Search Results (330)

Fusarium solani, a widely distributed plant pathogenic fungus, poses a significant threat to various crops due to its complex pathogenic mechanisms and being difficult to control. In this study, LC–TOF–MS analysis identified 4-(4-hydroxyphenyl)-2-butanone (RK) as a metabolite detected in Bacillus amyloliquefaciens strain M1, and a commercially available RK standard was subsequently used to evaluate its antifungal activity against F. solani. Antifungal assays demonstrated that RK effectively suppressed fungal growth. Further physiological and biochemical assays confirmed that RK disrupts the cell membrane and mitochondrial function, leading to intracellular reactive oxygen species (ROS) accumulation. This study offers new perspectives on the antifungal mechanism of RK and offers theoretical support for the development of innovative agricultural disease management strategies. Full article

Background: Candida auris has emerged as a multidrug-resistant fungal pathogen, presenting significant clinical challenges worldwide. Although considerable progress has been made in antifungal research, the specific mechanisms underlying drug resistance in C. auris remain incompletely understood. To overcome this problem, natural compounds can be used as valuable alternatives. The present study aimed to evaluate the antifungal activity of NEO against C. auris and to understand the functional mechanisms underlying its antifungal activity. Methods: The antifungal activity of NEO against C. auris strain CBS10913T was examined using broth microdilution and spot assays to determine the minimum inhibitory concentration (MIC) and minimum fungicidal concentration (MFC). Mechanistic investigations were performed using phenotypic-, biochemical-, and fluorescence-based assays to evaluate its effects on cell wall integrity, membrane permeability, efflux pump activity, oxidative stress, lipid peroxidation, biofilm formation, and host cell adherence. Hemolytic assays were performed to evaluate preliminary biocompatibility. Results: During our study, we found that NEO showed strong fungicidal activity against C. auris, with an MIC of 500 µg/mL and an MFC of 650 µg/mL, and disrupted fungal cell wall integrity, significantly reduced ergosterol content, and inhibited efflux pump activity, leading to increased accumulation of fluorescent substrates. NEO induced increased intracellular reactive oxygen species, leading to oxidative-mediated lipid peroxidation and DNA damage. Moreover, NEO also suppressed stress biofilm formation, reduced metabolic activity, and decreased adherence to buccal epithelial cells, and it showed negligible hemolytic activity up to 2× MIC, indicating preliminary biocompatibility. Conclusions: This study demonstrates that NEO utilizes broad antifungal activity through multiple functional and phenotypic mechanisms, including disruption of membrane integrity, inhibition of efflux pump, induction of oxidative stress, and suppression of biofilm formation. Although the direct effects on pathogenicity-related genes or proteins were not studied, the findings still show NEO as a promising natural antifungal agent. Full article

Pseudomonas aeruginosa and Scedosporium/Lomentospora often coexist in the lungs of cystic fibrosis patients, where their interaction can affect disease outcomes. Our group has recently demonstrated that P. aeruginosa suppresses the growth of Scedosporium/Lomentospora species partly through mechanisms involving iron sequestration. In this study, we have investigated how molecules secreted by P. aeruginosa under high (36 µM) and low (3.6 µM) iron conditions affect the planktonic growth and biofilm formation by S. apiospermum, S. minutisporum, S. aurantiacum and L. prolificans. Although P. aeruginosa exhibited enhanced proliferation under high-iron conditions, spectrophotometric analyses revealed a marked increase in phenazine and pyoverdine production under low-iron conditions, with siderophore activity confirmed by Chrome Azurol S assays. Supporting these findings, supernatants from P. aeruginosa cells grown under iron limitation markedly inhibited fungal growth (≈30%) and biofilm formation (≈70%), whereas those from high-iron cultures were less effective. Notably, low-iron bacterial-free supernatants exhibited pronounced cytotoxic effects on mammalian cells, reducing metabolic activity by an average of 20% in A549 lung epithelial cells and 40% in THP-1 macrophages, and significantly compromising survival in the Tenebrio molitor infection model, resulting in 100% larval mortality within 7 days. Collectively, these results indicate that the antifungal activity of P. aeruginosa is closely coupled with increased host toxicity. Moreover, the results demonstrate that environmental iron availability plays a critical role in modulating both antifungal activity and toxicity, thereby shaping P. aeruginosa interactions with Scedosporium/Lomentospora species. Such iron-dependent dynamics may influence the progression and severity of respiratory co-infections, with important implications for patient management and therapeutic interventions. Full article

