Investigation of Differentially Expressed Proteins Induced by Alteration of Natural Se Uptake with Ultrahigh-Performance Liquid Chromatography Quadrupole Orbitrap Uncovers the Potential Nutritional Value in Se-Enriched Green Tea

Se-enriched green tea, with an increasing consumption, is the shoot of tea plants grown naturally in a seleniferous region. A label-free proteomic strategy based on ultrahigh-performance liquid chromatography quadrupole Orbitrap was applied to characterize and distinguish the difference between the Se-enriched and normal green tea with a total of 283 proteins identified and 264 proteins quantified, in which 96 proteins were observed different. The expressions of 10 proteins were upregulated and 40 proteins were downregulated (p < 0.05) in Se-enriched samples. Gene ontology, Kyoto Encyclopedia of Genes and Genomes pathway, and protein–protein interaction (PPI) network analysis results indicated that these differentially expressed proteins significantly interacted and were involved in secondary metabolites and inflammatory response biological processes. Furthermore, the expression of methyl-jasmonate- and ethylene-related genes changed significantly in Se-enriched green tea, and catalase proteins were employed as the center of the pathway that changed significantly in the PPI network. These results associating with the current knowledge of selenium in soil–plant cycling revealed that organic selenium was synthesized in green tea, which provided novel information on Se assimilation in Camellia sinensis and improved the understanding of Se-enriched green tea as a possible ideal selenium supplement in daily life.