In vitro antimicrobial effect of metallic nanoparticles on phytopathogenic strains of crop plants

Abstract

In this research, the in vitro antimicrobial effect of zinc oxide (ZnO), copper oxide (CuO) and iron oxide (Fe2O3) nanoparticles (NPs)—with average sizes of 20, 46 and 30 nm, respectively—on the root rot disease caused by the fungus Fusarium oxysporum and on blight disease caused by the fungus Alternaria solani were studied. Also, bacterial diseases caused by Clavibacter michiganensis and Pseudomonas syringae that infects a wide range of plant species were assessed. Different concentrations of NPs (0, 100, 250, 500, 700 and 1,000 mg/L) were prepared on PDA agar or King's B medium in a complete randomized design with four replicates. According to the results, ZnO NPs exhibited an outstanding inhibitory effect against fungi and bacteria strains. The above results were associated with the smaller particle size. Fungi strains showed a differential sensitivity depending on the kind of NPs used. A. solani showed the highest sensitivity to ZnO NPs at 1,000 mg/L (99%), followed by CuO NPs at the same dose (95%). Fe2O3 NPs at all evaluated doses had no inhibitory effects on the mycelia growth of this strain, although F. oxysporum revealed greater effectiveness of the CuO NPs (96%) compared with ZnO NPs since it only inhibited 91% of the mycelial growth. The antibacterial activity was studied through optical density. C. michiganensis was found to be more sensitive to ZnO NPs because a lesser dose (700 mg/L) was required to reduce the bacterial growth (90%); in comparison, P. syringae required a dose of 1,000 mg/L to inhibit its growth (67%). CuO NPs displayed the smallest growth inhibition against the bacteria strains analysed. The antimicrobial effect of the metallic NPs that were assayed increased with higher doses.

Biocontrol potential of mycogenic copper oxide nanoparticles against Alternaria brassicae

“…Plant extract-mediated CuO NPs have minimum inhibitory concentration (MIC) and minimum fungicidal concentration (MFC) at 25, 100, and 1000 mg/ml. Moreover, the fungal filtrate-synthesized CuO NPs were found to be efficient at 25–250 ppm dose ( Giannousi et al, 2013 ; Vera-Reyes et al, 2019 ). Thus, all these studies have showed that lower doses of CuO NPs (25–1,000 ppm) are sufficient to kill the pathogen, which are supporting the antifungal activity of our M-CuO NPs (25–200 ppm).…”

Myco-Suppression Analysis of Soybean (Glycine max) Damping-Off Caused by Pythium aphanidermatum

“…Root damping-off diseases are widely disturbed all over the world and are recognized as a serious problem to soybean cultivators, as they significantly decrease the bean yield. Several control measures of the disease are available, including fungicidal control, enhancement of genetic resistance, which may lead to deteriorating human health [5,20]. In Egypt, there is no active control method to reduce damping-off of many crops and vegetable plants caused by P. aphanidermatum although, that pathogenic is widely distributed throughout the country [17,18,21,22].…”

“…Root rot diseases of G. max are widespread in the world and are usually recognized as the main constraint to decrease both yield and quality [2,3]. Pythium as a causal agent for Glycine max root rots has been mentioned as being the main reason leading to soybean yield losses in numerous countries [4,5]. Pythium aphanidermatum has been reported as the species most frequently causing root rot diseases for the greatest variety of crops [4].…”

“…The use of chemical fungicides controlling such diseases could lead to degenerating human health, environmental pollution, and the development of pathogen resistance to fungicides. Biological methods are needed for plant protection which are less dependent on chemicals and are more environmentally favorable [5,6].…”

Engineered Metal Oxide Nanoparticles as Fungicides for Plant Disease Control

“…Research works have also showed that other factors, such as the concentration of nanoparticles used to inhibit the growth of phytopathogenic fungi and characteristics of fungal species, influence the antifungal activity [87]. In general, the inhibition of phytopathogenic fungi tends to increase under in vitro evaluations when the concentration of the ZnO-NPs increases [46,[48][49][50][51]53,54,60,[63][64][65][66][67][69][70][71][72][73][74][75][76][77][78][79][80][81][82][83][84][85]. Interestingly, low concentrations (100-1000 ppm) of ZnO-NPs have shown excellent results for controlling phytopathogenic fungi.…”