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Metabolites from biomass of Trichoderma harzianum were used for green synthesis of zinc oxide nanoparticles (ZnONPs) from zinc nitrate (ZnNO3) and GC/MS analysis of metabolite was performed. Then, the antifungal activity of synthesized ZnONPs was evaluated against Fusarium oxysporum under the laboratory and greenhouse conditions. Results were compared to different concentrations of Iprodione + Carbendazim (Rovral-TS®) fungicide. Synthesized ZnONPs were characterized by ultraviolet-visible spectrometry (UV-Vis), X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM) and fourier transform infrared spectroscopy (FTIR). UV-Vis spectra showed an intense peak at 339 nm. X-ray diffraction pattern showed the crystalline nature and purity of the ZnONPs. FTIR revealed various functional groups including phenols, ketones, aldehydes, aliphatic and primary amines, nitriles, alkanes and alkynes in synthesized ZnONPs. Size of ZnONPs determined in the range from 25–60 nm. Based on atomic absorption spectroscopy, foliar application of synthesized ZnONPs, led to considerable accumulation of zinc in the leaves and suitable for compensate zinc deficiency. Some growth factors including root length, root volume, stem length, stem diameter and number of leaves improved in the treatments containing metabolite of T. harzianum, ZnNO3 and ZnONPs. Complete inhibition of mycelia growth of F. oxysporum was observed in 100 µg/ml concentration of ZnONPs in the laboratory conditions and disease percentage significantly reduced in the greenhouse conditions, indicated that green synthesized ZnONPs gave better results in low concentration than the fungicide. Therefore, application of green synthesized ZnONPs could be recommended as effective alternative and eco-friendly method for crop protection instead chemical fungicides.

Introduction: Fusarium graminearum produces trichothecenes, such as deoxynivalenol and secondary metabolite butenolide, which cause profound health problems in humans. In this research, the effect of acetone extract of Hibiscus sabdariffa is evaluated on growth of F. graminearum and expression of TRI4 and FG08079 genes, which are involved in deoxynivalenol and butenolide biosynthetic pathways, respectively. Methods: Minimal inhibitory concentration (MIC) and minimum fungicidal concentration (MFC) were determined. The expression of TRI4 and FG08079 genes were evaluated by teal-time PCR technique.Results: The MIC and MFC for acetone extract of Hibiscus sabdariffa against F. graminearum were 200 mg/mL and 400 mg/mL, respectively. Expression of TRI4 and FG08079 genes were significantly decreased by the acetone extract of red tea. Conclusion: The results showed that acetone extract of Hibiscus sabdariffa has inhibitory and fungicidal effects on F. graminearum and is effective in reducing the expression of TRI4 and FG08079 genes, which play important roles in deoxynivalenol and butenolide production.