Search Results (374)

Sheath blight (ShB), caused by the necrotrophic fungus Rhizoctonia solani (R. solani), poses severe threats to global rice production. Developing a resistant variety with an ShB-resistance gene is one of most efficient and economical approaches to control the disease. Here, we identified a highly conserved chloroplast-localized stem-loop-binding protein encoding gene (OsCSP41b), which shows great potential in developing an ShB-resistant variety. OsCSP41b-knockout mutants exhibit chlorotic leaves and increased ShB susceptibility, whereas OsCSP41b-overexpressing lines (CSP41b-OE) display significantly enhanced resistance to R. solani, as well as to drought, and salinity stresses. Notably, CSP41b-OE lines present a completely comparable grain yield to the wild type (WT). Transcriptomic analyses reveal that chloroplast transcripts and photosynthesis-associated genes maintain observably elevated stability in CSP41b-OE plants versus WT plants following R. solani infection, which probably accounts for the enhanced ShB resistance of CSP41b-OE. Our findings nominate the OsCSP41b gene as a promising molecular target for developing a rice variety with stronger resistance to both R. solani and multi-abiotic stresses. Full article

The potential of Trichoderma fungi as biocontrol agents has not yet been fully explored, as there is a large repertoire of inter- and intra-species variation in their phytopathogenic antagonistic effects due to different adaptations of individual Trichoderma strains. In the present study, we investigated the biocontrol efficacy of eight native isolates of Trichoderma spp. against the soilborne phytopathogens Sclerotinia sclerotiorum and Rhizoctonia solani and a representative of the Mucoromycota, Phycomyces blakesleeanus. An in vitro dual culture test showed a complete (100%) inhibition of S. sclerotiorum and P. blakesleeanus by each tested Trichoderma strain and a high (80–100%) inhibition of R. solani. The crude chloroform extracts, whose peptide contents were confirmed by thin-layer chromatography, caused a concentration-dependent reduction in the growth of the target fungi, with inhibition comparable to the effect of the peptaibol standard alamethicin. Despite the differences between fungi from the phyla Basidiomycota, Ascomycota, and Mucoromycota, their inhibition by alamethicin followed the same dose–response dependence. The growth inhibition of P. blakesleeanus induced by Trichoderma extracts was characterized by a significantly increased activity of antioxidative defense enzymes. Both variants of biocontrol agents, the native strains of Trichoderma spp. and their extracts, are efficient in controlling fungal growth and should be considered for the development of new potent bioformulations applicable in agriculture. Full article

Soilborne diseases cause losses of 45–70% in faba bean in Ethiopia. Studies were undertaken to define soilborne pathogens and their complexes in Ethiopia. First, the severity of root rot was assessed in 150 field sites across seven Ethiopian regions. Soil samples were collected, and the DNA of 29 pests and pathogens was quantified using a commercial quantitative PCR (qPCR) soil testing service. There was a very high incidence rate of Macrophomina phaseolina, as well as Pythium clades F and I. The other detected species in order of incidence included Fusarium redolens, Rhizoctonia solani, Aphanomyces euteiches, Phytophthora megasperma, Sclerotinia sclerotiorum and S. minor, and Verticillium dahliae, as well as low levels of Thielaviopsis basicola. Five anastomosis groups (AG) of R. solani, namely AG2.1, AG2.2, AG3, AG4, and AG5, were detected, of which AG2.2 and AG4 were most prevalent. We believe this is the first report of occurrence for Ethiopia of A. euteiches, Ph. megasperma, T. basicola, and the five AGs for R. solani. There were very high incidence rates of the foliar pathogens Botrytis cinerea, B. fabae, Didymella pinodes, and Phoma pinodella and of the nematode Pratylenchus thornei, followed by P. neglectus and P. penetrans. The root rot severity and distribution varied significantly across regions, as well as with soil types, soil pH, and soil drainage. Subsequently, metabarcoding of the soil DNA was undertaken using three primer pairs targeting fungi (ITS2), Fusarium species (TEF1 α), and Oomycetes (ITS1Oo). The ITS2 and TEF1α primers emphasized F. oxysporum as the most abundant soilborne fungal pathogen and highlighted F. ananatum, F. brachygibbosum, F. brevicaudatum, F. clavum, F. flagelliforme, F. keratoplasticum, F. napiforme, F. nelsonii, F. neocosmosporiellum, F. torulosum, and F. vanettenii as first reports of occurrence for Ethiopia. The ITS1Oo primer confirmed Pythium spp. as the most prevalent of all Oomycetes. Full article

