Application of magnesium oxide nanoparticles as a novel sustainable approach to enhance crop tolerance to abiotic and biotic stresses

Abiotic stresses (heavy metals, drought, salinity, etc.) or biotic pathogens (bacteria, fungi, nematodes, etc.) contribute to major losses in crop yields. Improving the crop yield under these environmental constraints is critical to assure the food supply and sustainable agriculture. Magnesium oxide nanoparticles (MgONPs) are non-toxic, eco-friendly, and highly stable materials that have wider opportunities for their production at the nanoscale. Differently synthesized MgONPs have been found to induce plant resistance against these stresses via a combination of physiochemical and molecular pathways that strengthen the structural barriers, improve nutrient availability, osmoregulation, photosynthetic efficiency, hormonal regulation, activate antioxidant defense systems, stress-responsive genes, thereby enable plant adaptation to environmental stressors. MgONPs act as antibacterial, antifungal or nematicidal agents that inhibit the growth of plant pathogens and reduce pathogen colonization, thereby reducing the disease incidence against biotic stresses. In this review, we discuss the multifaceted mechanisms of MgONPs in managing the abiotic and biotic stresses thus, imparting plant protection. In addition, knowledge gaps along with research questions and future recommendations are delineated in this review.