Antifungal activity of myco-synthesized bimetallic ZnO-CuO nanoparticles against fungal plant pathogen Fusarium oxysporum

Abstract

Abstract Fusarium species are considered one of the most destructing plant pathogens. In the current study, bimetallic zinc oxide-copper oxide nanoparticles (ZnO-CuO NPs) were myco-synthesized using Aspergillus fumigatus for controlling Fusarium oxysporum growth. Aspergillus fumigatus was isolated from soil and identified morphologically and genetically. The myco-synthesized ZnO-CuO NPs were characterized using UV-Vis, DLS, HR-TEM, SEM, and XRD analyses. HR-TEM characterization method indicated that, the biosynthesized bimetallic ZnO-CuO NPs appeared as semi-spherical with the average diameter specified as 54.18 ± 1.9 nm. The DLS method described the characteristic particle size diffusion and was calculated as 85.52 nm, 90.85 nm, and 92.85 nm for ZnO NPs, CuO NPs, and ZnO-CuO NPs, respectively. Additionally, the SEM image of ZnO-CuO NPs displays basic NP surface character and the exterior impression was apparent. The biosynthesized ZnO-CuO NPs were separated naturally as spherical particles connected within the fungal filtrate, which displays as illuminated NPs fused and capped with the fungal filtrate. Antifungal activity of bimetallic ZnO-CuO NPs was evaluated against F. oxysporum. Results revealed that bimetallic ZnO-CuO NPs exhibited promising antifungal activity toward F. oxysporum where inhibition zone at 1000 µg/ml was 22.8 ± 0.76 mm, and MIC was 125 µg/ml. Moreover, growth inhibition percentages of F. oxysporum at different concentrations of bimetallic ZnO-CuO NPs 1000, 500, 250, and 125 µg/ml were 88.9, 65.5, 41.1, and 8.9% respectively, where the highest inhibition was 88.9% at concentration 1000 µg/ml, while the lowest inhibition was 8.9% at concentration 125 µg/ml. In TEM ultrastructure results, the treated F. oxysporum with ZnO-CuO NPs, a clear destruction was found in all cell contents and disintegration of the cell wall as well as destruction of the plasma membrane. Also, the nucleus appeared as small size and damaged shape and the chromatin materials distributed with several dark stained bodies in cytoplasm. In conclusion, bimetallic ZnO-CuO NPs were successfully myco-synthesized using A. fumigatus, where it had promising antifungal activity against F. oxysporum.