# Lychee peel extract and chitosan synergistically delay mango ripening: Molecular insights

## TL;DR

Lychee peel extract combined with chitosan helps preserve mangoes longer by affecting cell walls, pigments, and hormones.

## Contribution

Lychee peel extract synergizes with chitosan to delay mango ripening through multi-targeted molecular mechanisms.

## Key findings

- CHL significantly suppressed peel yellowing and decay while maintaining fruit firmness.
- LPE modulated pigment metabolism by suppressing carotenoid synthesis and enhancing chlorophyll biosynthesis.
- LPE altered hormone signaling by downregulating ripening-specific transcription factors and activating stress-responsive genes.

## 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.

•LPE-chitosan coating synergistically delayed mango ripening and reduced decay.•Improved fruit firmness was linked to cell wall gene upregulation.•Peel color retention was associated with modulated pigment metabolism pathways.•Metabolic shifts toward organic acid accumulation helped maintain fruit acidity.•Extended shelf life was correlated with altered plant hormone signaling crosstalk.

LPE-chitosan coating synergistically delayed mango ripening and reduced decay.

Improved fruit firmness was linked to cell wall gene upregulation.

Peel color retention was associated with modulated pigment metabolism pathways.

Metabolic shifts toward organic acid accumulation helped maintain fruit acidity.

Extended shelf life was correlated with altered plant hormone signaling crosstalk.