Mechanistic Insight of the Antifungal Potential of Green Synthesized Zinc Oxide Nanoparticles against Alternaria brassicae

Abstract

Alternaria brassicae is a necrotrophic fungus causes Alternaria blight disease in oilseed mustard crop. There is a 47% loss of the mustard crop due to the Alternaria blight disease. To control this disease, various chemical fungicides have been used till date which are harmful to our environment. Zinc oxide (ZnO) nanoparticles synthesized from Terminalia bellerica have been reported to have significant antifungal potential against A. brassicae at 200 ppm concentration. In the present study, the effect of green synthesized zinc oxide (Tb-ZnO) nanoparticles, chemically synthesized ZnO nanoparticles, and chemical fungicides on A. brassicae has been anticipated by analysing changes in cytomorphology characteristics, biochemical constituent, and stress enzymes of A. brassicae. Cytomorphological studies by transmission electron microscopy and scanning electron microscopy have shown the complete disintegration of cell wall, cell membrane, and cytoplasmic content at 200 ppm concentration of Tb-ZnO nanoparticles. Decrement in biochemical constituents and changes in activity of stress enzymes in Tb-ZnO nanoparticles treated cell confirm the toxicity of nanoparticles at 200 ppm concentrations. Hence, on the basis of all these results, the mechanism of action of Tb-ZnO nanofungicides on A. brassicae has been hypothesized in the present study. This study confirms how nanoparticles inhibit the growth of A. brassicae and suggested the use of nanofungicides.

Mechanistic insight into the anti-alternaria activity of bimetallic zinc oxide and silver/zinc oxide nanoparticles

“…4 a–c). Different studies have reported on the antifungal activities of Ag and ZnO nanoparticles against different pathogenic fungi [ 2 , 6 , 7 , 26 , 29 , 30 , [34] , [35] , [36] , [37] , [38] , [39] ]. Furthermore, the findings from this study also agrees with previous reports by Dhiman et al [ 33 ] and Kumar et al [ 11 ] who independently reported on the antifungal potential of ZnO nanoparticles against Alternaria brassicae, Penicillium funiculosum, Aspergillus niger and Fusarium oxysporum and Candida albican.…”

“…The effect of ZnO and bimetallic Ag/ZnO nanoparticles on the morphological and ultrastructural alterations of A. alternata was determined using HRSEM and HRTEM techniques as reported by Dhiman et al [ 7 ] and Daniel et al [ 16 ].…”

“…Extracellular and intracellular polysaccharides contents of fungal mycelia treated with the nanoparticles according to a modified protocol reported by Dhiman et al [ 7 ]. The amount of intracellular extracellular polysaccharides was quantified using Anthrone method.…”

“…However, excessive use of chemical fungicides has led to downstream side effects including the emergence of resistant pathogen strains, soil acidification, groundwater contamination, and destruction of ecosystems which can negatively impact human and animal health [ 1 , 6 ]. An alternative to chemical control is the use of biocontrol agents, which is a suitable substitute for these fungicides [ 7 ]. Maintaining hygiene standards and inconsistent application are problems associated with employing microbes as biocontrol agents.…”

“…Metallic nanoparticles made of metal or non-metallic oxides could serve as alternative to the chemical control strategies. Biologically derived nanoparticles have emerged as a promising tool for controlling disease causing pathogens in food crops due to their low toxicity profile [ 7 ].…”