Boron nanoparticles combined with auxin alleviate salinity-induced oxidative stress in Oryza sativa L.

The agriculture sector is encountering a range of challenges globally, driven by global climate changes and resource constraints. Crop production is restricted by numerous abiotic factors including salinity stress which negatively influences the physiological, biochemical and molecular responses of plants. Several studies demonstrated that some nanoparticles may enhance crop production by directly boosting the tolerance of plants aganist the salinity stress. In this study, the protective role of boron nitride nanoparticles (BNPs) was determined in two rice cultivars which differ in salinity tolerance (P44 and PB150). Our results showed that exogenous application of BNPs alone and along with IAA alleviated toxic impact of NaCl stress by reducing the over production of oxidative stress markers and thus, promoting growth traits, chlorophyll content, carotenoids, activities of antioxidant enzymes and nitric oxide production in both the rice cultivars. The results showed that boron nanoparticle stimulated activities of the ascorbate-glutathione cycle enzymes under NaCl stress (APX, MDHAR, DHAR and GR). Moreover, BNPs also stimulated relative gene expression of the AsA-GSH cycle enzymes (OsAPX, OsMDHAR, OsDHAR and OsGR1), auxin transporter gene (AUX1 and PIN1) and nitric oxide content under NaCl stress in both cultivars. Furthermore, our study suggests that IAA acts in a synergistic way with BNPs to mitigate NaCl stress in both rice cultivars probable by involving endogenous NO. Collectively results suggested that the combination of BNPs and IAA can be used to prevent NaCl stress which is important for promoting food security.