TL;DR
The identification of a potential novel species capable of producing extracellular secondary metabolites to control anthracnose-causing fungi that infect postharvest fruits is shown.
: Clove ( Syzygium aromaticum ), a member of the Myrtaceae family, is widely distributed throughout tropical regions from Indonesia to China. This research aimed to investigate the antifungal effects and mechanisms of clove essential oil (CEO) against Fusarium oxysporum , the causal agent of root rot disease in Pseudostellaria heterophylla and other crops. The inhibitory effects of CEO on mycelial growth, spore germination and ergosterol biosynthesis of F. oxysporum were assessed through in vitro assays. The mechanism was initially investigated by analyzing the primary components of CEO using gas chromatography-mass spectrometry (GC-MS) and performing molecular docking studies with the target enzyme. Results showed that CEO inhibited mycelial radial growth in a dose-dependent manner, with inhibition rates ranging from 16.61% to 100%. The median effective concentration (EC 50 ) value was determined to be 131.7 µ L/L (R 2 = 0.985). Spore germination decreased significantly by 61.6% at 300 µ L/L ( p < 0.05), resulting in shortened germ tubes and noticeable morphological changes. CEO inhibited ergosterol biosynthesis in a concentration-dependent manner, disrupting membrane integrity. The inhibition rate can reach 34.6% at 150 µ L/L ( p < 0.05). GC-MS analysis identified 24 compounds, with phenylpropanoids representing 92.44% of compounds. Within this category, eugenol and eugenyl acetate were the predominant components, representing 72.51% and 19.66%, respectively. The molecular docking results showed that eugenyl acetate exhibits a strong binding affinity for ERG3 and CYP51, with binding free energies of − 6.615 and − 6.336 kcal/mol, respectively. This research identifies eugenyl acetate as a key component contributing to the antifungal effect through molecular docking, and reveals a dual-action antifungal mechanism of CEO against F. oxysporum . These findings suggest that CEO has potential natural antifungal agent for controlling soil-borne diseases by disrupting membranes through ergosterol inhibition.
BACKGROUND Soybean anthracnose caused by Colletotrichum truncatum is a destructive disease threatening soybean production. Increasing fungicide resistance and concerns over chemical residues highlight the need for new antifungal agents with distinct bioactive scaffolds. This study aims to identify the antifungal metabolite produced by Streptomyces paludis 13-3 and evaluate its potential for soybean anthracnose management RESULTS: Bioassay-guided fractionation of the fermented extract of S. paludis 13-3 led to the isolation of oligomycin A, characterized via nuclear magnetic resonance spectroscopy and high-resolution electrospray ionization mass spectrometry. It exhibited half-maximal effective concentration (EC50) values of 0.0173 μg mL-1 and 0.0811 μg mL-1 against mycelial growth and conidial germination of C. truncatum, respectively. Its antifungal potency was approximately 58 times more potent than difenoconazole. At a concentration of 1 μg mL-1, oligomycin A achieved 85.85% control efficacy against soybean anthracnose on detached seedlings without inducing phytotoxicity, and inhibited eight tested phytopathogens by 61.69-83.39% at 0.1 μg mL-1. Fluorescence staining and scanning electron microscopy observations indicated intracellular reactive oxygen species (ROS) accumulation and significant structural damage in C. truncatum treated with oligomycin A. CONCLUSION This study provides the first evidence that oligomycin A exhibits strong antifungal activity against C. truncatum and effectively suppresses soybean anthracnose development in detached seedlings. These findings expand the known antifungal spectrum of oligomycin A and highlight its value as a natural lead compound for the development of antifungal agents against soybean anthracnose. © 2026 Society of Chemical Industry.
Panama wilt is a devastating disease caused by the soilborne fungus Fusarium oxysporum f. sp. cubense (Foc) and poses a serious threat to the global banana industry, including the expanding plantations of Jharkhand, India. In this study, the antifungal potential of onion (Allium cepa L.) bulb extract against Foc was evaluated in a multifaceted way, including field surveys,in vitroassays, LC-MS metabolomics and molecular docking. Field surveys in East and West Singhbhum districts showed disease incidence rates ranging from 15.7% to 53.4%. In vitro evaluation using the poisoned-food technique revealed concentration-dependent inhibition of mycelial growth, with the highest reduction of 62.65% observed at a 20% extract concentration. The greenhouse study showed that the 20% extract concentration was the most effective. It had the lowest wilt incidence (25%) and the highest disease reduction (73.68%) compared to the untreated control (95%). Ethanolic onion extract was profiled by LC-MS, resulting in the identification of a wide variety of bioactive compounds, mainly alkaloids and isoquinoline derivatives, with 2-methoxy-5-dehydro-scoulerine as the most abundant metabolite. We conducted molecular docking studies on the SGE1 protein, a key regulator of Foc pathogenicity. Our results indicated that several identified compounds exhibited high binding affinities, particularly dihydronitidine (-8.1 kcal/mol) and fagaronine (-7.4 kcal/mol), which formed stable interactions within the enzyme's catalytic pocket via hydrogen bonding and aromatic Pi interactions. These results suggest that onion bio-actives can effectively suppress Foc virulence by targeting key pathogenicity factors. Our study demonstrates the efficacy of onion bulb extract as a botanical alternative for managing Panama wilt, offering a sustainable solution for smallholder farmers.
