Difference in activity and gene expression of pectin-degrading enzymes during softening process in two cultivars of Chinese pear fruit

Abstract

Cell wall pectin-related physiological and molecular properties changes in two different cultivars of Chinese pear fruit, ‘Jingbaili’ and ‘Yali’, were investigated in this study. ‘Jingbaili’ pear fruit, which softened quickly, showed higher pectin fracture solubilization, while ‘Yali’ pear fruit, which maintained a firm texture, presented little change in the content of pectin fractions during storage. The activities of PG, β-GAL and α-ARF that involved in fruit softening were significantly higher in ‘Jingbaili’ pear fruit compared to ‘Yali’ pear fruit. Furthermore, the mRNA accumulation of the genes, such as PG1, PG2, GAL4, ARF1 and ARF2 that encoded above-mentioned cell wall hydrolase dramatically increased in ‘Jingbaili’ pear fruit during fruit softening. Thus, we concluded that ‘Jingbaili’ pear fruit may be more prone to degradation in cell wall pectin compared to ‘Yali’ pear fruit, suggesting that their different softening patterns determine the different modes of cell wall pectin disassembly between these two different types of Chinese pear fruit.