Search Results (57)

Fungal infections are a major but often neglected global health challenge, affecting both human health and agricultural productivity. Current treatments are limited by few drug classes and increasing multidrug resistance, exacerbated by the widespread use of antifungal agents in clinical and agricultural settings. This study investigates the antifungal potential of a novel 8-hydroxyquinoline derivative with a triazole core at the 5-position, synthesized to improve both efficacy and mechanistic understanding as a fluorescent chemical probe. Biological assays demonstrated significant antifungal activity of compound 10 against a range of pathogens, which was active against all Candida species, dermatophytes, and Fusarium solani with MIC values ranging from 0.5 to 4 µg/mL. Confocal fluorescence microscopy of treated fungal cells was conducted and showed a high accumulation of compound 10 at the cell edge. To further investigate the mode of action, results from a sorbitol protection assay suggested a possible cell wall action, and scanning electron microscopy (SEM) revealed cell wall disruption, such as cell shrinkage and surface roughness, in treated fungal cells. These findings highlight the 8-hydroxyquinoline-triazole scaffold as a promising antifungal agent with cell wall damage properties, providing a basis for future therapeutic development against human and plant fungal pathogens. Full article

Barley leaf stripe, caused by Pyrenophora graminea, significantly reduces yield. Polygalacturonase, a key fungal pectinase, facilitates cell wall degradation for nutrition acquisition and colonization. To determine whether P. graminea contains polygalacturonase (PgPG)-encoding genes and their role in pathogenicity, four PgPG genes (PgPG1–PgPG4) were identified in the P. graminea genome. Quantitative RT-PCR revealed that PgPG1 had the highest inducible expression during barley infection, suggesting its critical vital role in pathogenesis. PgPG1 was silenced and overexpressed in P. graminea QWC (wild-type) using CaCl₂-PEG4000-mediated protoplast transformation. The PgPG1 RNAi mutants exhibited slower growth, while overexpression mutants grew faster. Relative to the wild-type, the disease incidence of Alexis, a highly susceptible barley variety, decreased by 62.94%, 42.19%, 45.74%, and 40.67% for RNAi mutants, and increased by 12.73%, 12.10%, 12.63%, and 10.31% for overexpression mutants. Pathogenicity analysis showed decreased disease incidence with PgPG1 RNAi mutants and increased severity with overexpression mutants. Trypan blue staining and polygalacturonase activity assays confirmed that overexpression mutants caused more severe damage compared to wild-type and RNAi mutants. These findings indicate that PgPG1 plays a vital role in the pathogenicity of P. graminea in barley and has great potential as a pathogen target gene to develop a durable resistance variety to P. graminea. Full article

The growing emergence of resistance mechanisms and side effects associated with antifungal agents highlight the need for alternative therapies. This study aims to investigate the antifungal potential of ozonated extra-virgin olive oil (EOO) against Candida albicans, with the goal of developing eco-friendly and highly effective treatments based on natural products. Antifungal activity was evaluated via cell viability and biofilm formation assays using Crystal Violet and Sytox green staining. The results showed that EOO reduced C. albicans viability in a dose-dependent manner, achieving over 90% cell death at a 3% (v/v) concentration. Transmission Electron Microscopy (TEM) revealed cell wall structural damage, and ROS levels increased by approximately 60% compared to untreated controls within 10 min of treatment. Additionally, the expression of autophagy-related genes atg-7 and atg-13was upregulated by 2- and 3.5-fold, respectively, after 15 min, suggesting a stress-induced cell death response. EOO also significantly inhibited hyphal formation and biofilm development, thus reducing C. albicans pathogenicity while preserving cell biocompatibility. EOO antifungal activity was also observed in the case of Candida glabrata. In conclusion, ozonated olive oil demonstrates potent antifungal activity against C. albicans by reducing cell viability, inhibiting hyphal and biofilm formation, and triggering oxidative stress and autophagy pathways. These findings position EOO as a promising alternative therapy for fungal infections. Full article

