Search Results (205)

Phytopathogenic fungi that affect postharvest are a serious problem for agriculture, so this research explores the antifungal potential of three different “rosemary” species growing in Chile through in vitro and in silico assays. The analysis of essential oils (GC/MS) reveals the dominant constituents of Salvia rosmarinus (camphor: 66.96%), Baccharis linearis (lachnophyllum ester: 88.62%) and Fabiana imbricata (an oxygenated sesquiterpene: 43.66%) and shows profiles that differ from chemotypes of the same species from other areas of the world. B. linearis oil was shown to be a versatile antifungal substance, inhibiting Botrytis cinerea and Monilinia fructicola at moderate concentrations; F. imbricata oil stood out as a major inhibitor of mycelial growth of the same isolate of M. fructicola used to test B. linearis oil (EC₅₀ of 15.86 + 0.67 µg/mL) and completely inhibited of its conidial germination. In silico assays confirmed the complexity of interactions of F. imbricata sequiterpenoids with catalytic sites of succinate dehydrogenase and catalase 2, key enzymes in mycelial growth and in maintaining redox homeostasis in the early development of M. fructicola, respectively. The results of this research make F. imbricata a good candidate for the development of a formulation applicable in vivo as an eco-friendly post-harvest antifungal agent. Full article

Packaging is essential for protecting, distributing, and trading fresh fruit. Antimicrobial packaging, which incorporates natural or synthetic bioactive compounds, can inhibit microbial growth, extend shelf life, and reduce reliance on synthetic fungicides. This study aimed to evaluate the effect of allyl isothiocyanate (AITC), released from black mustard seeds, on the quality and fungal development of ‘Burlat’ sweet cherries during postharvest storage under modified atmosphere. The in vitro and in vivo antimicrobial activity of AITC, released from different amounts of mustard seeds in an ‘Inbox’ system, was compared with fludioxonil, a synthetic fungicide authorised for postharvest use on stone fruits in the European Union. The impact of these treatments on weight loss, headspace gas composition, fruit decay, physicochemical and microbiological quality was also analysed. Results showed that AITC inhibited the in vitro growth of Cladosporium cladosporioides, Monilinia laxa and Penicilium expansum, and significantly reduced Alternaria alternata, Botrytis cinerea, and Geotrichum candidum after 96 h at 25 °C and 99% RH. Treatment with 100 mg of mustard seeds achieved rot control comparable to fludioxonil, while maintaining higher firmness and delaying skin darkening after 28 days. Overall, natural AITC from mustard seeds appears to be a promising alternative for preserving sweet cherry quality. Full article

Botrytis cinerea Pers., the causal agent of grey mould, causes major economic losses in viticulture by reducing grape and wine quality and yield. Antagonistic yeasts that release bioactive volatile organic compounds (VOCs) represent a sustainable alternative to synthetic fungicides. Here, VOCs produced by Pichia guilliermondii strain ZIM624 were identified and assessed for antifungal activity against B. cinerea. 65 VOCs—including higher alcohols, volatile phenols, esters, and terpenes—were detected using two newly developed and validated analytical methods combining automated headspace solid-phase microextraction with gas chromatography–mass spectrometry. A total of 13 VOCs were selected for the bioassays. Fumigation assays demonstrated that terpenes (citronellol, geraniol, nerol, α-terpineol, and linalool) were the most effective inhibitors of B. cinerea mycelial growth (EC₅₀ = 6.3–33.9 μL/L). Strong inhibition was also observed for 4-vinylphenol and isoamyl acetate. In vivo assays confirmed that exposing infected grape berries to P. guilliermondii VOCs significantly reduced grey mould incidence. These results highlight the potential of P. guilliermondii ZIM624 volatiles as natural biofumigants for the eco-friendly management of B. cinerea in grapes. Future research should focus on optimising VOC production, evaluating efficacy under field conditions, and developing formulations for practical application in vineyards and post-harvest storage. Additionally, investigating potential synergistic effects of VOC combinations could lead to more effective biocontrol strategies. Full article