Plant diseases caused by Rhizoctonia solani present a significant challenge in agriculture. While chemical pesticides remain a common control strategy, their use leads to health and environmental problems. In contrast, endophytic bacteria with plant growth-promoting (PGP) activity offer a promising, sustainable alternative. In this context, a novel endophytic Priestia megaterium strain, KW16, originated from the bluegrass (Poa pratensis L.), demonstrated distinct biocontrol potential against R. solani. in vitro assays showed that KW16 inhibited R. solani growth by up to 58%, primarily by releasing volatile compounds. In planta experiments further highlighted KW16′s ability to colonize oilseed rape internal tissues, significantly enhancing its growth and development. In the presence of the pathogen, KW16 abolished the negative impact of R. solani and promoted plant growth, increasing shoot and root biomass by 216% and 1737%, respectively, when compared to the plants grown in fungal-infested soil. Biochemical and genome analyses confirmed the strain’s metabolic versatility, resistance to biotic and abiotic factors, and a whole spectrum of PGP and biocontrol traits such as biofilm formation, production of phytohormones, and synthesis of lytic enzymes, siderophores, and volatiles, alongside its ability to survive in the presence of autochthonous soil microflora. These findings position KW16 as a potent biological alternative to synthetic fungicides, with significant potential for sustainable crop protection. Full article

Root rot, a globally devastating disease of common bean (Phaseolus vulgaris L.), remains a major constraint on bean production across China. Despite its agricultural impact, the pathogen complex associated with this disease has been poorly characterized in most provinces. To address this critical knowledge gap, we conducted nationwide surveys during 2016–2018, systematically sampling 1–10 symptomatic plants from each of 121 (2016) and 170 (2018) field sites across 17 provinces in China’s major vegetable production regions. Isolates obtained from symptomatic root tissues underwent morphological screening, followed by molecular identification using partial sequences of EF1-α for Fusarium species and ITS regions for other genera. Pathogenicity of representative isolates was subsequently confirmed through controlled greenhouse assays. This integrated approach revealed fourteen fungal and oomycete genera, with Fusarium (predominantly F. oxysporum and F. solani) and Rhizoctonia (R. solani) emerging as the most prevalent pathogens. Notably, pathogen composition exhibited significant regional variation and underwent temporal shifts across developmental stages. Additionally, F. oxysporum, F. solani, and R. solani demonstrated significant interspecies associations with frequent co-occurrence in bean root rot systems. Collectively, this first comprehensive characterization of China’s common bean root rot complex not only clarifies spatial–temporal pathogen dynamics but also provides actionable insights for developing region- and growth stage-specific management strategies, particularly through targeted control of dominant pathogens during key infection windows. Full article

