Oligogalacturonide-accelerated healing of mechanical wounding in tomato fruit requires calcium-dependent systemic acquired resistance.

• Application of OGs accelerated healing of mechanical wounds in tomato fruit. • Application of OGs increased SAR hallmark gene SlPR1 expression and PAL activity. • Inhibition of Ca2+ signaling inhibited OG-elicited healing of mechanical wounds. • Callose deposition around the mechanical wound was elicited by OG application. • Application of OGs decreased SlPG2 expression and retarded fruit softening. Mechanical wounding causes significant economic losses of fresh produce due to accelerated senescence and spoilage as well as loss of nutritional value. Here, pre-application of oligogalacturonides (OGs) enzymatically hydrolyzed from apple pectin effectively reduced the healing times of mechanical wounds from>24 h in mock groups to 12 h, and the Botrytis cinerea infection rate was reduced from 37.5% to 12.5%. OGs accordingly increased callose deposition; SlPR1, SlPAL and SlHCT gene expression; and phenylalanine ammonia-lyase (PAL) activity around the wounds. Inhibition of Ca2+ signaling using the inhibitor Ruthenium Red markedly inhibited OG accelerated healing of mechanical wounding on fruit. SlPG2, SlEXP1 , and SlCEL2 mRNAs accumulation was reduced in OG-elicited tomato fruit compared to water-treated fruit with subsequent retardation of the fruit softening during ripening. These results indicated that apple pectin OGs accelerate wound healing and inhibit fruit softening by activating calcium signaling in tomato fruits during postharvest storage. [ABSTRACT FROM AUTHOR]