This study aimed to select Metschnikowia pulcherrima strains with antimicrobial potential and high biomass content, optimize their cultivation conditions, evaluate growth characteristics at different scales, and assess antimicrobial activity on apple plants (Malus domestica cv. Golden Delicious) infected with phytopathogens. Of the nine tested strains, M. pulcherrima D2 was selected for its strong inhibitory activity against all tested phytopathogenic molds: Venturia inaequalis, Botrytis cinerea, Phoma exigua, Colletotrichum coccodes, Monilia laxa, Alternaria alternata, Alternaria tenuissima, Fusarium sambucinum, and Fusarium oxysporum, both in vitro on laboratory media (inhibition zones from 13.5 to 35.0 mm) and in vivo on stems, leaves, flowers, and fruits of apple. Morphological observations of treated plants showed the complete absence or significant delays of disease symptoms for up to 10 days. Disease symptoms for several pathogens (V. inaequalis, A. alternata, A. tenuissima, B. cinerea, F. sambucinum) remained reduced by ≥50% for up to 31 days post-treatment compared to the untreated control. Optimal cultivation conditions for M. pulcherrima D2 were established: a complex medium containing yeast extract (5.0 g/L), soy peptone (5.0 g/L), and glucose (2.6 g/L), at pH 5 and 25 °C, with shaking at 180 rpm, resulted in high biomass contents (10⁷–10⁸ CFU/mL). Scale-up in 5 L bioreactors confirmed efficient biomass production (10⁸ CFU/mL and from 3.1 to 3.9 g/L of dry biomass). These findings highlight the strong biotechnological potential of M. pulcherrima D2 for the development of a biocontrol agent to protect apple fruits and trees against fungal phytopathogens. 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

Microbial spoilage of nutrient-rich strawberries leads to considerable food waste and economic losses. Plant-derived phenolic compounds, including resveratrol (RES), epigallocatechin gallate (EGCG), and tea polyphenols (TP), have gained attention for their multi-target antimicrobial efficacy and potential applications in fruit preservation. This study evaluated the individual and combined effects of these three compounds on strawberries infected with Escherichia coli (E. coli) and Botrytis cinerea (B. cinerea). The minimum inhibitory concentration (MIC) values for RES (analytical grade, ≥99% purity) and EGCG (analytical grade, ≥98% purity) against E. coli were 1.56 g/L and 25 g/L, with an additive effect against E. coli growth (FICI = 0.625). 5 g/L TP (analytical grade, ≥98% purity) completely inhibited the mycelial growth of B. cinerea. The in vivo application of RES and EGCG significantly reduced spoilage and improved texture, color, weight retention, and flavor quality in strawberries infected by E. coli individually or in combination. Similarly, the combined use of TP and chitosan saved the quality of strawberries infected by B. cinerea compared to single treatments. This study provided new effective and eco-friendly strategies for the preservation of strawberries. Full article

Endophytic fungi were isolated from ginger (Zingiber officinale) tubers and identified through molecular characterization of ITS and 28S rRNA regions. Nine species were obtained, belonging to the genera Aspergillus, Penicillium, Plectosphaerella, and Pseudogymnoascus. Several isolates, particularly Penicillium melinii, Aspergillus ustus, and Plectosphaerella cucumerina, exhibited strong antagonistic activity against Botrytis cinerea (up to 98.6% growth inhibition), while moderate effects were observed against Colletotrichum acutatum, Staphylococcus aureus and Klebsiella pneumoniae. All isolates produced at least one extracellular enzyme, with lipolytic and cellulolytic enzymes being the most frequently observed, and showed measurable antioxidant activity (EC₅₀ values ranging from 21.7 to 673.6 µg/mL). P. melinii and P. cucumerina demonstrated the highest radical scavenging capacities. These findings reveal the multifunctional potential of ginger-associated endophytic fungi as sustainable sources of bioactive compounds, with promising applications in biocontrol, food preservation, and industrial biotechnology. Full article

