A decade of nanotechnology in maize (Zea mays): Benefits, risks, and future directions

Maize ( Zea mays ) is a staple crop globally, and the application of nanotechnology holds great promise in enhancing maize growth, resilience, and yield. While various studies have reported the effects of several metallic, metalloid, and non-metallic-based nanomaterials (NMs) in maize, the full extent of their benefits, risks, and influencing factors remains to be fully understood. This systematic review of the last decade adhered to the PRISMA methodology. It examined 74 cutting-edge studies on the impact of NMs used as nanofertilizers for germination, plant growth, and abiotic stress alleviation, as nanopesticides, and the risks of NMs as toxic agents. We observed that NM-effects can be limited by influencing factors such as size, chemical composition, oxidation state, shape, surface chemistry, delivery system, exposure time, and concentration. Concentration might interplay with the exposure time, which is a crucial factor influencing a hormetic behavior of NMs in maize. NMs based on Zn, Ti, Ag, Fe, Mg, Se, and HA enhance imbibition and nutrient uptake, promoting Reactive Oxygen Species (ROS) production, and stimulating metabolic activity. In growth, NMs can up-regulate genes associated with essential metabolic processes, and the mitigation of abiotic and biotic stress has also been observed. This summary provides crucial insights into the role of nanotechnology in optimizing maize production. However, it also highlights the need for further research to fully understand this role, identify research gaps, and suggest directions for future studies in this rapidly evolving field. • NMs can enhance maize germination, growth, stress resilience, and yield. • The properties of nanomaterials (NMs) influence their effects on maize. • Hormetic behavior has been observed in NMs, such as Ti, Ag, Zn, and Se-based. • Biogenic NMs have a higher concentration threshold than chemically synthesized NMs. • Non-metallic-based NMs pose fewer risks than metallic and metalloid-based NMs.