Microplastics and invasive species, driven by anthropogenic activities, significantly disrupt ecosystems and microbial communities. This study investigated the interactive effects of biodegradable microplastics (polylactic acid, or PLA, and polyhydroxyalkanoates, or PHAs) and the fungal pathogen Rhizoctonia solani on the invasive plant Solidago canadensis. One plant of Solidago canadensis/pot was cultivated in forest soil amended with 1% (w/w) microplastics and/or R. solani. PLA exhibited greater toxicity than PHAs, reducing the plant height, root length, and biomass by 68%, 44%, and 70%, respectively. Microplastics impaired the maximum quantum yield of photosystem II more severely than R. solani. However, S. canadensis demonstrated adaptive antioxidative and extracellular enzymatic mechanisms under combined stresses. A heatmap analysis revealed a positive correlation between PHAs and plant growth traits, while a redundancy analysis explained the 15.96% and 4.19% variability for the first two components (r² = 0.95). A structural equation model indicated the negative effects of morphology and physiology on biomass (β = −1.694 and β = −0.932; p < 0.001), countered by positive antioxidant contributions (β = 1.296; p < 0.001). These findings highlight complex interactions among microplastics, pathogens, and invasive species, offering insights into ecological management strategies under dual environmental pressures. Future studies should assess the long-term field effects and microbial mediation of these interactions. Full article

In response to the urgent need for innovative fungicides to ensure food security and safety, a series of twenty-three novel trifluoromethylpyridine compounds were designed and synthesized using a scaffold hopping strategy derived from dehydrozingerone. This approach involved converting the α, β-unsaturated ketone moiety into a pyridine ring. Bioassay results indicated that the majority of these compounds exhibited promising in vitro antifungal activity, particularly against Rhizoctonia solani and Colletotrichum musae. Notably, compound 17 showed the highest efficacy and broad-spectrum activity, with median effective concentrations (EC₅₀) ranging from 2.88 to 9.09 μg/mL. Phenoxytrifluoromethylpyridine derivatives, including compound 17, exhibited superior antifungal activity compared to benzyloxytrifluoromethylpyridine derivatives. In vivo tests revealed that both compounds 17 and 23 exhibited moderate control effects against C. musae. The degradation half-lives of compounds 17 and 23 in bananas were determined to be 176.9 h and 94.8 h, respectively, indicating the stability of their structures in the environment. Molecular docking studies indicated that compound 23 interacts with succinate dehydrogenase, offering valuable insights for the structural optimization of compound 23. Full article

Background/Objectives: Difenoconazole (DFC) is a broad-spectrum fungicide. However, its application is limited due to poor aqueous solubility. Drugs with low solubility can be better absorbed using nanostructured lipid carriers (NLCs). Hence, the application of DFC in an NLC delivery system is proposed. Methods: Difenoconazole-loaded nanostructured lipid carriers (DFC-NLCs) with different solid–liquid lipid ratios were prepared by solvent diffusion method. Key physicochemical parameters, including particle diameter, surface charge (zeta potential), drug encapsulation efficiency, and morphological characteristics, were systematically characterized. Using Rhizoctonia solani (R. solani) as the model strain, inhibitory efficiency of DFC-NLC dispersion was compared with that of commercial dosage forms, such as 25% DFC emulsifiable concentrate (DFC-EC) and 40% DFC suspension concentrate (DFC-SC). Additionally, uptakes of DFC-NLC dispersions in R. solani were further observed by fluorescence probe technology. The safety profiles of DFC-NLCs and commercial dosage forms were evaluated using zebrafish as the model organism. Acute toxicity studies were conducted to determine the maximum non-lethal concentration (MNLC) and 10% lethal concentration (LC₁₀). Developmental toxicity studies were performed to observe toxic phenotypes. Results: DFC-NLC dispersions were in the nanometer range (≈200 nm) with high zeta potential, spherical in shape with encapsulation efficiency 69.1 ± 1.8%~95.0 ± 2.6%, and drug loading 7.1 ± 0.3%~9.7 ± 0.6% determined by high-performance liquid chromatography coupled with tandem mass spectrometry (HPLC-MS/MS). Compared with commercial dosage forms, the antifungal effect of the DFC-NLC on R. solani was significantly improved in in vitro antibacterial experiments (p < 0.05). The 50% effective concentration (EC₅₀) values were 0.107 mg·L⁻¹ (DFC-NLC), 0.211 mg·L⁻¹ (DFC-EC), and 0.321 mg·L⁻¹ (DFC-SC), respectively. The uptakes of FITC-labeled DFC-NLC demonstrated that an NLC was appropriate to deliver DFC into pathogen to enhance the target effect. In safety assessment studies, DFC-NLCs exhibited a superior safety profile compared with commercial formulations (p < 0.05). Conclusions: This study investigates the feasibility of NLCs as delivery systems for poorly water-soluble fungicides, demonstrating their ability to enhance antifungal efficacy and reduce environmental risks. Full article

