Physio-biochemical and transcriptomics analyses reveal molecular mechanisms of enhanced UV-B stress tolerance in rice induced by titanium dioxide nanoparticles

Rice (<i>Oryza sativa</i> L.) stands out as the world's most vital staple food crop, yet is susceptible to UV-B radiation stress. This study investigates the physiological and transcriptome responses in rice exposed to titanium dioxide nanoparticles (TiO₂ NPs) under UV-B radiation. Results demonstrate that TiO₂ NPs, applied alone (TN) or in combination with UV-B stress (UV+TN), significantly enhance rice plant growth and physiological parameters. Reactive oxygen species (ROS) levels, elevated under UV-B stress, are significantly reduced by TN and UV+TN treatments, thereby regulating antioxidants particularly involved in ascorbate-glutathione pathway. Transcriptomics analysis of identified DEGs in UV+TN, utilizing KEGG pathway analysis, reveals significant enrichment in various pathways. These pathways include glutathione metabolism, pyruvate metabolism, starch and sucrose metabolism, regulation of basal transcription factors, plant hormonal signal transduction pathways, cellular processes associated with energy, and the MAPK signaling pathway. Overall, TiO₂ NPs application modulates diverse biological and metabolic pathways, enhancing UV-B stress tolerance in rice.