Preharvest sodium selenite treatment improves postharvest storage quality of purple leaf mustard

Both selenium (Se) and anthocyanins are essential nutrients for maintaining human health. However, it remains largely unknown how preharvest Se biofortification influences anthocyanin metabolism in harvested vegetable during postharvest storage. This study investigated the effects of Se pretreatment on storage quality of purple leaf mustard. Se preharvest duration significantly affected leaf mustard growth, with 7-d being optimal. Se pretreatment, reduced weight loss rate by 25.05% compared to the control at 9 d, maintained superior color values, and preserved higher chlorophyll contents exhibiting 5.51% to 18.78% higher Fv/Fm values during storage. Additionally, Se pretreatment enhanced the activity and gene expression of three antioxidant enzymes (POD, CAT, and APX), while reduced H 2 O 2 and MDA levels by 8.16% to 24.13% and 3.40% to 23.15%, respectively. Furthermore, Se pretreatment decreased the activities and/or gene expression of laccase and polyphenol oxidase, while simultaneously increasing phenylalanine ammonia-lyase activity and the related genes expression. These changes delayed the decline in total anthocyanin and phenolic contents, suggesting that Se pretreatment both stimulates anthocyanin biosynthesis and inhibits its degradation. Moreover, Se pretreatment changed the abundances of 14 volatile compounds, including dominant component propyl isothiocyanate, before or after storage. Transcriptomic analysis revealed that differentially expressed genes (DEGs) were significantly enriched in the phenylpropanoid biosynthesis pathway and several lipid metabolism pathways, especially among the DEGs upregulated by Se pretreatment. Overall, these results suggest that preharvest Se pretreatment improves storage quality of purple leaf mustard, providing valuable insights into simultaneously enriching Se while maintaining anthocyanins in fresh vegetable. • Preharvest Se enrichment enhances the quality of purple leaf mustard. • Preharvest Se enrichment regulates both anthocyanin biosynthesis and degradation. • Preharvest Se enrichment affects volatiles of cold-stored leaf mustard. • Preharvest Se enrichment promotes fatty acid metabolism.