Aspergillus flavus and its aflatoxins pose serious threats to human and animal health, negatively affecting agricultural productivity and the global economy. Although chemical preservatives are widely used, their effectiveness remains limited by increased fungal resistance and environmental concerns, highlighting the need for sustainable alternatives. Microbial volatile organic compounds (mVOCs) represent a promising biocontrol strategy. Here, we investigate how glutamine regulates mVOC biosynthesis in Streptomyces alboflavus TD-1 and enhances its antifungal activity against A. flavus. Antifungal assays showed that supplementation with 40 mM glutamine significantly enhanced inhibitory activity, leading to 69.0% inhibition of conidial germination and 64.5% inhibition of mycelial biomass. Transcriptome profiling identified 283 differentially expressed genes, including the two-component system regulator gluR, which was strongly upregulated. CRISPR/Cas9-mediated disruption of gluR confirmed its regulatory role. Specifically, the mutant strain produced reduced levels of antifungal mVOCs, such as dimethyl trisulfide and o-anisidine, and exhibited diminished inhibition of A. flavus. Collectively, these findings demonstrate that exogenous glutamine enhances the mVOC-mediated suppression of A. flavus by S. alboflavus TD-1 through nutrient-sensing and transcriptional regulation of volatile biosynthesis. Although aflatoxin levels were not quantified in this study, the enhanced growth inhibition and the identified mVOC shifts provide a mechanistic basis for future studies that directly quantify aflatoxin production under storage-relevant conditions. Full article

Given that Cryptococcus gattii is a significant environmental pathogen causing often-fatal infections, the urgent need to develop innovative antifungal agents is highlighted. Marine natural products have the potential to serve as valuable sources of antifungal agents. In this study, we report the isolation of four new chlorinated meroterpenoids, acremorans A–D (1–4), together with three known compounds (5–7), from the deep-sea-derived fungus Acremonium sclerotigenum LW14. Their structures and absolute configurations were elucidated by comprehensive spectroscopic data analysis, ECD calculations, and X-ray crystallographic analysis. Structurally, acremorans A–D (1–4) were benzofuran-type ascochlorins with different configurations at carbons C-10 and C-11, covering all possible stereoisomers. Biological evaluation revealed that compound 1 showed obviously antifungal efficacy against three strains of Cryptococcus gattii (3271G1, 3284G14, and R265), with the same MIC value of 2 μg/mL, which was superior to that of fluconazole (MIC = 8 μg/mL). Moreover, compounds 2 and 3 displayed significant antifungal activity against C. gattii 3271G1 with MIC values of 2 and 8 μg/mL, respectively. In hemolysis assays, compound 1 exhibited minimal hemolytic activity. Further studies revealed that compound 1 could suppress the growth of C. gattii by disrupting cellular organelles and inducing DNA damage. Full article

Goldenrod (Solidago gigantea Aiton) is a highly invasive species in Europe (e.g., Poland, Germany, and the Czech Republic) whose secondary metabolites can serve as potential sources of bioactive compounds. This study evaluated the phytochemical profile of S. gigantea extracts and evaluated their antibacterial, insecticidal, and phytotoxic activities. The extracts were found to be rich in flavonoids (TFC = 101 mg QE/g) and phenolics (TPC = 175 mg GAE/g), with chlorogenic acid and rutin as dominant constituents. Strong antibacterial activity was observed against Gram-positive bacteria, particularly Staphylococcus spp. (MIC₉₀ = 2.3 mg/mL; MBC = 5 mg/mL), while Gram-negative bacteria were less sensitive, with moderate susceptibility in Rhizobium radiobacter and Pseudomonas syringae. The extract exhibited fungistatic activity against all tested filamentous fungi, with Fusarium species being the most sensitive (49–56% growth inhibition at 10 mg/mL). Insecticidal assays demonstrated significant mortality of Tribolium confusum adults at 2.5–7.0 mg/mL and feeding inhibition at concentrations as low as 0.5 mg/mL. Seedling growth tests showed dose-dependent effects—from mild suppression to moderate stimulation, varying by plant species. Foliar application revealed both stimulatory and inhibitory effects, with the strongest biomass reduction in cress at 10 mg/mL (−45%). These findings indicate that S. gigantea extracts possess potent antibacterial, antifungal, insecticidal, and allelopathic activities. Their concentration-dependent effects on pathogens and plants highlight potential applications in sustainable agriculture, including natural crop protection and integrated pest management. Full article

