Comparative study of the ability of green synthesized Se-NPs and CTS-NPs to overcome drought stress in Oryza sativa L. for regenerative nanoengineering in agriculture†

The scarcity of freshwater poses a significant challenge to agricultural sustainability, endangering global food security. Rice (Oryza sativa L.), which serves as a staple food for more than half the world's population, is particularly vulnerable to water scarcity. Nano-scale bioengineering offers an innovative approach to mitigate various abiotic stresses such as drought. Selenium nanoparticles (Se-NPs) and chitosan nanoparticles (CTS-NPs) are well known for their beneficial roles in achieving sustainable engineering goals in agriculture crop production. In this study, green-synthesized Se-NPs and CTS-NPs, derived from Acacia modesta leaf extract, were used to impart drought tolerance in Super Basmati rice. The seeds were primed with two concentrations of nanoparticles (6 mg L⁻¹ and 12 mg L⁻¹) were grown in a hydroponic system under a controlled environment. Artificial drought was then introduced using 7.5% and 15% polyethylene glycol (PEG) for three days. The NPs treatments at 12 mg L⁻¹ significantly improved plant growth, biomass, and photosynthetic pigments under drought stress. The Se-NPs increased antioxidant activity by 42% in shoots and 37% in roots, while the CTS-NPs increased it by 39% and 41%, respectively. Whereas proline levels were decreased in the shoots by 28% following Se-NPs treatment and by 25% following CTS-NPs treatment. These findings highlight the potential of the Se-NPs and CTS-NPs as an eco-friendly and sustainable solution against drought stress in rice. Future research should focus on unraveling the molecular mechanisms behind the drought tolerance induced by the NPs along with additional field trials to confirm the practicality of this approach.