Phenylalanine Induces Mango Fruit Resistance Against Chilling Injuries During Storage at Suboptimal Temperature.

Cold is the best means of prolonging fruit storage. However, tropical fruit are susceptible to cold storage. The mode of action of mango fruit tolerance to suboptimal cold temperature of 7 or 10 degrees C after postharvest appli-cation of 8 mM phenylalanine was investigated using transcriptomic and metabolomic analyses of mango fruit during suboptimal cold storage. Phenylalanine-treated fruit had less chilling injuries-black spot and pitting electrolyte leakage,-and reduced decay after suboptimal cold storage. Phenylalanine treatment induced genes related to plant-pathogen interactions, plant hormone signal transduction, and the phenylpropanoid pathway, increasing the levels of the flavonoids quercetin and kaempferol glycosides and anthocyanins, and antioxidant content. Reduced oxidation led to lower lipid peroxidation, and a reduction in fatty acid-degradation products, e. g., volatile aldehydes. Treatment with phenylalanine, therefore, enhances chilling tolerance of mango fruit through regulation of metabolic and defense-related pathways, maintaining high levels of flavonoids, and an-tioxidants enzyme activity, and reducing H2O2 content, lipid peroxidation, and volatile aldehydes.