Reduced Graphene Oxide Nanosheet-Decorated Copper Oxide Nanoparticles: A Potent Antifungal Nanocomposite against Fusarium Root Rot and Wilt Diseases of Tomato and Pepper Plants

Abstract

Sustainable use of nanotechnology in crop protection requires an understanding of the plant’s life cycle, potential toxicological impacts of nanomaterials and their mechanism of action against the target pathogens. Herein, we show some properties of a candidate antifungal nanocomposite made from copper oxide (CuO; otherwise an essential soil nutrient) nanoparticles (NPs), with definite size and shape, decorating the surface of reduced graphene oxide (rGO) nanosheets. The successful preparation of the rGO-CuO NPs was confirmed by spectroscopic and microscopic analyses, and its antifungal activity against wild strains of Fusarium oxysporum affecting tomato and pepper plants was successfully confirmed. A comparative analysis in vitro indicated that this nanocomposite had higher antifungal activity at only 1 mg/L than the conventional fungicide Kocide 2000 at 2.5 g/L. Further investigation suggested that rGO-CuO NPs creates pits and pores on the fungal cell membranes inducing cell death. In planta results indicated that only 1 mg/L from the nanocomposite is required to reduce Fusarium wilt and root rot diseases severity below 5% for tomato and pepper plants without any phytotoxicity for about 70 days. Comparatively, 2.5 g/L of Kocide 2000 are required to achieve about 30% disease reduction in both plants. The present study contributes to the concept of agro-nanotechnology, showing the properties of a novel ecofriendly and economic nanopesticide for sustainable plant protection.

Influence of Copper Oxide Nanoparticles on Gene Expression of Birch Clones In Vitro under Stress Caused by Phytopathogens

“…As we expected, CuO NPs had pronounced concentration-dependent antifungal effects on phytopathogens in culture. This is consistent with the results of a number of previous studies, where the authors demonstrated the suppression of the phytopathogenic fungi growth such as Botrytis cinerea [ 52 ], F. oxysporum [ 53 ], Aspergillus sp., A. alternata [ 54 ], Fusicladium oleagineum , and Colletotrichum sp. [ 55 ].…”

Advances in Biologically Applicable Graphene-Based 2D Nanomaterials

“…CuO NPs decorated with rGO, applied at a dose of 1 mg/L, exhibited higher antifungal activity against F. oxysporum in vitro than 2.5-fold higher dose of the conventional fungicide Kocide ® 2000, whereby CuO NPs−rGO caused death of fungal cells by creating pits and pores on the fungal cell membranes. In an experiment with F. oxysporum -infected tomato and pepper plants, a dose of 1 mg/L CuO NPs−rGO was able to reduce Fusarium wilt and root rot diseases severity by >5% for 70 days, whereby phytotoxic effects were not observed; with application of Kocide ® 2000 at a dose 2.5 mg/L, only 30% disease reduction was observed [ 198 ]. Combination of rGO with cationic polymer can improve the binding of rGO on leaf surface of chili crop by more than 30%, compared to control, and diminish its leaching in soil by 45% more than control.…”

Recent Advances in Plant Nanoscience

“…[ 171 ] Therefore, in another study, the researchers prepared rGO‐CuO nanocomposite through chemical precipitation method, and studied its antifungal activity against wild strains of Fusarium oxysporum . [ 172 ] With the help of rGO, the CuO NPs become more stable and more soluble in water. And the antifungal activity of the rGO‐CuO nanocomposite with smaller size of CuO NPs (5 nm) was the best.…”