Endophytic fungi inhabiting medicinal plants represent a largely untapped reservoir of biologically active compounds with potential therapeutic value. This study reports the isolation of endophytic fungi associated with the medicinal plant Munronia pinnata , followed by morphological and molecular characterization, secondary metabolite extraction, evaluation of anti‐microbial and anti‐oxidant properties, and metabolite profiling by GC–MS. A total of 18 endophytic fungi were isolated, including Colletotrichum , Aspergillus , Diaporthe , and Fusarium . Colletotrichum plurivorum and Aspergillus aculeatinus were identified by multi‐locus phylogeny and exhibited broad‐spectrum anti‐microbial activity, with zones of inhibition ranging from 17 ± 1 to 42 ± 2 mm in the agar plug diffusion assay against Staphylococcus aureus (ATCC 25923), Bacillus cereus (ATCC 11778), and Escherichia coli (ATCC 25922). The ethyl acetate extracts of C. plurivorum and A. aculeatinus showed zones of inhibition of 15 ± 1 to 23 ± 1 mm in the agar disc diffusion assay, with minimum inhibitory concentrations ranging from 31.5 to 125 µg/mL against the same set of pathogens. The ethyl acetate extract of A. aculeatinus exhibited potent anti‐oxidant activity in both the ferric reducing anti‐oxidant power and 2,2′‐azino‐bis(3‐ethylbenzothiazoline‐6‐sulfonic acid) radical cation scavenging (IC 50 value of 15.6 ± 0.3 µg/mL) assays. GC–MS analysis of the ethyl acetate extract revealed 12 compounds from C. plurivorum and 16 from A. aculeatinus , likely contributing to the observed bioactivities. These compounds include fatty acids, phenolics, terpenoids, anthraquinones, and a rare naphthalene derivative. The results highlight the potential of endophytes as untapped reservoirs of novel therapeutic agents for the development of innovative and sustainable products in the pharmaceutical industry.
Watermelon (Citrullus lanatus) is an economically important fruit crop susceptible to post harvest fungal diseases. Hyptis suaveolens L. (Bush Mint) is a medicinal aromatic shrub renowned for its diverse bioactive secondary metabolites, and the present study investigated the phytochemical composition and antifungal potential of its aqueous and ethanolic leaf extracts against Aspergillus flavus, Aspergillus niger, Fusarium oxysporum, and Rhizopus oligosporus — major causative agents of watermelon fruit rot. Extraction was performed by the cold maceration method of Harborne (1998) with slight modifications; qualitative and quantitative phytochemical analyses were conducted using standard procedures; Gas Chromatography–Mass Spectrometry (GC-MS) was employed to characterize bioactive components; antifungal activity was evaluated by the agar well diffusion method (50–400 mg/mL); and the Minimum Inhibitory Concentration (MIC) was determined by broth microdilution in Sabouraud Dextrose Broth across serial two-fold dilutions of 6.25–400 mg/mL. Phytochemical screening confirmed alkaloids, flavonoids, saponins, tannins, terpenoids, and phenols, with the ethanolic extract showing significantly higher concentrations; GC-MS identified 45 compounds, with resorcinol (15.05%), squalene (13.72%), d,α-tocopherol (12.13%), 2,4-di-tert-butylphenol (5.49%), and phytol isomer (4.17%) as the most abundant; the ethanolic extract exhibited superior antifungal efficacy with larger inhibition zones, particularly against A. flavus, followed by A. niger, F. oxysporum, and R. oligosporus, with the lowest MIC (12.5 mg/mL) recorded against A. flavus, while the aqueous extract required up to 50 mg/mL. These findings underscore the significant antifungal potential of H. suaveolens and support its application as a natural botanical fungicide for managing post-harvest fungal diseases in watermelon fruits.
Damping-off disease caused by Rhizoctonia solani is a devastating soilborne disease that poses a serious threat to sustainable ginseng (Panax ginseng) production. In an effort to develop environmentally friendly control alternatives, we investigated the volatile constituents of Asarum heterotropoides essential oil using GC-MS in 2023 and identified methyleugenol as the predominant bioactive component, accounting for 21.32% of the total volatile fraction. Mycelial growth rate assays demonstrated that methyleugenol exerted pronounced antifungal activity against R. solani, with EC50 and EC90 values of 60 mg/L and 800 mg/L, respectively. Treatment at 0.1 mg/mL resulted in 51% growth inhibition after 4 days of incubation. To elucidate the underlying mechanisms of action, R. solani mycelia exposed to 0.1 mg/mL methyleugenol were harvested at 4 and 6 days post-treatment for integrated transcriptomic and untargeted metabolomic profiling. Transcriptome analysis revealed 1444 and 1157 significantly downregulated genes at 4 and 6 days, respectively, with 836 genes consistently repressed at both time points. GO and KEGG enrichment analyses indicated that these persistently suppressed genes were predominantly associated with protein processing in the endoplasmic reticulum, protein export, tyrosine metabolism, and peroxisome biogenesis. Metabolomic profiling identified 95 differentially accumulated metabolites that were commonly reduced across both time points, with KEGG pathway enrichment highlighting significant suppression of starch and sucrose metabolism and galactose metabolism pathways central to carbon source utilization. Integrative transcriptome–metabolome correlation analysis further uncovered three key transcription factors (gene-RDB_LOCUS74145, gene-RDB_LOCUS26344, and gene-RDB_LOCUS52181) implicated in the regulation of carbohydrate metabolism and tricarboxylic acid cycle-related metabolite production. Collectively, our findings indicate that methyleugenol suppresses R. solani growth through a multi-target mechanism involving impairment of carbon source metabolism, disruption of protein processing and secretion, and attenuation of cellular energy supply. These results provide a mechanistic foundation for the development of botanical fungicide-based strategies for the green management of ginseng damping-off disease.