Fungi play irreplaceable roles in the functioning of natural ecosystems, but global warming poses a significant threat to them. However, the mechanisms underlying fungal tolerance to thermal and UV-B stresses remain largely unknown. Dual-specificity tyrosine phosphorylation-regulated kinase (DYRK) Pom1 is crucial for fungal growth, conidiation, and virulence. However, its role in stress tolerance within kingdom fungi has not been explored. In this study, we analyzed the function of MaPom1 (a Pom1 homologous gene) in the entomopathogenic fungus Metarhizium acridum and its regulatory roles in stress tolerance. Conidial thermal and UV-B tolerance significantly decreased in the MaPom1 disruption strain (ΔMaPom1), whereas conidial yield and virulence were unaffected. RNA-Seq analysis indicated that the differentially expressed genes (DEGs) were primarily related to amino sugar, nucleotide sugar metabolism, cell wall components, growth and development, and stress response pathways. Under heat shock treatment, the expression levels of heat shock protein genes decreased significantly, leading to reduced thermotolerance. Moreover, under UV-B treatment, MaPom1 expression and the enzyme activity significantly changed, indicating its involvement in regulating UV-B tolerance. The percentage of nuclear damage in ΔMaPom1 under UV-B treatment was higher than that in the wild-type strain (WT) and the complementary strain (CP). Additionally, the transcription levels of DNA damage-related genes significantly decreased, whereas those of several genes involved in the DNA damage repair response increased significantly. Overall, MaPom1 contributed to thermal and UV-B tolerance by regulating the expression of heat shock protein genes and DNA damage repair genes. Full article

Rice blast, caused by the filamentous fungus Pyricularia oryzae, has long been one of the major threats to almost all rice-growing areas worldwide. Metconazole, 5-(4-chlorobenzyl)-2, 2-dimethyl-1-(1H-1, 2, 4-triazol-1-ylmethyl) cyclopentanol, is a lipophilic, highly active triazole fungicide that has been applied in the control of various fungal pathogens of crops (cereals, barley, wheat), such as the Fusarium and Alternaria species. However, the antifungal activity of metconazole against P. oryzae is unknown. In this study, metconazole exhibited broad spectrum antifungal activities against seven P. oryzae strains collected from rice paddy fields and the wild type strain P131. Scanning electron microscopic analysis and fluorescein diacetate staining assays revealed that metconazole treatment damaged the cell wall integrity, cell membrane permeability and even cell viability of P. oryzae, resulting in deformed and shrunken hyphae. The supplementation of metconazole in vitro increased fungal sensitivity to different stresses, such as sodium dodecyl sulfate, congo red, sodium chloride, sorbitol and oxidative stress (H₂O₂). Metconazole could inhibit key virulence processes of P. oryzae, including conidial germination, germ tube elongation and appressorium formation. Furthermore, this chemical prevented P. oryzae from infecting barley epidermal cells by disturbing appressorium penetration and subsequent invasive hyphae development. Pathogenicity assays indicated a reduction of over 75% in the length of blast lesions in both barley and rice leaves when 10 μg/mL of metconazole was applied. This study provides evidence to understand the antifungal effects of metconazole against P. oryzae and demonstrates its potential in rice blast management. Full article

Alternaria leaf spot seriously threatens the sustainable development of the global apple industry, causing significant losses and reducing fruit quality and yield. The causal agent Alternaria alternata f. sp. mali (Alternaria mali, ALT) produces various molecules to modulate infection, such as cell wall-degrading enzymes, toxins, and elicitor-like molecules. ALT produces the host-specific AM-toxin, an important pathogenicity factor. ALT also releases effectors into apple cells that modify host defense, but these proteins have not yet been described. Here, we identified the pathogenic fungal types responsible for early defoliation from diseased leaves of Fuji (Malus domestica cv. ‘Fuji’) apple collected from five districts in Shandong Province, China. The ALT isolates ALT2 to ALT7 were pathogenic to four apple cultivars, with ALT7 being the most aggressive. We extracted mycotoxins (AM-toxin-2 to AM-toxin-7) from each isolate and used them to treat different apple varieties, which led to leaf-spot symptoms and damaged chloroplasts and nuclear membranes, followed by cell death. AM-toxin-7 produced the most severe symptoms, but chloroplasts remained intact when the mycotoxin was inactivated. Mass spectrometry identified 134 secretory proteins in ALT7 exosomes, and three secreted proteins (AltABC, AltAO, and AltPDE) were confirmed to be involved in apple pathogenesis. Therefore, ALT secretes AM-toxin and secretory proteins as an infection strategy to promote fungal invasion and overcome the host defense system. Full article