Botrytis cinerea, a necrotrophic fungal pathogen responsible for gray mold, poses a severe threat to over 1400 plant species, causing significant pre- and postharvest losses worldwide. RNA interference (RNAi)-based strategies, particularly spray-induced gene silencing (SIGS), have emerged as environmentally friendly alternatives to chemical fungicides. However, the application of naked double-stranded RNA (dsRNA) suffers from poor stability and low cellular uptake. In this study, we engineered a self-assembling triangular RNA nanoparticle, termed Bc-triangle, targeting four virulence genes of B. cinerea—BcDCL1, BcPPI10, BcNMT1 and BcBAC. The nanostructure was designed using RNA origami principles and produced in Escherichia coli. Functional assays demonstrated that Bc-triangle significantly inhibited conidial germination and mycelial growth in vitro, and markedly reduced disease severity in plants. Compared with linear dsRNA, Bc-triangle showed superior persistence and efficacy, with lesion area reduction sustained up to 10 days post-spraying. qRT-PCR analysis revealed substantial downregulation of the target genes, especially BcNMT1, indicating enhanced RNAi activation. These findings establish RNA nanotechnology as a powerful platform for transgene-free, programmable, and sustainable control of fungal pathogens in crop production. Full article

Metal-free aminobenzoic acid-derived Schiff bases are attractive antimicrobial leads because their azomethine (–C=N–) functionality enables tunable electronic properties and target engagement. We investigated whether halogenation on the phenolic ring would modulate the redox behavior and enhance antibacterial potency, and hypothesized that heavier halogens would favorably tune physicochemical and electronic descriptors. We synthesized three derivatives (SB-3/Cl, SB-4/Br, and SB-5/I) and confirmed their structures using FTIR, ¹H- and ¹³C-NMR, UV-Vis, and HRMS. For SB-5, single-crystal X-ray diffraction and Hirshfeld analysis verified the intramolecular O–H⋯N hydrogen bond and key packing contacts. Cyclic voltammetry revealed an irreversible oxidation (aminobenzoic ring) and, for the halogenated series, a reversible reduction associated with the imine; peak positions and reversibility trends are consistent with halogen electronic effects and DFT-based MEP/LHS descriptors. Antimicrobial testing showed that SB-5 was selectively potent against Gram-positive aerobes, with low-to-mid micromolar MICs across the panel. Among anaerobes, activity was more substantial: Clostridioides difficile was inhibited at 0.1 µM, and SB-3/SB-5 reduced its sporulation at sub-MICs, while Blautia coccoides was highly susceptible (MIC 0.01 µM). No activity was detected against Gram-negative bacteria at the tested concentrations. In the fungal assay, Botrytis cinerea displayed only a transient fungistatic response without complete growth inhibition. In mammalian cells (HeLa), the compounds displayed clear concentration-dependent behavior. Overall, halogenation, particularly iodination, emerges as a powerful tool to couple redox tuning with selective Gram-positive activity and a favorable cellular tolerance window, nominating SB-5 as a promising scaffold for further antimicrobial optimization. Full article