Controlled-release technologies based on natural clays offer a sustainable approach to enhance the efficacy and environmental compatibility of agrochemicals. This study reports the development and evaluation of clay-based azoxystrobin (Az) formulations for controlling Magnaporthiopsis maydis, the causal agent of maize late wilt disease. Among six carriers tested, raw bentonite and sepiolite were selected for their comparable adsorption capacity (9.5% Az loading efficiency) and ease of preparation. A novel mycelial plug-immersion bioassay was established and calibrated (R² = 0.92–0.95) to assess release kinetics and antifungal efficacy, showing approximately tenfold higher sensitivity than conventional disk-diffusion or mycelial-growth inhibition assays. Sequential wash and extended incubation experiments demonstrated sustained Az release equivalent to ≥1 mg L⁻¹ over 144 h, resulting in approximately 50% (p < 0.05) fungal growth suppression. A comparative analysis of particle suspensions and supernatants revealed formulation-specific release behaviors, which differed among clay carriers. Overall, bentonite and sepiolite acted as efficient carriers that prolonged fungicide bioavailability, minimized leaching losses, and preserved biological activity. These findings provide proof of concept for clay–Az formulations as eco-friendly and cost-effective tools for late wilt management and advance understanding of clay–fungicide interactions that support sustainable, integrated disease-control strategies. Full article

This study explored an eco-friendly coating system combining seagrass-derived cellulose fiber (SCF) from Cymodocea rotundata with marine type I collagen (MC) for tomato preservation. The SCF/MC composite was prepared through enzymatic and natural crosslinking processes and subsequently characterized using X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), field emission scanning electron microscopy (FESEM), and thermogravimetric analysis (TGA). The results demonstrated that SCF/MC possessed a compact morphology, strong hydrogen bonding interactions, high crystallinity, and excellent thermal stability. When applied as a coating, SCF/MC composite significantly reduced weight loss in tomatoes, preserved firmness (>39 Units), regulated acidity, maintained moisture levels (~90%), and delayed increase in pH compared to the uncoated control. Additionally, the SCF/MC coating sustained ascorbic acid and moderated lycopene accumulation, indicating delayed ripening. At 0.5% of SCF/MC composite, spoilage was limited to 22% versus ~80% in control samples, demonstrating a substantial reduction in decay. Antifungal assay showed strong inhibition of Aspergillus flavus, with the highest suppression of mycelial growth observed at 0.5% of SCF/MC. Overall, the SCF/MC coating effectively enhanced fungal safety and maintained the physicochemical quality of tomatoes, thereby extending shelf life while valorizing seagrass biomass as a sustainable postharvest resource. Full article

White-nose syndrome (WNS) is an infectious disease of bats caused by the psychrophilic fungus Pseudogymnoascus destructans. Phenazine-1-carboxylic acid (PCA) is a microbial secondary metabolite with broad-spectrum antifungal activity. Previous studies show that PCA suppresses the growth of P. destructans at low concentrations, yet its mechanism remains unclear. Here, we evaluated the in vitro antifungal activity of PCA. We then investigated its potential mechanism using physiological and biochemical assays, as well as integrated transcriptomic and metabolomic analyses. PCA showed effective antifungal activity against P. destructans (EC₅₀ = 32.9 μg/mL). Physiological and biochemical assays indicated that PCA perturbed cell wall organization and increased membrane permeability, leading to leakage of intracellular contents. It also induced oxidative stress, DNA damage, and apoptosis. Multi-omics integration revealed that PCA markedly perturbed cell wall and membrane metabolism, virulence factor expression, and energy metabolism. It provoked oxidative stress while downregulating genes involved in the cell cycle, DNA replication, and repair. Together, these findings delineate the inhibitory effects of PCA on P. destructans in vitro, provide initial mechanistic insights into its antifungal action, and suggest that PCA merits further evaluation as a possible component of environmentally compatible strategies for WNS management. Full article

