ANTIFUNGAL ACTIVITIES OF MAGNESIUM CHLORIDE AND MAGNESIUM OXIDE

ABSTRACT

The aim of this research was to study the antifungal effects of magnesium chloride and magnesium oxide nanoparticles (MgCl2NPs and MgONPs) on phytopathogens isolated from tomato (Solanum lycopersicum L.) leaves. Biological synthesis of MgCl2NPs and MgONPs was carried out using Vernonia amygdalina leaf extract, magnesium oxide and magnesium chloride precursor solutions. The nanoparticles were characterized using Vis spectrophotometry after 24 and 48 hours of synthesis. The maximum absorbance value for the characterization was 1.5 at 400nm and 1.7 at 400nm for 24 and 48 hours respectively for MgONPs and 1.1 at 400nm and 1.6 at 400nm for 24 and 48 hours respectively for MgCl2NPs. In order to investigate the effects of MgCl2NPs and MgONPs on mycelia growth, A phytopathogen was isolated from diseased tomato leaves. The fungal isolate was grown on potato dextrose agar (PDA) using poison plate method with different concentrations of MgCl2 and MgONPs (0%, 50% and 100%), a known antifungal agent (ketoconazole) and bitterleaf extracts as controls. The rate of mycelia growth of the fungal isolate was recorded at 2, 4 and 6 days after inoculation. The isolated fungal phytopathogen was morphologically identified as Aspergillus sp. from diseased tomato leaf. It was observed that the 100% concentration of MgONPs synthesized using bitterleaf exteract offered the highest inhibitory activity at 3.91%, while no visible inhibitory activity was observed in the controls. Meanwhile, there was no notable inhibition observed for MgCl2NPs . The findings from this study suggests that MgONPs synthesized with bitterleaf showed inhibitory properties against the isolated pathogens. The future directions to the study are molecular identification of isolate and in vivo study to investigate the crop protection ability of MgONPs againstphytopathogens.