Methyl salicylate induces endogenous jasmonic acid and salicylic acid in 'Nam Dok Mai' mango to maintain postharvest ripening and quality

Abstract

Salicylic acid (SA) and jasmonic acid (JA) are indispensable phytohormones whose interaction influences the ripening process in plants. Methyl salicylate (MeSA) and methyl jasmonate (MeJA) have been utilized to elevate the endogenous levels of SA and JA in horticultural products after harvest. However, their ability to preserve mango is uncertain. Individually and combined effects of exogenous MeSA and MeJA on mango ripening quality were investigated. 'Nam Dok Mai' mangoes were fumigated with MeSA, MeJA, and MeSA plus MeJA (MeSAJA) prior to storage for 6 d at 25 °C and 80–85% relative humidity (RH). Fruit ripening attributes, respiration rate, ethylene (ET) production, total phenolics (TP), and malondialdehyde (MDA) were assessed. Endogenous SA and JA levels were measured, as were the activities of lipoxygenase (LOX) and phenylalanine ammonia-lyase (PAL), and the expression of related genes MiPAL, MiICS, and MiLOX. Individual application of MeSA or MeJA preserved the mango quality by reducing ET production, respiration rate, and MDA levels while raising TP shortly after treatment. The ripening quality mirrored the induced SA and JA levels and correlated with the high expression of biosynthetic-related genes (MiPAL, MiICS, and MiLOX). Individual treatments stimulated SA and JA biosynthesis, demonstrating that these phytohormones are functionally connected and interdependent. When combined, MeSAJA caused a tradeoff response and distinct phenotypic outcomes compared to the individual treatments. As a result, MeSA fumigation is a practical method for preserving mango quality after harvest.