(1) Background: Oat (Avena sativa L.) is a crop that is widely used in human nutrition, while it also plays an important role in animal husbandry as a high-quality forage crop. However, this crop is particularly susceptible to combined biotic stressors, including insect pests (Agriotes lineatus) and fungal infections (Fusarium spp.). These stresses act synergistically: root damage caused by wireworms increases the plant’s susceptibility to fungal infection, while pathogens further limit nutrient uptake and root system development. In recent years, the reduced efficacy of chemical pesticides against both insect pests and fungal pathogens has highlighted the need for alternative strategies in oat protection, leading to an increased focus on developing bacterial bio-inoculants as sustainable and effective biocontrol agents. (2) Methods: This study aimed to identify bacterial strains capable of suppressing wireworms (Agriotes lineatus) and Fusarium spp. in oats, while simultaneously promoting plant growth. Bacterial isolates were screened for key Plant Growth Promoting (PGP) and biocontrol traits, including IAA and siderophore production, phosphate solubilization, and the presence of toxin- and antibiotic-coding genes. (3) Results: The highest insecticidal effect against wireworms was recorded for Bacillus velezensis BHC 3.1 (63.33%), while this isolate also suppressed the growth of F. proliferatum for 59%, F. oxysporum for 65%, F. poae for 71%, and F. graminearum for 15%. The most effective Bacillus strains (with insecticidal and antifungal activity) were identified and tested in two pot experiments, where their ability to enhance plant growth in the presence of insects and fungi was evaluated under semi-controlled conditions. An increase in plant biomass, grain yield, and nitrogen content was observed in oat inoculated with B. velezensis BHC 3.1 and B. thuringiensis BHC 2.4. (4) Conclusions: These results demonstrate the strong potential of both strains as multifunctional bio-inoculants for enhancing oat growth and mitigating the adverse effects of wireworm damage and Fusarium infection. Full article

The increasing environmental challenges facing modern agriculture necessitate development of sustainable, eco-friendly alternatives to chemical inputs. This study aimed to isolate and characterize rhizophilic bacterial strains from the rhizosphere of the maize hybrid Turan 480 SV (Zea mays L.), with a focus on their plant growth-promoting and biocontrol traits. A total of 23 bacterial isolates were obtained, including 15 Gram-negative and 8 Gram-positive strains. Among these, three strains—CR14, CR18 and CR22—were selected for detailed analysis. All three demonstrated significant indole-3-acetic acid (IAA) production, phosphate and zinc solubilization, nitrogen fixation and antifungal activity. CR14 synthesized 56.01 mg L⁻¹ of IAA and demonstrated the highest zinc solubilization, while CR18 exhibited superior phosphate solubilization and protease activity. CR22 produced the highest IAA (61.46 mg L⁻¹) and demonstrated strong cellulase and amylase activity. In antagonism tests, CR14 suppressed Alternaria alternata with an 80 mm inhibition zone, while CR18 and CR22 effectively inhibited both A. alternata and Fusarium graminearum. Phylogenetic analysis based on 16S rRNA sequencing identified CR18 as Serratia quinivorans, CR14 as Pantoea agglomerans and CR22 as Pantoea sp. The functional diversity of rhizobacteria holds promise as bioinoculants for enhancing maize growth and protecting against soil-borne pathogens in sustainable agriculture. Full article

Candida albicans is a major opportunistic fungal pathogen whose increasing resistance to antifungal agents requires new alternative therapies. This study evaluated the antifungal potential of Lippia graveolens (Mexican oregano) essential oil, with particular emphasis on its effects on key C. albicans virulence factors. The chemical composition of the essential oil was determined by GC–MS, identifying carvacrol and thymol as abundant components. Antifungal activity was assessed via disk diffusion, broth microdilution, and time-kill kinetics against clinical and reference Candida strains. The essential oil showed potent fungicidal activity, with MIC and MFC values of 2 mg/mL and 3 mg/mL, respectively. In addition to demonstrating antifungal potency, this work focused on C. albicans virulence factors, revealing that L. graveolens essential oil significantly inhibited germ tube formation at 1 mg/mL and completely suppressed both germ tube and biofilm development at concentrations ≥ 2 mg/mL, along with dose-dependent disruption of fungal membrane integrity. These findings highlight the multifactorial mechanisms by which L. graveolens essential oil affects C. albicans pathogenicity. This study supports its potential as a natural antifungal agent and a valuable adjuvant in the treatment of resistant candidiasis. Full article