Ageritin from poplar mushrooms is a specific endonuclease that hydrolyzes a single phosphodiester bond located in the sarcin-ricin loop (SRL) of the large rRNA, thereby blocking protein synthesis. Considering the possible biotechnological use of this enzyme, here we report its antifungal activity against virulent fungi affecting crops of economic interest. Our results show that ageritin (200 µg/plug; ~13.5 nmole) inhibits the growth of Botrytis cinerea (57%), Colletotrichum truncatum (42%), and Alternaria alternata (57%), when tested on potato dextrose agar plates. At the same time, no effect was observed against Trichoderma harzianum (a fungus promoting beneficial effects in plants). To verify whether the antifungal action of ageritin against B. cinerea and T. harzianum was due to ribosome damage, we tested ageritin in vitro on partially isolated B. cinerea and T. harzianum ribosomes. Interestingly, ageritin was able to release the Endo’s fragment from both tested fungal ribosomes. We therefore decided to test the antifungal effect of ageritin on B. cinerea and T. harzianum using a different growth condition (liquid medium). Differently from the result in solid medium, ageritin can inhibit both B. cinerea and T. harzianum fungal growth in liquid medium in a concentration-dependent manner up to 35.7% and 38.7%, respectively, at the highest concentration tested (~200 µg/mL; 12 µM), and the analysis of RNA isolated from ageritin-treated cells revealed the presence of Endo’s fragment, highlighting its ability to cross the fungal cell wall and reach the ribosomes. Overall, these data highlight that the efficacy of antifungal treatment to prevent or treat a potential fungal disease may depend not only on the fungal species but also on the conditions of toxin application. Full article

Withania chevalieri, endogenous from Cape Verde, is a medicinal plant used in ethnomedicine with a large spectrum of applications, such as treating skin fungal infections caused by dermatophytes. The aim of this work was to chemically characterize the W. chevalieri crude ethanolic extract (WcCEE), and evaluate its bioactivities as antidermatophytic, antioxidant, anti-inflammatory and anticancer, as well as its cytotoxicity. WcCEE was chemically characterized via HPLC–MS. The minimal inhibitory concentration, minimal fungicidal concentration, time-kill and checkerboard assays were used to study the antidermatophytic activity of WcCEE. As an approach to the mechanism of action, the cell wall components, β-1,3-glucan and chitin, and cell membrane ergosterol were quantified. Transmission electron microscopy (TEM) allowed for the study of the fungal ultrastructure. WcCEE contained phenolic acids, flavonoids and terpenes. It had a concentration-dependent fungicidal activity, not inducing relevant resistance, and was endowed with synergistic effects, especially terbinafine. TEM showed severely damaged fungi; the cell membrane and cell wall components levels had slight modifications. The extract had antioxidant, anti-inflammatory and anti-cancer activities, with low toxicity to non-tumoral cell lines. The results demonstrated the potential of WcCEE as an antidermatophytic agent, with antioxidant, anti-inflammatory and anticancer activity, to be safely used in pharmaceutical and dermocosmetic applications. Full article

The gaseous reactive oxygen/nitrogen species (RONS) generated by cold atmospheric plasma (CAP) can effectively inactivate Aspergillus flavus (A. flavus) and prolong the shelf-life of food. Plasma-activated water (PAW) is the extension of cold plasma sterilization technology. Without the limitation of a plasma device, PAW can be applied to more scenarios of food decontamination. However, the efficacy of PAW as a carrier of RONS for eradicating A. flavus or inhibiting its growth remains unclear. In this study, the immediate fungicidal effect and long-term inhibitory effect of PAW on A. flavus were investigated. The results demonstrated that 60-min instant-prepared PAW could achieve a 3.22 log reduction CFU/mL of A. flavus and the fungicidal efficacy of PAW gradually declined with the extension of storage time. Peroxynitrite (ONOO⁻/ONOOH) played a crucial role in this inactivation process, which could damage the cell wall and membrane structure, disrupt intracellular redox homeostasis, and impair mitochondrial function, ultimately leading to fungal inactivation. In addition to the fungicidal effect, PAW also exhibited fungistatic properties and inhibited the synthesis of aflatoxin B₁ (AFB₁) in A. flavus. By analyzing the cellular antioxidant capacity, energy metabolism, and key gene expression in the AFB₁ synthesis pathway, it was discovered that PAW can significantly reduce ATP levels, while increasing SOD and CAT activity during 5-d cultivation. Meanwhile, PAW effectively suppressed the expression of genes related to AFB₁ synthesis. Full article