Potassium has been identified as a vital nutrient for plant growth and functions. Studies have demonstrated its capacity to mitigate the severity of diseases by accelerating seed maturation and promoting robust root system development. In this study, we aimed to determine how increasing potassium doses affect the nutrient content, dry weight, root weight, and resistance to Rhizoctonia rot of the pepper plant. Pepper seedlings were used as plant material, and potassium sulfate was employed as the potassium fertilizer in this study. The experiment involved applying four different potassium doses (0, 50, 100, and 150 kg ha⁻¹) to pepper seedlings, along with RS0 (control) and RS1 (diseased plant) in four replicates. At the end of the study, analyses of the plants’ nitrogen (N), phosphorus (P), potassium (K), magnesium (Mg), calcium (Ca), iron (Fe), manganese (Mn), copper (Cu), zinc (Zn), and boron (B) content, dry weights, and root weights were performed, in addition to disease assessments. An increase in N, P, K, Fe, and B content was observed with applied potassium doses, while a decrease in Mg content was noted. No significant change was detected in Cu content in pepper leaves, and the change in Mn content was not found to be statistically significant. An increase in plant dry weights was determined based on the applied treatments. The results indicated that plants subjected to potassium exhibited resistance to disease, an increase in root weights, and overall better conditions compared to samples without potassium. The best results in the experiments were achieved with the application of 150 kg ha⁻¹ K₂SO₄. It was observed that certain rates of potassium had positive effects on disease factors by suppressing Rhizoctonia rot and can be used for biological control. Full article

With the long-term use of certain types of traditional chemical fungicides, phytopathogen resistance and environmental pollution have made the application of these fungicides face unprecedented challenges. Therefore, using the low toxicity and structural diversity of natural product analogs to develop alternatives has become an important tactic to improve control efficiency and reduce pathogen resistance, as well as environmental risks. In this study, thirty-eight rhein derivatives were synthesized after our continuous efforts aiming to discover new anthraquinone-based antifungal agents. Their structures were characterized by ¹H-NMR, ¹³C-NMR and high-resolution mass spectrometry. The antifungal activities of rhein derivatives were first evaluated against four phytopathogenic fungi. The bioassay results indicated that most derivatives exhibited good antifungal activity against Rhizoctonia solani at 0.5 mM in vitro. Compounds 3e, 3j, 4a, 9d and 10f showed potent activities against R. solani, with inhibition rates over 50% at a low concentration of 0.2 mM in vitro. In particular, compound 10a strongly inhibited the growth of Sclerotinia sclerotiorum, Fusarium graminearum and P. capsica, with EC₅₀ values of 0.079 mM, 0.082 mM and 0.134 mM, respectively, which are comparable to the commercial biofungicide phenazine-1-carboxylic acid (PCA). An in vivo study showed that 10a presented excellent curative and protective activities (92.1% and 91.1%, 0.2 mM) against wheat powdery mildew. The phytotoxicity results indicated that rhein amino acid derivatives could significantly eliminate phytotoxicity to rice and rape and could be safely used in these two crops. The resistance development assay indicated that these rhein derivatives could effectively avoid the risk of resistance development in these two strains of fungi, R. solani and S. sclerotiorum. In conclusion, rhein derivatives can be used for the development of potential agricultural fungicides. Full article