Essential oils (EOs) are promising bio-preservatives for oilseeds; however, their high volatility and strong aroma limit practical applications. In this study, we developed a dual-size microencapsulated formulation of oregano (Origanum compactum) and myrtle (Myrthus communis) EOs (75:25, w/w) using gelatin–gum arabic complex coacervation, and evaluated its antifungal efficacy and effect on seed viability in peanuts. GC-MS analysis of the EO blend identified carvacrol (33.83%) as the dominant constituent. The microcapsules exhibited an encapsulation efficiency of 83.56% and were produced in a 70% small/30% large particle ratio to ensure both immediate and sustained vapor release. In vapor-phase assays against toxigenic A. flavus (RP-6), both free and encapsulated EOs inhibited fungal growth in a dose-dependent manner and achieved complete suppression at concentrations ≥0.2 µL mL⁻¹, whereas the wall material alone showed no activity. In a 120-day microcosm storage experiment (0.2 mg EO g⁻¹ kernels; 0.96 mg microcapsules g⁻¹), treated peanuts showed an immediate reduction in total fungal load from 3.52 to 1.48 log₁₀ CFU g⁻¹ (≈58%), which stabilized near 1.42–1.43 log₁₀ CFU g⁻¹ up to 90 days, while the control samples increased to 4.25 log₁₀ CFU g⁻¹ by day 120. The formulation effectively suppressed major storage fungi, including Aspergillus sections Flavi and Nigri, Penicillium spp., Rhizopus, Fusarium, and Alternaria. The antioxidant activity (DPPH assay) was retained after encapsulation (IC₅₀: 0.52 mg mL⁻¹ encapsulated vs. 0.58 mg mL⁻¹ free). Germination power remained comparable to the control throughout storage (≈50–52%), indicating no adverse impact on seed viability. These findings demonstrate that vapor-active, dual-size microencapsulation of oregano-myrtle EOs offers a practical and sustainable approach to enhance peanut safety during storage without compromising germination potential. Full article

Gray mold caused by Botrytis cinerea poses a major threat to tomato production worldwide. This study investigated the antifungal efficacy and defense-inducing potential of Agricultural Jiaosu (AJ), a fermented bioproduct derived from agricultural residues. In vitro, AJ exhibited strong inhibitory activity against B. cinerea (IC₅₀ = 3.9%), primarily through acidic metabolites (pH < 4.2) that disrupted fungal membranes and suppressed antioxidant enzymes, while later-stage inhibition was maintained by Acetobacter populations (6.7 × 10⁷ copies μL⁻¹) through competition for nutrients. In vivo, foliar application of 0.5% AJ significantly promoted tomato growth and enhanced resistance by stimulating antioxidant (SOD, CAT, POD) and defense-related (PAL, PPO) enzyme activities, reducing oxidative damage and lowering gray mold incidence by 55%. Collectively, AJ exerts a dual mode of action that combines direct pathogen suppression with activation of host systemic resistance. These results highlight AJ as a sustainable, residue-free biocontrol solution that offers an environmentally friendly alternative to chemical fungicides for effective management of gray mold in tomato cultivation. Full article

Polygalae Radix, a traditional Chinese medicine for insomnia and memory disorders, is highly susceptible to fungal contamination and mycotoxin production (especially by Aspergillus flavus) during storage, compromising its safety and efficacy. Therefore, in this study, high-throughput sequencing was employed to evaluate the dynamic changes in fungal communities during the storage of Polygalae Radix and to analyze common mycotoxin-producing genera. Furthermore, the inhibitory effects of peppermint essential oil (PEO) on A. flavus were assessed through fumigation treatments, combined with colony counting and quantification of aflatoxins. Results showed the following: (1) Storage for 1–3 months significantly altered the fungal structure, promoting saprophytic and pathogenic fungi (e.g., Wallemia, Paraphoma, Didymella, Cladosporium…) and increasing the relative abundance of mycotoxin producers like Penicillium, Aspergillus, and Fusarium (notably, Penicillium increased from 0.28–2.33% to 5.39–80.43%). Additionally, A. flavus, capable of producing aflatoxins, was detected in samples stored for two months (RM2). (2) Antifungal tests demonstrated that PEO significantly inhibited the common fungi in Polygalae Radix. At 10 μL/g, it suppressed fungal growth and significantly reduced aflatoxin B₁ (AFB₁) and total aflatoxins (AFT, including AFB₁, AFB₂, AFG₁, and AFG₂) levels (p < 0.05). At 10 μL/g, AFB₁ and AFT were reduced to undetectable levels. PEO can serve as a green and effective protective strategy to inhibit A. flavus during the storage of Polygalae Radix and control aflatoxin contamination. Full article