector repertoires, gene content, and population structure at both global and intra-Indian levels. Notably, significant diversity was observed among Indian strains, indicating considerable genomic variation across geographical regions. These findings expand the pathogenomic resource base for U. virens in India and globally, and provide insights into genome evolution and genetic plasticity in this important rice pathogen. The generated genomic resource establishes a foundation for future studies on pathogen surveillance, virulence mechanisms, and molecular breeding strategies for rice false smut management.
Scedosporium apiospermum is an emerging opportunistic fungal pathogen, primarily affecting immunocompromised individuals. Notably, it ranks second among filamentous fungi infecting cystic fibrosis (CF) patients. Infections caused by S. apiospermum can range from localized infections to pulmonary colonization and invasive disseminated infections, often resulting in high mortality rates. This is largely attributed to the patient's clinical condition, limited diagnostic tools, and resistance to current antifungal therapies. Therefore, ongoing research is crucial to better understand the pathophysiology of these deep-seated fungal infections and to develop new strategies for early diagnosis and more effective antifungal treatments. In the present study, the Δsch9 gene, which encodes a major effector of the TOR pathway in fungi, was characterized. The deletion of sch9 significantly impaired S. apiospermum fitness under standard growth conditions and reduced hyphal development. Additionally, the Δsch9 mutant strain displayed increased sensitivity to oxidative stress and cell wall stress-inducing agents. The mutant strain showed an increase in germ tube formation during the early hours of growth, particularly under hypoxic and hypercapnic conditions. Furthermore, under standard growth conditions, the Δsch9 mutant strain exhibited a decrease in germ tube cell wall thickness compared to the Δku70 parent strain. Finally, disruption of Δsch9 affected the S. apiospermum ability to resist ingestion and killing by macrophages. Taken together, these findings suggest that Sch9 plays a crucial role in stress tolerance, morphogenesis, and host-pathogen interactions in S. apiospermum. Further studies are needed to explore Sch9 as a potential therapeutic target in the treatment of S. apiospermum infections.
Light represents a major environmental factor influencing the growth, developmental programming, and metabolic regulation of Hericium erinaceus. Different wavelengths differentially affect mycelial development, stress responses, and protein expression, highlighting the complexity of fungal photoregulation. However, the molecular mechanisms and light-responsive regulatory networks in H. erinaceus remain largely unclear, limiting our understanding of how specific light cues shape its proteomic profiles. A label-free LC-MS/MS quantitative proteomics approach was employed to investigate the global protein expression profiles of H. erinaceus mycelia growing under different light treatments, including blue, green, red, and RGB qualities, compared to control (darkness). The differentially expressed proteins (DEPs) were subsequently annotated and analyzed using the Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) databases. In this study, a total of 4,618 proteins were identified in H. erinaceus, of which 560 were expressed across all experimental conditions. Comparative proteomic analysis under different light treatments revealed 550-677 DEPs per condition, with the blue-light treatment exhibiting the greatest number of uniquely expressed proteins. Light exposure modulated GO-enriched metabolic, biosynthetic, and enzymatic functions in H. erinaceus. RGB induced the broadest responses, while blue, green, and red produced distinct wavelength-specific regulatory patterns. KEGG pathway analysis showed wavelength-dependent proteomic shifts in H. erinaceus, with RGB inducing the strongest metabolic and signaling responses, while blue, green, and red differentially activated energy, biosynthesis, and regulatory pathways. These results support the molecular-mechanistic approach employed and offer valuable insights into protein expression dynamics and regulatory pathways, while also clarifying how different light qualities influence the developmental processes of H. erinaceus.
