    1.1.1.316 | metabolism |
L-ascorbic acid (AsA) biosynthesis through the L-galactose pathway supplemented by D-galacturonic acid pathway and AsA recycling collectively contributes to accumulating and remaining higher AsA level in kiwifruit cv. White during postharvest. L-Galactose dehydrogenase (GalDH) activity and relative expressions of the genes encoding GDP-D-mannose diphosphorylase (GMP), L-galactose-1-P phosphatase (GPP), GDP-L-galactose phosphorylase (GGP), GalDH and GalUR are important for regulation of AsA biosynthesis. The genes including GMP, GME, GGP, GPP, GalDH, and GalLDH involve in L-galactose pathway. The activity and expression of dehydroascorbate reductase (DHAR) are primarily responsible for regulation of AsA recycling in kiwifruit cv. White during postharvest. Changes in activities of enzymes involved in AsA metabolism in the fruit during storage, quantitative real-time PCR expression analysis. GalDH activity is positively correlated with AsA content. GalLDH activity maintains a relatively steady level for the first 17 days of fruit storage, and then decreases a lowest level at 21 days of storage. The expression of GalDH increases sharply during the first 9 days, and then gradually increases to about 4times higher level compared to the initial level whereas, GalLDH is stably expressed with a slight fluctuation during storage |
763588 |