Ten phyllospheric yeast strains were studied for their potential as biocontrol agents against fruit spoilage mould. The efficacy of these yeasts against Botrytis cinerea and Fusarium fujikuroi was assessed using dual-culture, mouth-to-mouth, radial growth inhibition and post-harvest fruit assays. Additionally, their capacity for producing hydrolytic enzymes was examined. Results from the ten yeasts revealed dual culture antagonism ranging from 41% to 63% against B. cinerea and 23% to 48% against F. fujikuroi, along with radial inhibition ranging from 70% to 100% and 47% to 100%, respectively. Additionally, in vitro inhibition through the production of volatile organic compounds (VOCs) varied from 2% to 46% against B. cinerea and 6% to 64% against F. fujikuroi. Overall, Aureobasidium melanogenum J7, Suhomyces pyralidae Y1117, Dekkera anomala V38, and Rhodotorula diarenensis J43 emerged as the best-performing biocontrol yeasts. Volatile organic compounds produced by the four yeasts were also identified and included in fruit bioassays using pears and tomatoes. Various VOCs, including 1-butanol, 3-methylbutanol, and butyric acid, were linked to the antagonistic properties of the selected yeasts. Lastly, the four chosen yeast strains significantly mitigated post-harvest spoilage caused by B. cinerea and F. fujikuroi in pear and tomato fruits, with D. anomala V38 exhibiting the greatest inhibitory activity. These findings underscore a potential sustainable and efficient approach to reducing mould-induced post-harvest spoilage while reducing reliance on synthetic fungicides. Full article

Essential oils (EOs) from the leaves of Origanum vulgare subsp. virens (Hoffmanns. & Link) Bonnier & Layens, representing three chemotypes—thymol-rich, carvacrol-rich, and a mixed thymol–carvacrol type—were chemically characterized and comparatively assessed for their antifungal, insecticidal, and enzyme-inhibitory activities. This integrated approach provides a comparative assessment of all three chemotypes across multiple biological models, including phytopathogenic fungi, insect bioassays, and key enzyme targets. All EOs displayed antifungal activity for the tested phytopathogenic fungi (Alternaria alternata, Botrytis cinerea, and Fusarium oxysporum) at concentrations above 0.5 mg/mL, with the thymol-rich chemotype showing the highest activity. The minimum inhibition concentration for Oidium farinosum conidial growth was determined and found to be similar for thymol and carvacrol chemotypes and lower for the terpene mixture. Insect control activity was evaluated by an antifeeding assay, where carvacrol and especially thymol chemotypes can be classified as feeding deterrents. EOs and standards revealed a weak toxicity against Ceratitis capitata, with less than 20% mortality at a concentration of 50 mg/mL, and both chemotypes were found to be ineffective in preventing egg deposition. The acetylcholinesterase (AChE) inhibition assay revealed that carvacrol had the greatest inhibitory effect on AChE, followed by EOs, and, finally, thymol. Regarding the α- and β-glucosidase (α- and β-GLU) inhibitory assays, thymol had the strongest inhibitory effect on α-GLU, while plant β-GLU was not inhibited by the standards or OEs. Full article

Gray mold (Botrytis cinerea) and brown rot (Monilinia fructicola) are devastating diseases in stone fruit production. In this work, a series of 3-acyl-6-bromoindoles, including six new compounds, were synthesized via green and efficient microwave-assisted methodology to evaluate their antifungal potential. Bioassays revealed a remarkable duality in the compounds’ mechanism of action. The starting material, 6-bromoindole (I), proved to be a highly potent inhibitor of mycelial growth, with a remarkable EC₅₀ of 11.62 µg/mL against B. cinerea and 18.84 µg/mL against M. fructicola, surpassing BC-1000^® and Captan^® and comparable to Mystic^®. Conversely, compound I was ineffective at inhibiting conidial germination. In stark contrast, the simple acetylated derivative 3-acetyl-6-bromoindole (II) emerged as a formidable inhibitor of spore germination, achieving 100% inhibition for B. cinerea and 96% for M. fructicola, outperforming several controls. This suggests that, while compound I is effective against established infections, compound II acts as a powerful preventative agent against initial spore-based propagation. The antifungal activity of the compounds directly correlates with their ability to bind to the enzymes SDH and MfCat2, the latter being the main mechanism of action. These findings highlight the potential of developing specialized fungicides from the 6-bromoindole scaffold, targeting different stages of fungal development. Full article