The eruption of Wudalianchi Volcano directly damaged the soil and vegetation, forcing succession to restart from bare land. It influenced subsequent vegetation succession. This study utilizes the Wudalianchi volcanic lava plateaus as a model, employing high-throughput sequencing to unravel the drivers of soil fungal diversity across a vegetation gradient: moss (M), herb (H), shrub (S), broadleaf forest (B), and mixed coniferous-broad-leaved forest (C). This study found that Ascomycota (43.39%-71.54%) and Basidiomycota (5.36%-53.21%) were the dominant phyla. Ascomycota peaked in the C community, whereas Basidiomycota was most abundant in the M community. At the genus level, Cortinarius, Mortierella, and Scleroderma dominated in the B, H, and M communities, respectively. For fungal communities, Shannon and Chao indices followed the order: S > H > C > M > B. Co-occurrence network analysis indicated the greatest complexity and connectivity in the S community, which had the most nodes, links, and the highest average degree. Fungal functional guilds shifted across the gradient: symbiotrophic fungi prevailed in the B and M, while saprotrophic fungi dominated H and C communities. Soil physicochemical properties were the primary determinants of fungal community structure and function. In conclusion, significant differences exist in the structure, diversity, and function of soil fungal communities across different vegetation types in volcanic lava habitats. Soil TP, pH, and N/P ratio were identified as key drivers, with shrub vegetation playing a critical role in fostering complex fungal networks and functional balance. This study underscores the key regulatory role of specific soil properties and vegetation succession in shaping fungal communities, providing a framework for understanding microbial assembly in extreme environments.
Fusarium-related mycotoxins are a major concern in livestock feeds due to their toxicity and potential for co-occurrence, which can cause additive or synergistic effects. This study investigated the influence of temperature and moisture content on fusarium-associated mycotoxin production in pig and broiler feeds. Feeds were inoculated with the Fusarium graminearum and incubated under controlled temperatures (30-40 °C) and moisture levels (8-15%), and mycotoxins including deoxynivalenol (DON), Fusarenone-X (FUX), fumonisins B1 and B2 (FB1, FB2), ochratoxin A (OTA), T-2 toxin, HT-2 toxin, and zearalenone (ZEN) were quantified using LCMS. Results showed that temperature was the primary driver of mycotoxin production, while moisture content modulated mycotoxin magnitude and diversity in a feed-dependent manner. In pig feed, fumonisins were predominantly produced at 30 °C under low moisture, with FB1 reaching 1850 µg/kg. DON and FUX were detected across a wider temperature range, whereas ZEN remained relatively stable. OTA, T-2, and HT-2 toxins were infrequently detected. Broiler feed showed similar patterns, with DON and FUX consistently present, fumonisins largely restricted to lower temperatures, and ZEN stable across conditions. Co-occurrence of multiple mycotoxins was most pronounced at lower temperatures, highlighting the risk of chronic multi-toxin exposure. Overall, these findings emphasize the importance of optimized feed storage and multi-mycotoxin monitoring. Feed-specific mitigation strategies, including antifungal additives or plant-derived bioactive compounds, may help reduce mycotoxin accumulation and safeguard livestock health and productivity.
Volcanic eruptions deposit lava that covers the original soil and alters biogeochemical cycles, leading to the formation of unique ecological characteristics. Litter decomposition is an important part of the nutrient cycling in volcanic forest ecosystems. This study aimed to investigate the dynamic coupling between litter nutrient release and fungal community succession during the decomposition of pioneer Betula platyphylla in a volcanic forest. We conducted an in situ decomposition experiment combined with Illumina MiSeq high-throughput sequencing and fungal functional prediction. We found that, on the lava plateau, after 18 months of decomposition, Betula platyphylla litter remains in the early stages of decomposition, with rapid changes occurring in its nutrient composition and fungal community structure. (p < 0.05). The diversity and composition of fungal communities in Betula platyphylla litter differed significantly among the four sampling periods. The succession of fungal communities, dominated by Ascomycota and Basidiomycota, was primarily driven by changes in litter mass remaining and key nutrient concentrations (C, N and P). Our results offer valuable insights for further investigations into the dynamics of fungal communities during litter decomposition in volcanic forest ecosystems.
