Abscisic acid treatment prolongs the postharvest life of strawberry fruit by regulating sucrose and cell wall metabolism

After harvesting, strawberry fruit (Fragaria x ananassa, Duch.) are highly susceptible to deterioration in appearance, firmness and quality, all of which limit storage and transportation life. To increase storage life and reduce losses of strawberry, a pre-storage spray treatment of ripe fruit with relatively low concentrations (100 mu M) of abscisic acid (ABA) were used. ABA treatment increased the concentration of the soluble sugars sucrose and glucose, and modified the expression of genes involved in sugar metabolism with a substantial reduction in the mRNA abundance of a highly-expressed neutral invertase. ABA treatment also suppressed the expression of polygalacturonase and a pectate lyase that have been shown to be involved in strawberry fruit softening. Corresponding improvements in middle lamella structure and intercellular adhesion were observed using microscopy. The results show that ABA extended the postharvest life of strawberries by increasing content of soluble sugars and maintaining integrity of cell wall.