LED irradiation treatments affect postharvest ripening processes that improve the quality of pepino (Solanum muricatum) fruit

Pepino ( Solanum muricatum ) fruit are harvested early to reduce postharvest losses but as a result often ripen incompletely. Changes in appearance and quality parameters, transcriptomics, and metabolomic analyses were utilized to investigate how red, white, or blue LED irradiation treatments (100 μmol m −2 s −1 ) promote the ripening of pepino. Results indicated that the different LED irradiation treatments promoted the expression of genes and the abundance of metabolites associated with carotenoid, flavonoid, and anthocyanin biosynthesis, which facilitated fruit color development. LED irradiation treatments upregulated the expression of genes involved in glycolysis, as well as starch and sucrose metabolism, while they downregulated genes associated with gluconeogenesis. LED irradiation treatments also activated many of the genes involved in cell wall-degradation, ethylene biosynthesis, and signaling. The LED irradiation treatments also upregulated genes that function in fatty acid metabolism, which contributes to the characteristic aroma of ripening pepino. Our study provides information on the mechanisms by which LED light technology regulates the physiological and metabolic processes associated with the postharvest ripening of pepino. A schematic model illustrating the molecular mechanisms by which red, white, and blue LED light treatments at 100 μmol m −2 s −1 contribute to changes in ripening processes during the postharvest storage of pepino fruit. The model is based on a comprehensive analysis of physiological, biochemical, transcriptomic, and metabolomic data. Red circles and rectangular frames indicate the upregulated DEGs and DAMs with increased abundance, while green circles and rectangular frames indicate downregulated DEGs and DAMs with decreased abundance. • Red, white, and blue LED light treatments promote ripening of pepino ( Solanum muricatum ). • LED exposure enhances fruit coloration, softening, sugar accumulation, and aroma. • Transcriptomic and metabolomic analyses reveal pathways regulated by LED light. • LED treatments activate cell wall-degrading enzymes, accelerating fruit softening. • Findings provide insights into LED light technology for postharvest quality improvement.