In the realm of sustainable and eco-friendly agriculture, current scientific research emphasizes the development of plant-based bioproducts to mitigate the agricultural footprint resulting from excessive fertilizer and pesticide use. This study investigates the cladodes of Opuntia ficus-indica to screen for bioactive compounds and assess their efficacy against fungal pathogens isolated from infected tomato fruits. Quantitative analysis of the methanolic extract revealed substantial concentrations of bioactive compounds: total polyphenols (86.6 mg GAEs/100 g FW), flavonoids (13.4 mg QEs/100 g FW), condensed tannins (8.9 mg TAEs/100 g FW), and carotenoids (0.9 mg β-CEs/100 g FW). Notably, the DPPH assay indicated that the cladode extract exhibited significant antioxidant potential at a concentration of 0.6 mg/mL. Seven fungal pathogens were isolated from infected tomato fruits and identified as belonging to the following genera: Rhizoctonia (EC2), Fusarium (EC1 and EC3), Alternaria (EC4), Mucor (EC5), Aspergillus (EC6), and Penicillium (EC7). At a concentration of 0.02% of the cladode hydroethanolic extract, the antifungal activity results demonstrated mycelial growth inhibition for Alternaria sp. (70.91%), Rhizoctonia solani EC2 (58.49%), Fusarium oxysporum EC3 (57.63%), and Fusarium solani EC1 (53.13%). Conversely, lower inhibitory activities were observed for Mucor sp. EC5 (31.08%), Aspergillus sp. EC6 (35.14%), and Penicillium sp. EC7 (28.38%). At a concentration of 0.04%, all cladode hydroethanolic extracts inhibited mycelial growth by more than 50%. Furthermore, the highest spore inhibition was attained with the 0.04% cladode hydroethanolic extract (exceeding 50%). Inhibition percentages of 83.02%, 85.96%, 87.76%, and 90.20% were recorded for Fusarium oxysporum EC3, Fusarium solani EC1, Rhizoctonia solani EC2, and Alternaria sp. EC4, respectively. Collectively, these findings suggest that Opuntia ficus-indica extract holds significant promise for application as a biopesticide against fungal pathogens affecting tomato fruits. Full article

Flax (Linum usitatissimum L.) is a plant of high economic and practical importance valued for its fiber and oil, which have diverse applications in industries such as textiles, food, pharmaceuticals, and construction. Fungal pathogens of the genus Fusarium, however, pose one of the most serious threats to flax cultivation. They are responsible for a number of disease manifestations, notably Fusarium wilt and root rot. In the case of fusariosis, there is a lack of plant protection products, and often the only effective approach is to use resistant flax cultivars or to discontinue cultivation for several years. Currently, much attention is paid to biological methods of plant protection, which do not exert a negative influence on the environment or human health and are important for sustainable agriculture. The aim of the present study was to assess the potential of the non-pathogenic endophytic fungal strain Fusarium oxysporum Fo47 in protecting plants against pathogenic fungi. The results showed that pretreatment of flax plants with Fo47 increased resistance of plants to all tested fungi (F. oxysporum, Fusarium culmorum, Rhizoctonia solani). Fo47 was the most effective for protection against F. culmorum for the Jan flax cultivar and R. solani for the Bukoz cultivar. Pretreatment with Fo47 of flax plants inoculated with F. culmorum caused an increase in the level of secondary metabolites involved in plant resistance (phenolics) and photosynthetic pigments (chlorophyll a and b) compared to plants treated only with the pathogenic fungal strain. Fourier transform infrared spectroscopy revealed structural changes in the polymers of cell walls. The highest intensities of vibrations characteristic of lignin and pectin were observed for flax treated with Fo47 and infected with F. culmorum, suggesting the highest level of these polymers, higher than in plants treated only with pathogenic fungi. Thus, it can be concluded that application of the non-pathogenic strain strengthened the immune response of flax plants. These results highlight the strong potential of the non-pathogenic strain as a biological control agent, especially for Fusarium infection in flax. Full article

