Ethylene plays an important role in the softening and sucrose metabolism of blueberries postharvest.

We studied the effects of ethylene on softening and sucrose metabolism in postharvest blueberry fruit by examining the responses of fruit firmness, cell wall polysaccharides, cell wall enzymes, four key genes of cell wall degradation and metabolism, enzyme activities, and five key genes of sucrose metabolism to exogenous ethylene treatments. Ethylene was found to accelerate blueberry softening, as it promoted the degradation of pectin and expression of pectinesterase (PE) and polygalacturonase (PG). Sucrose catabolism was accelerated with fruit softening, while sucrose content, sucrose phosphate synthase (SPS) activity were positively correlated with the loss of fruit firmness. Exogenous ethylene treatments promoted sucrose metabolism by inhibiting the expression of VcSPS1 and VcNIN2 and stimulating the expression of VcSS1 and VcCWINV1. These results indicate that ethylene plays an important role in fruit softening and sucrose metabolism of blueberry at 20 °C, and there may be a link between sucrose metabolism and fruit softening.