Candida albicans is an opportunistic human fungal pathogen, and its drug resistance is becoming a serious problem. Camellia sinensis seed saponins showed inhibitory effects on resistant Candida albicans strains, but the active components and mechanisms are unclear. In this study, the effects and mechanisms of two Camellia sinensis seed saponin monomers, theasaponin E1 (TE1) and assamsaponin A (ASA), on a resistant Candida albicans strain (ATCC 10231) were explored. The minimum inhibitory concentration and minimum fungicidal concentration of TE1 and ASA were equivalent. The time–kill curves showed that the fungicidal efficiency of ASA was higher than that of TE1. TE1 and ASA significantly increased the cell membrane permeability and disrupted the cell membrane integrity of C. albicans cells, probably by interacting with membrane-bound sterols. Moreover, TE1 and ASA induced the accumulation of intracellular ROS and decreased the mitochondrial membrane potential. Transcriptome and qRT-PCR analyses revealed that the differentially expressed genes were concentrated in the cell wall, plasma membrane, glycolysis, and ergosterol synthesis pathways. In conclusion, the antifungal mechanisms of TE1 and ASA included the interference with the biosynthesis of ergosterol in fungal cell membranes, damage to the mitochondria, and the regulation of energy metabolism and lipid metabolism. Tea seed saponins have the potential to be novel anti-Candida albicans agents. Full article

Various proteins introduced into living modified organism (LMO) crops function in plant defense mechanisms against target insect pests or herbicides. This study analyzed the antifungal effects of an introduced LMO protein, 5-enolpyruvylshikimate-3-phosphate synthase (EPSPS) from Agrobacterium sp. strain CP4 (CP4-EPSPS). Pure recombinant CP4-EPSPS protein, expressed in Escherichia coli, inhibited the growth of human and plant fungal pathogens (Candida albicans, C. tropicalis, C. krusei, Colletotrichum gloeosporioides, Fusarium solani, F. graminearum, and Trichoderma virens), at minimum inhibitory concentrations (MICs) that ranged from 62.5 to 250 µg/mL. It inhibited fungal spore germination as well as cell proliferation on C. gloeosporioides. Rhodamine-labeled CP4-EPSPS accumulated on the fungal cell wall and within intracellular cytosol. In addition, the protein induced uptake of SYTOX Green into cells, but not into intracellular mitochondrial reactive oxygen species (ROS), indicating that its antifungal action was due to inducing the permeability of the fungal cell wall. Its antifungal action showed cell surface damage, as observed from fungal cell morphology. This study provided information on the effects of the LMO protein, EPSPS, on fungal growth. Full article

The human C-type lectin domain family 7 member A (CLEC7A) gene encodes a Dectin-1 protein that recognizes beta-1,3-linked and beta-1,6-linked glucans, which form the cell walls of pathogenic bacteria and fungi. It plays a role in immunity against fungal infections through pathogen recognition and immune signaling. This study aimed to explore the impact of nsSNPs in the human CLEC7A gene through computational tools (MAPP, PhD-SNP, PolyPhen-1, PolyPhen-2, SIFT, SNAP, and PredictSNP) to identify the most deleterious and damaging nsSNPs. Further, their effect on protein stability was checked along with conservation and solvent accessibility analysis by I-Mutant 2.0, ConSurf, and Project HOPE and post-translational modification analysis using MusiteDEEP. Out of the 28 nsSNPs that were found to be deleterious, 25 nsSNPs affected protein stability. Some SNPs were finalized for structural analysis with Missense 3D. Seven nsSNPs affected protein stability. Results from this study predicted that C54R, L64P, C120G, C120S, S135C, W141R, W141S, C148G, L155P, L155V, I158M, I158T, D159G, D159R, I167T, W180R, L183F, W192R, G197E, G197V, C220S, C233Y, I240T, E242G, and Y3D were the most structurally and functionally significant nsSNPs in the human CLEC7A gene. No nsSNPs were found in the predicted sites for post-translational modifications. In the 5′ untranslated region, two SNPs, rs536465890 and rs527258220, showed possible miRNA target sites and DNA binding sites. The present study identified structurally and functionally significant nsSNPs in the CLEC7A gene. These nsSNPs may potentially be used for further evaluation as diagnostic and prognostic biomarkers. Full article

