Abstract
Although lychee peel extract (LPE) is rich in bioactive compounds, its potential for postharvest fruit preservation remains unexplored. We hypothesised that LPE would act synergistically with chitosan (CH) to delay mango ripening by simultaneously modulating cell wall integrity, pigment metabolism, and hormone signaling pathways. Here, we demonstrate that chitosan combined with lychee peel extract (CHL) delays mango ripening through a multi-targeted mechanism. Specifically, CHL outperformed chitosan alone by significantly suppressing peel yellowing, maintaining fruit firmness, and reducing decay over 12 days of storage. Integrated transcriptomic and metabolomic analyses revealed that LPE reprogrammed ripening-associated pathways by (1) upregulating cell wall remodeling genes (CSLE1, XTH23) to stabilize pectin architecture, (2) retaining chlorophyll via suppressed CRTISO and PSY (carotenoid synthesis) and enhanced CHLP (chlorophyll biosynthesis), and (3) decoupling sugar-acid dynamics through γ-aminobutyric acid (GABA) and succinic acid accumulation. Notably, LPE attenuated ethylene-auxin- abscisic acid (ABA) crosstalk by downregulating ripening-specific transcription factors (ERF003, bZIPs) while activating stress-responsive WRKYs. These findings establish LPE as a sustainable alternative to synthetic preservatives, leveraging agricultural byproducts for eco-friendly fruit preservation.