Molecules containing indole cores are of interest due to their multiple biological applications and seem to be an alternative to face contemporary challenges in agriculture, especially the control of phytopathogens that affect fruit quality. In this research, starting from 5-bromoindole (A), eleven 3-acyl-5-bromoindole derivatives with linear (B–G) and aromatic (H–L) substitutions were obtained through microwave-assisted synthesis. The antifungal capacity of indole, 5-bromoindole (A) and their derivatives (B–L) were determined by in vitro assays on Monilinia fructicola and Botrytis cinerea, and a molecular docking was performed on mitochondrial complex II, succinate dehydrogenase (SDH). The results indicate that compounds A, B, G, and L were able to inhibit the growth of M. fructicola, while only A and J showed activity against B. cinerea. The acylation of A improved their ability to inhibit the germination of conidia on both pathogens. Compounds A, B and G are the most promising candidates for future research due to their inhibition on M. fructicola and/or B. cinerea and demonstrate favorable binding energies with SDH. Full article

The most common reason for a decrease in the quantity and quality of produced crops is microbial diseases. The aims of this study were to evaluate the antagonistic activity of Streptomyces sp. CACIS-1.16CA against plant pathogenic fungi and to assess its bioactive metabolites to inhibit fungal conidial germination. Antagonistic evaluations of fungal phytopathogens were performed using dual and multiple confrontation assays. Additionally, the inhibitory effect of the bioactive extract (BE) containing secondary metabolites produced by the CACIS-1.16CA strain on the germination of conidia from some fungi was tested. The results indicate that Streptomyces sp. CACIS-16CA inhibited the growth of all tested pathogens (16 strains) with percentages of inhibition (PIs) ranging from 43.3% to 72%, while S. lydicus inhibited 13 of the 16 fungi, with PI values from 35.6% to 68.5%. Moreover, CACIS-1.16CA exerted superior PI values (significant differences at p < 0.05) than S. lydicus against the damping-off fungi consortia with Phytophthora capsici, Fusarium oxysporum, and Rhizoctonia solani. Otherwise, an inhibitory effect was observed on the germination of conidial cells due to the interaction with the BE in Alternaria sp., Botrytis cinerea, and Colletotrichum spp. In conclusion, Streptomyces sp. CACIS-1.16CA may serve as an effective and natural alternative for managing several fungal plant diseases. Full article

One of the important traits of many plant growth-promoting rhizobacteria (PGPR) is the biocontrol of phytopathogens. Some PGPR metabolize phytohormone abscisic acid (ABA); however, the role of this trait in plant–microbe interactions is scarcely understood. Phytopathogenic fungi produce ABA and use this property as a negative regulator of plant resistance. Therefore, interactions between ABA-producing necrotrophic phytopathogen Botrytis sp. BA3 with ABA-metabolizing rhizobacterium Rhodococcus sp. P1Y were studied in a batch culture and in gnotobiotic hydroponics with sunflower seedlings. Rhizobacterium P1Y possessed no antifungal activity against BA3 and metabolized ABA, which was synthesized by BA3 in vitro and in associations with sunflower plants infected with this fungus. Inoculation with BA3 and the application of exogenous ABA increased the root ABA concentration and inhibited root and shoot growth, suggesting the involvement of this phytohormone in the pathogenesis process. Strain P1Y eliminated negative effects of BA3 and exogenous ABA on root ABA concentration and plant growth. Both microorganisms significantly modulated the hormonal status of plants, affecting indole-3-acetic, salicylic, jasmonic and gibberellic acids, as well as cytokinins concentrations in sunflower roots and/or shoots. The hormonal effects were complex and could be due to the production of phytohormones by microorganisms, changes in ABA concentrations and multiple levels of crosstalk in hormone networks regulating plant defense. The results suggest the counteraction of rhizobacteria to ABA-producing phytopathogenic fungi through the metabolism of fungal ABA. This expands our understanding of the mechanisms related to the biocontrol of phytopathogens by PGPR. Full article