Effect of green Fe2O3 nanoparticles in controlling Fusarium fruit rot disease of loquat in Pakistan

Abstract

The subtropical fruit known as the loquat is prized for both its flavour and its health benefits. The perishable nature of loquat makes it vulnerable to several biotic and abiotic stressors. During the previous growing season (March-April 2021), loquat in Islamabad showed signs of fruit rot. Loquat fruits bearing fruit rot symptoms were collected, and the pathogen that was causing the disease isolated and identified using its morphology, microscopic visualisation, and rRNA sequence. The pathogen that was isolated was identified as Fusarium oxysporum. Green synthesized metallic iron oxide nanoparticles (Fe₂O₃ NPs) were employed to treat fruit rot disease. Iron oxide nanoparticles were synthesized using a leaf extract of the Calotropis procera. Characterization of NPs was performed by different modern techniques. Fourier transform infrared spectroscopy (FTIR) determined the existence of stabilizing and reducing compounds like phenol, carbonyl compounds, and nitro compounds, on the surface of Fe₂O₃ NPs. X-ray diffraction (XRD) explained the crystalline nature and average size (~49 nm) of Fe₂O₃ NPs. Energy dispersive X-ray (EDX) exhibited Fe and O peaks, and scanning electron microscopy (SEM) confirmed the smaller size and spherical shape of Fe₂O₃ NPs. Following both in vitro and in vivo approaches, the antifungal potential of Fe₂O₃ NPs was determined, at different concentrations. The results of both in vitro and in vivo analyses depicted that the maximum fungal growth inhibition was observed at concentration of 1.0 mg/mL of Fe₂O₃ NPs. Successful mycelial growth inhibition and significantly reduced disease incidence suggest the future application of Fe₂O₃ NPs as bio fungicides to control fruit rot disease of loquat.

Keywords: Calotropis procera; Fe2O3 NPs; Fruit rot; Fusarium oxysporum; Green synthesis; NPs characterization.