This research aimed to investigate natamycin’s antifungal effect and its mechanism against the chestnut pathogen Neofusicoccum parvum. Natamycin’s inhibitory effects on N. parvum were investigated using a drug-containing plate culture method and an in vivo assay in chestnuts and shell buckets. The antifungal mechanism of action of natamycin on N. parvum was investigated by conducting staining experiments of the fungal cell wall and cell membrane. Natamycin had a minimum inhibitory concentration (MIC) of 100 μg/mL and a minimum fungicidal concentration (MFC) of 200 μg/mL against N. parvum. At five times the MFC, natamycin had a strong antifungal effect on chestnuts in vivo, and it effectively reduced morbidity and extended the storage period. The cell membrane was the primary target of natamycin action against N. parvum. Natamycin inhibits ergosterol synthesis, disrupts cell membranes, and causes intracellular protein, nucleic acid, and other macromolecule leakages. Furthermore, natamycin can cause oxidative damage to the fungus, as evidenced by decreased superoxide dismutase and catalase enzyme activity. Natamycin exerts a strong antifungal effect on the pathogenic fungus N. parvum from chestnuts, mainly through the disruption of fungal cell membranes. Full article

Verticillium wilt is a kind of soil-borne plant fungal disease caused by Verticillium dahliae (Vd). Vd 991 is a strong pathogen causing cotton Verticillium wilt. Previously, we isolated a compound from the secondary metabolites of Bacillus subtilis J15 (BS J15), which showed a significant control effect on cotton Verticillium wilt and was identified as C17 mycosubtilin. However, the specific fungistatic mechanism by which C17 mycosubtilin antagonizes Vd 991 is not clear. Here, we first showed that C17 mycosubtilin inhibits the growth of Vd 991 and affects germination of spores at the minimum inhibitory concentration (MIC). Morphological observation showed that C17 mycosubtilin treatment caused shrinking, sinking, and even damage to spores; the hyphae became twisted and rough, the surface was sunken, and the contents were unevenly distributed, resulting in thinning and damage to the cell membrane and cell wall and swelling of mitochondria of fungi. Flow cytometry analysis with ANNEXINV-FITC/PI staining showed that C17 mycosubtilin induces necrosis of Vd 991 cells in a time-dependent manner. Differential transcription analysis showed that C17 mycosubtilin at a semi-inhibitory concentration (IC50) treated Vd 991 for 2 and 6 h and inhibited fungal growth mainly by destroying synthesis of the fungal cell membrane and cell wall, inhibiting its DNA replication and transcriptional translation process, blocking its cell cycle, destroying fungal energy and substance metabolism, and disrupting the redox process of fungi. These results directly showed the mechanism by which C17 mycosubtilin antagonizes Vd 991, providing clues for the mechanism of action of lipopeptides and useful information for development of more effective antimicrobials. Full article

Fusarium oxysporum f. sp. cubense (Foc), which causes Fusarium wilt of bananas, is considered one of the most destructive fungal pathogens of banana crops worldwide. During infection, Foc secretes many different proteins which promote its colonization of plant tissues. Although F. oxysporum has no sexual cycle, it has been reported to secrete an α-pheromone, which acts as a growth regulator, chemoattractant, and quorum-sensing signaling molecule; and to encode a putative protein with the hallmarks of fungal α-pheromone precursors. In this study, we identified an ortholog of the α-pheromone precursor gene, Foc4-PP1, in Foc tropical race 4 (TR4), and showed that it was necessary for the growth and virulence of Foc TR4. Foc4-PP1 deletion from the Foc TR4 genome resulted in decreased fungal growth, increased sensitivity to oxidative stress and cell-wall-damaging agents, and attenuation of pathogen virulence towards banana plantlets. Subcellular localization analysis revealed that Foc4-PP1 was concentrated in the nuclei and cytoplasm of Nicotiana benthamiana cells, where it could suppress BAX-induced programmed cell death. In conclusion, these findings suggest that Foc4-PP1 contributes to Foc TR4 virulence by promoting hyphal growth and abiotic stress resistance and inhibiting the immune defense responses of host plants. Full article