1,2,4-Oxadiazole derivatives containing anisic acid or cinnamic acid were designed and synthesized, which were expected to be an effective Succinate dehydrogenase (SDH) inhibitor, and their structures were characterized by ¹H NMR, ¹³C NMR, and ESI-MS. The antifungal activity of the compounds against plant pathogenic fungi was screened by the mycelial growth inhibition test in vitro. Compounds 4f and 4q showed significant antifungal activities against Rhizoctonia solani (R. solani), Fusarium graminearum (F. graminearum), Exserohilum turcicum (E. turcicum), Botrytis cinerea (B. cinerea), and Colletotrichum capsica (C. capsica). The EC₅₀ values of 4q were 38.88 μg/mL, 149.26 μg/mL, 228.99 μg/mL, and 41.67 μg/mL against R. solani, F. graminearum, E. turcicum, and C. capsica, respectively, and the EC₅₀ values of 4f were 12.68 μg/mL, 29.97 μg/mL, 29.14 μg/mL, and 8.81 μg/mL, respectively. Compound 4f was better than commercial carbendazim against Exserohilum turcicum. Compounds 4f and 4q showed an antifungal effect on C. capsica of capsicum in vivo. Molecular docking simulation showed that 4f and 4q interacted with the target protein through the hydrogen bond and hydrophobic interaction, in which 4q can form hydrogen bonds with TRP173 and ILE27 of SDH, and 4f had hydrogen bonds with TYR58, TRP173, and SER39. This also explains the possible mechanism of action between the inhibitor and target protein. Full article

Chitosan gel beads represent a promising biopolymer-based delivery system for encapsulating Bacillus subtilis, an effective biocontrol agent in sustainable agriculture. This study investigates the influence of chitosan molecular weight on bead structure, water retention, and swelling behavior, as well as its impact on the viability and antifungal activity of encapsulated B. subtilis. The results demonstrate that chitosan provides a protective microenvironment, enhancing microbial viability, promoting colonization, and ensuring controlled release for prolonged plant protection. Moreover, encapsulation within chitosan gel beads preserved bacterial viability during long-term storage for up to 90 and 180 days. Additionally, the biodegradable and antimicrobial properties of chitosan contribute to pathogen suppression while supporting the plant growth-promoting activities of B. subtilis. The encapsulated bioagent exhibited strong antifungal activity against Fusarium avenaceum and Rhizoctonia solani, highlighting the effectiveness of this eco-friendly approach as an alternative to chemical pesticides. These findings underscore the potential of chitosan-based formulations to enhance the efficacy of bioinoculants, offering a sustainable solution for modern crop management. Full article

Endophytic fungi provide valuable sources for the discovery of secondary metabolites that can be used as lead compounds in drug discovery. In this study, four new sesquiterpenoids with a farnesane backbone, schizophyllol A–B (1–2) and schizophylloside A–B (3–4), together with five known analogues (5–9), were isolated from the plant-derived fungus Schizophyllum sp. HM230. Their structures were established through extensive spectroscopic analyses including HR-ESI-MS and 1D and 2D NMR. The antioxidant activities of all the isolated compounds (compounds 1–9) were evaluated via hydroxyl radical scavenging, DPPH free radical scavenging, and superoxide anion radical scavenging assays. Compounds 1 and 2 displayed stronger antioxidant capacities than the positive control tert-butylhydroquinone. Furthermore, the antifungal activities of the isolated compounds were evaluated against four phytopathogenic fungi: Sclerotinia ginseng, Rhizoctonia solani, Cylindrocarpon destructans, and Exserohilum turcicum. All the test compounds demonstrated inhibitory effects; notably, compound 4 exhibited the strongest activities against the four selected phytopathogenic fungi, with inhibitory rates ranging from 42.3% to 65.4% at 0.2 mg/mL. Full article