Increasing the crop quality through enhancement of plant health is challenging task. In this study, nano-selenium (nano-Se) were sprayed on pepper leaves, and the pepper components were compared with that of selenite. It's found that nano-Se (20 mg/L) resulted in greater performance on plant heath. It increased chlorophyll and soluble sugar levels, which could activate phenylpropane and branched-chain fatty acid pathways, as well as AT3-related enzymes and genes expressions. These dead to enhancement for synthesis of capsaicinoids, flavonoids, and total phenols. The nano-Se treatment also significantly promoted expression of phyto-hormones synthesis genes, consequently increasing jasmonic, abscisic and salicylic acid levels. Proline pathway-related compounds were increased, which could decrease malondialdehyde and hydroxyl radical levels in crops. In conclusion, this study show that nano-Se activated capsaicinoid pathways through enhancing photosynthesis and raising soluble sugar levels. The capsaicinoid contents in peppers were then increased, consequently promoting the accumulation of secondary metabolites and antioxidants. KEYWORDS: nano-selenium, pepper, capsaicinoids, phytohormones, nutrients, antioxidant capacity.
Nano-selenium foliar applications enhance the nutrient quality of pepper by activating the capsaicinoid synthetic pathway.