Lignin-containing cellulose nanofiber-selenium nanoparticle hybrid enhances tolerance to salt stress in rice genotypes

Soil salinization poses a significant challenge for rice farming, affecting approximately 20% of irrigated land worldwide. It leads to osmotic stress, ionic toxicity, and oxidative damage, severely hindering growth and yield. This study investigates the potential of lignin-containing cellulose nanofiber (LCNF)-selenium nanoparticle (SeNPs) hybrids to enhance salt tolerance in rice, focusing on two rice genotypes with contrasting responses to salt stress. LCNF-SeNP hybrids were synthesized using a microwave-assisted green synthesis method and characterized through FTIR, X-ray diffraction, SEM, TEM, and TGA. The effects of LCNF/SeNPs on seed germination, physiological responses, and gene expression were evaluated under varying levels of NaCl-induced salt stress. Results indicated that LCNF/SeNPs significantly enhanced the salt tolerance of the salt-sensitive genotype IR29, as evidenced by increased germination rates, reduced salt injury scores, and higher chlorophyll content. For the salt-tolerant genotype TCCP, LCNF/SeNPs improved shoot lengths and maintained elevated chlorophyll levels under salt stress. Furthermore, LCNF/SeNPs improved ion homeostasis in both genotypes by reducing the Na⁺/K⁺ ratio, which is crucial for maintaining cellular function under salt stress. Gene expression analysis revealed upregulation of key salt stress-responsive genes, suggesting enhanced stress tolerance due to the application of LCNF/SeNPs in both genotypes. This study underscores the potential of LCNF/SeNPs as a sustainable strategy for improving crop performance in saline environments.