The role of cyclic AMP-protein kinase A (PKA) signaling in siderophore-mediated iron uptake and its connection to virulence remains poorly understood in phytopathogenic fungi. Genetic studies demonstrate that the A. alternata adenylate cyclase (AaAC) regulates diverse cellular processes, including growth, conidiation, iron homeostasis, autophagy, siderophore biosynthesis, and toxin production. Deletion of AaAC results in impaired siderophore secretion, disrupted expression of iron-responsive genes, and a complete loss of ACT toxin biosynthesis, leading to markedly reduced virulence. Transcriptomic analysis under iron-deficient conditions reveals that AaAC deletion induces widespread changes in gene expression, notably the downregulation of genes involved in siderophore biosynthesis and ACT toxin production. These findings indicate that AaAC regulates metabolic pathways essential for fungal survival and pathogenicity. Mutants lacking the GTP-binding protein alpha subunit (Gα), the PKA catalytic subunit, or its regulatory subunit also reduce siderophore production. The findings suggest that environmental cues influencing siderophore biosynthesis are transmitted via a signaling cascade from Gα to AaAC and then to PKA. Additionally, AaAC negatively affects autophagy under nutrient-rich conditions. Gene ontology analysis reveals upregulation of autophagy-related genes, suggesting that AaAC may contribute to cellular energy preservation and physiological stability. These results indicate that AaAC is a key integrator of environmental signals, vital for maintaining iron homeostasis, controlling toxin biosynthesis, and driving virulence in A. alternata.
The changing epidemiology of candidemia indicates a rise in non-albicans Candida species, especially resistant Candida auris and emerging Candida utilis. Although iron impacts fungal virulence, its role in these species remains poorly understood. This study investigates how manipulating iron levels influences biofilm formation, virulence enzymes, and antifungal susceptibility in clinical isolates. A total of 216 isolates of Candida utilis, Candida albicans, and Candida auris from bloodstream infections over two years were identified via phenotypic methods, MALDI-TOF MS, VITEK 2, and 18S rRNA PCR. Susceptibility was tested using disc diffusion and broth microdilution with ferrous sulphate (FeSO4). Virulence enzyme activities and biofilm formation were assessed under iron-rich and control conditions. Candida auris showed multidrug resistance, especially to fluconazole and caspofungin, with iron increasing caspofungin MICs up to 16-fold. Candida utilis exhibited strong biofilm formation and increased phospholipase and proteinase activities in the presence of FeSO4, and also showed 4- to 32-fold increases in fluconazole resistance. Biofilm biomass was unaffected by iron, but enzyme activities varied by species and enzyme. Candida albicans had high proteinase and haemolysin activity but responded minimally to iron. Iron differentially influences virulence-associated traits (biofilm-related enzyme activities) and antifungal resistance across these Candida species. C. utilis exhibits iron-responsive increases in phospholipase and proteinase activities together with amplified azole resistance, while C. auris shows iron-linked enhancement of echinocandin resistance and sustained expression of key virulence-associated enzymes. These results underscore the importance of accounting for host iron levels and species-specific responses when managing candidemia and indicate the potential for therapies targeting iron.
Mould spoilage is a major challenge in bakery production, yet the sources and persistence of contaminating strains remain poorly understood. We applied whole-genome sequencing (WGS) to 68 isolates from potato-cereal wraps and their production environment in a Norwegian bakery. Barcode-based identification using ITS, BenA, CaM, and RPB2 confirmed that 65 isolates belonged to the Penicillium commune/Penicillium fuscoglaucum lineage but could not fully resolve species status or resolve strain-level differences. Genome-wide comparison using Mash placed these isolates in a single clade within series Camembertiorum, distinct from cheese-associated taxa. SNP analysis revealed extremely low diversity within the main cluster (up to 60 SNPs after recombination filtering) and demonstrated that genetically similar strains persisted in the facility for 15 months, spanning multiple products and environmental samples. No consistent association with potato suppliers or production dates was detected, indicating that long-term environmental reservoirs were the main source of contamination. These findings show that persistent clonal lineages can survive routine cleaning in dry bakery environments, enabling recurrent contamination. WGS provided the strain-level resolution needed to uncover this persistence and clarify phylogenetic placement, underscoring its value for monitoring and controlling mould spoilage in food production.
