Proteomic changes in mango fruit peel associated with chilling injury tolerance induced by quarantine hot water treatment

Abstract

The aim of this study was to identify proteins associated with the chilling injury (CI) tolerance induced by hot water treatment (HWT) in ‘Keitt’ mango fruit. A comparative proteomic analysis was performed between fruit with HWT (46.1 °C, 90 min) and non-treated (Control) after cold storage (0 and 20 d at 5 °C) and ripening (7 d at 21 °C); the expression of genes encoding some selected proteins was analyzed by real-time PCR. Twenty-six proteins were differentially expressed after HWT, 36 after 20 days of cold storage and 33 after ripening. Polypeptides with higher accumulation in HWT fruit included eleven heat shock proteins (HSPs), eight enzymes of the energetic metabolism (ACO1, ACO2, GAPDH-1, GAPDH-2, ADH, SDH, ADK, and ACAA) and seven of the secondary metabolism (PAL, CHS, CHI, PDS, HPPD, IsoCH, and PPO), four antioxidant enzymes (CAT, POD, Prx, and APX,), four proteins involved in hormone metabolism (P-gp2, ARF, ERF, and GA3ox1), two pathogenesis-related proteins (β-Glu and 2 s alb), four enzymes of cell wall metabolism (EGase, β-Gal, Rab11 and αMan), and three proteins involved in chloroplast metabolism (RuBisCo, PDX1, and rpl2). Non-treated fruit showed higher accumulation of polyphenol oxidase and alcohol dehydrogenase, suggesting a higher oxidation of phenols and lower efficiency in energy production. The CI tolerance induced by the quarantine HWT in mango fruit appears to be associated with the prevention of protein denaturation, the maintenance of the membrane functionality and energy efficiency, the activation of antioxidant and defense systems, the preservation of cell wall metabolism, and the synthesis of secondary metabolites.