Titanium dioxide nanoparticles TiO2 NPs in crop stress management: Mechanisms, applications, and abiotic stress mitigation

Abiotic stresses significantly reduce global crop productivity by impairing physiological, biochemical, and molecular functions. Nanotechnology, particularly titanium dioxide nanoparticles (TiO 2 NPs), has emerged as an innovative approach to enhance plant resilience under severe environmental conditions. This review synthesizes recent experimental findings on TiO 2 NP biosynthesis and their protective roles against major abiotic stresses, including drought, salinity, heavy metal toxicity, temperature extremes, and UV radiation. TiO 2 NPs regulate photosynthetic efficiency, nutrient balance, ROS homeostasis, strengthen enzymatic and non-enzymatic antioxidant defenses, stabilize cellular membranes, osmolytes accumulation, and stress-responsive gene expression, thereby enhancing stress tolerance. The synergistic applications of TiO 2 NPs with other nanoparticles, phytohormones, and biochar establish additional regulatory networks to manage abiotic stresses. Despite promising results, challenges remain regarding inconsistent formulations, dose-dependent toxicity, environmental interactions, and limited field-scale validation. Addressing these gaps through optimized formulations, omics-based mechanistic studies, and biosafety assessments will support the safe and effective integration of TiO 2 NP technology into sustainable crop production under changing climate conditions. Schematic demonstrating the dual role of abiotic stress-induced toxicity, left panel (drought, heat, cold, salinity, and heavy metal stress), and the right panel shows the types of TiO 2 NPs and their use of application routes, seed priming, and foliar application, TiO₂ NPs, synthesized via green synthesis from plants, microorganisms. • TiO₂ NPs boost plant tolerance to drought, salinity, heat, cold, UV, and heavy metals. • Benefits are dose dependent, with toxicity risks at excessive concentrations. • TiO₂ NPs trigger ROS, NO, Ca²⁺, MAPK, and hormone regulated stress pathways. • Combining TiO₂ NPs with other agents improves efficiency and eco-safety. • This review integrates mechanisms with safe, sustainable agricultural use.