Beauveria bassiana (Balsamo) Vuillemin is a well-known entomopathogenic fungus that occupies diverse ecological niches, including soilborne, epiphytic, and endophytic habitats. Its capacity to function as an endophyte has received growing interest in potential applications for sustainable pest management, particularly in woody perennial systems where delivery and persistence of biological control agents are challenging. This study investigated endophytic colonization of peach (Prunus persica Batsch) seedlings by B. bassiana and quantified production of the insecticidal secondary metabolite beauvericin (BEA) in and on plant tissues. Seedlings were inoculated via foliar spray or soil drench. Fungal recovery was assessed from leaf, stem, and root tissues. Colonization patterns indicated systemic movement, however foliar spray increased recovery from leaf tissues and soil drench increased recovery from roots over time. BEA concentrations varied significantly by tissue type, inoculation method, and surface sterilization status. The highest levels were detected in non-surface-sterilized leaves of foliar-sprayed plants, measured two weeks post-inoculation. Surface sterilization prior to extraction significantly reduced detected concentrations, suggesting that BEA is primarily produced by epiphytic fungal growth. Larval bioassays with Tenebrio molitor L. revealed increased mortality associated with foliar-sprayed tissues, aligning with observed BEA levels and suggesting localized insecticidal activity. These findings demonstrate that the spatial dynamics of fungal colonization and metabolite localization are critical considerations for the effective deployment of B. bassiana in biocontrol strategies. Further research is needed to determine how environmental factors, host physiology, fungal strain, and time influence secondary metabolite production in and on plants treated with B. bassiana.
Chitosan-copper nanoparticles (CHT-Cu NPs) were synthesized using an ionic gelation approach and evaluated for their physicochemical properties and antifungal activity against major fungal pathogens of chickpea and citrus. For instance, "In recent years, nanotechnology-based formulations have emerged as promising strategy for sustainable disease management". Dynamic light scattering analysis revealed uniformly sized nanoparticles (~150 nm) with low polydispersity and a positive surface charge (+22.2 mV). Fourier transform infrared spectroscopy, X-ray diffraction, scanning and transmission electron microscopy, and energy-dispersive X-ray analysis confirmed effective copper coordination, amorphous nanocomposite formation, and stable incorporation of copper within the chitosan matrix. The antifungal efficacy of CHT-Cu NPs was assessed in vitro against Colletotrichum ciceri, Fusarium ciceri, Rhizoctonia bataticola, Sclerotium rolfsii, and Colletotrichum gloeosporioides. The nanocomposites exhibited strong, concentration-dependent inhibition of mycelial growth. F. ciceri was highly sensitive, showing complete inhibition at all tested concentrations (≥100 µg mL-¹). S. rolfsii and chickpea pathogens C. ciceri and R. bataticola were completely inhibited at concentrations 200 µg mL-¹, 300 µg mL-¹ and 300 µg mL-¹, respectively, whereas C. gloeosporioides was comparatively less sensitive and required higher concentrations (≥400 µg mL-¹) for complete suppression. In contrast, chitosan alone and copper sulfate showed only moderate antifungal activity. These findings demonstrate that CHT-Cu NPs possess broad-spectrum antifungal activity and superior efficacy compared to conventional fungicides, highlighting their potential as eco-compatible nanobiopesticides for sustainable management of fungal diseases in crop plants.
Oudemansiella apalosarca, a newly identified edible fungus, exhibits industrial cultivation potential because of its short production cycle and lack of a casing layer. However, the absence of genomic data has hampered its development and varietal enhancement. This study reports the first genome sequence of O. apalosarca, comprising 53.13 Mb across 27 scaffolds and 14,650 protein-coding genes, with superior scaffold N50 and BUSCO values compared to those of other Oudemansiella genomes. Phylogenetic analysis of single-copy orthologous proteins from 25 fungal genomes revealed close relations to O. raphanipes and Mucidula mucidula, with significant protein collinearity within the Physalacriaceae family. Cultivation in complete darkness yielded pure white, small-cap, and long-stipe fruiting bodies, indicating industrial advantages. Differential transcriptome analysis of the cap and stipe under varying light conditions identified key genes and pathways regulating phenotypic changes. Kyoto Encyclopedia of Genes and Genomes (KEGG) assessment and gene set enrichment analysis (GSEA) revealed significant negative regulation of DNA replication pathway genes in the cap, with the downregulation of 10 cell cycle and mismatch repair genes. Genes related to cell wall formation and carbon metabolism were upregulated, thus promoting stipe elongation. The tyrosine metabolism pathway influenced cap coloration, with tyrosinase identified as a multicopy gene. Phylogenetic analysis revealed diverse evolutionary origins. Key tyrosinase-related genes A6_A10477 and A6_A09603 were overexpressed in the light, revealing their role in melanin formation. In summary, this study provides genomic resources for O. apalosarca breeding improvement and elucidates light-induced regulatory mechanisms in its development, thereby providing theoretical and technical support for industrial applications.