Abstract

The antifungal efficiency of Zinc oxide nanoparticles (ZnO NPs) was investigated against two pathogenic fungal species, F. oxysporum and P. expansum. The two fungi were identified at molecular level by nuclear ribosomal DNA internal transcribed spacer (ITS) identities. They have been submitted to the GenBank with accession numbers of AB753032 and AB753033 for F. oxysporum and P. expansum, respectively. The antifungal activity of ZnO NPs was found to be concentration dependent. Hence, maximal inhibition of mycelial growth corresponded to the highest experimental concentration (12 mg L⁻¹), where 77 and 100% growth inhibition was observed for F. oxysporum and P. expansum, respectively. The effect of ZnO NPs on the mycotoxins fusaric acid and patulin production by F. oxysporum and P. expansum, respectively, was investigated using HPLC quantification. It was observed that ZnO NPs prevented both mycotoxins synthesis in a concentration dependent manner. Fusaric acid was reduced from 39.0 to 0.20 mg g^-1while patulin production was reduced from 14.2 to 1.10 mg g^-1 in control and 12 mg L⁻¹ZnO NPs treated samples, respectively. The scanning electron microscopy (SEM) revealed obvious deformation in the growing mycelia treated with ZnO NPs in F. oxysporum which may be the cause of growth inhibition.

Key words: Zinc Oxide Nanoparticles (ZnO NPs), antifungal efficiency, Fusarium oxysporum, Penicillium expansum.