Abstract
L-ascorbate content was 2-3 μmol gFW-1 in the first 20 days after full bloom (DAFB) in peach fruit. The content then decreased to 0.2 μmol gFW-1 at 92 DAFB and remained till harvest at 112 DAFB. Based on a fluctuation in total amount of L-ascorbate per fruit, four characteristic phases were observed. Feeding of possible precursors suggested L-galactose pathway is dominantly operating. cDNA clones for the last 6 steps were isolated. Northan blot analysis revealed upstream 3 steps (GMPH, GME, GGGT) showed maximum expression at 43 DAFB, whereas downstream 3 steps (GPP, GDH, GLDH) showed two peaks at 21 and 92 DAFB. No clear relationships were observed between biosynthetic gene expression and L-ascorbate content change during fruit development.
