Pb4CL2 Inducing Lignin Accumulation in Superficial Scald ‘Chili’ (Pyrus bretschneideri) Pear Fruit

Superficial scald of pear fruit is a physiological disorder that easily occurs during cold storage and seriously affects pear eating quality and commodity value. It is important to study the mechanism of superficial scald disorder. Our previous study reported that the incidence of superficial scald of calcium chloride (CaCl2)-treated pear fruit during storage was significantly lower than that of untreated fruit. In this study, we found that the accumulation of lignin in CaCl2-treated fruit was significantly lower than that of untreated fruit. The expression of the Pb4CL2 gene in the lignin synthesis pathway was downregulated in the CaCl2-treated fruit. The lignification level of the fruit overexpressing Pb4CL2 was significantly higher than that of the empty vector fruit. Therefore, we speculate that downregulation of Pb4CL2 after CaCl2 treatment plays an important role in CaCl2 inhibiting superficial scald disorder by affecting lignin accumulation in pear fruit.