Selenium nanoparticles induce differential shoot/root response of Capsicum annuum seedlings revealed by non-targeted metabolomic analysis

Abstract

Selenium nanoparticles (SeNPs) are emerging as a novel nanotechnological approach to improve growth, primary and secondary metabolite production, and crop quality. The seedling stage is critical for successful crop establishment and achieving better yields, and SeNPs could improve seedling fitness and metabolism. The impact of SeNPs, previously synthesized with Amphipterygium glaucum extracts and characterized, was evaluated on the seedling stage of serrano pepper (Capsicum annuum). Four weekly foliar applications were made with 0, 2.5, and 10 µM SeNPs. Non-targeted metabolomic analysis was performed by gas chromatography-mass spectrometry (GC-MS) for shoot and root metabolomes. Leaves SPAD values and growth traits (root length, shoot height, stem diameter, and fresh and dry weight) increased with SeNPs application. The highest shoot growth was obtained with 2.5 µM, whereas 10 µM increased root development. Non-targeted metabolomic analysis revealed differences in the abundance of detected metabolites from several families (alpha-hydroxy acids, carboxylic acids, sugar derivatives, fatty acids, terpenes, polyols, phytosterols, and phenolic compounds). Metabolic pathway analysis (MetPA) showed that SeNPs impacted routes related to the L-galactose, ascorbate-aldarate metabolism, fatty acids, citrate cycle, and sugars. SeNPs significantly increased galactopyranose and D-mannitol in shoots and glycerate in roots. These metabolites are involved in cell wall remodeling, stress responses, and energy metabolism. The results contribute to understanding the biological effects of SeNPs and their potential to improve plant growth at 10 µM. Nevertheless, a multi-omics approach combining targeted transcriptomic and metabolomic analyses is needed to fully elucidate the mechanisms underlying the SeNPs effect on plant response to environmental stressors.