Use of Metallic Nanoparticles and Nanoformulations as Nanofungicides for Sustainable Disease Management in Plants

Abstract

For plant protection, reliance on agrochemicals is not a sustainable measure, because of the inadequate bioavailability of their active ingredients. Use of synthetic fungicides in controlling plant fungal diseases is routine. The permeability and solubility of active compounds in fungicides determine their bioavailability. Extensive use of fungicides for disease management results in pollution and hazardous impacts on the ecosystem. In this era of modern technologies, nanotechnology provides a smart solution to this problem at the nanoscale level. Synthesis of nanoparticles through physical, chemical, and biological methods is an emergent field of nanotechnology. Nanoparticles are used in making different nanoformulations, nanoemulsions, and nanocapsules. Among all nanoparticles, use of metallic nanoparticles in formulating nanofungicides is common. These nanofungicides offer targeted delivery, enhanced bioavailability due to greater solubility and permeability, small doses, less dose-dependent toxicity, and controlled release. The kingdom Fungi is a diverse group of organisms, and synthetic fungicides are not always effective against all phytopathogenic fungi. Thus, in this scenario, nanoparticles can be used as alternative control measures because of their ability to permeate through biomembranes and their large surface areas, which are attributed to their extremely small size. Among metallic nanoparticles, silver nanoparticles have strong antifungal potential. Silver ions inactivate thiol groups in the fungal cell wall, resulting in cell lysis and DNA mutation, thereby disrupting membrane processes (such as the membrane electron transport chain and transmembrane energy metabolism) and dissociating enzyme complexes, and ultimately blocking the respiratory chain in the fungus. The relationship between the size of nanoparticles and their efficiency and antifungal potential is an inverse one. This chapter provides comprehensive knowledge of nanoparticles, metallic nanoparticles, nanoformulations, nanofungicides, and their roles in disease management in plants. It also provides insight into the miraculous properties of these particles at the nanoscale.