Phytonanotechnology in the mitigation of biotic and abiotic stresses in plants

Recent years have witnessed a surge in nanoparticles (NPs) based research due to their unique physiochemical properties and their broad range of applications in a variety of sectors, including agriculture. A growing body of evidence suggests that NPs may effectively be used to ameliorate the negative effects of biotic and abiotic stresses in plants. Based on the literature evidence, we have concluded that NPs improve stress tolerance in plants by (1) inducing the detoxification of stress-induced reactive oxygen species (ROS), (2) improving photosynthetic parameters, and (3) triggering the production of compatible solutes, secondary metabolites, and phytohormone(s). Moreover, NPs have also been shown to trigger the signaling cascades which result in the biosynthesis of antimicrobial compounds and expression of defense-related genes, especially under biotic stress conditions. However, higher concentrations of NPs may exhibit negative effects on plant growth and productivity, therefore, an in-depth understanding of NPs behavior in the plants is required for the development of a functional product that can be utilized in modern agricultural practices. This review consolidates the available research on NPs-mediated biotic and abiotic stress tolerance in plants to present an underlying mechanism of NP functions under stress conditions.