关键词: 桃, 早熟, 芽变, 蔗糖, 苹果酸, RNA-seq

Abstract: In order to reveal the mechanism of differences in soluble sugar and organic acid accumulation in fruit development between‘Kurakato Wase’peach and its early-ripening mutant，the difference content of soluble sugar and organic acid involving in the development of peach fruit were studied in‘Kurakato Wase’peach and its early-ripening mutant. During fruit development，the expression profiles of sucrose and malic acid metabolism-related genes were analyzed. The expression of relevant genes with obvious trends were validated by qRT-PCR. The result showed that the content changes of glucose， fructose，sucrose，sorbitol，citric acid，malic acid and shikimic acid of both were basically consistent during fruit development，and the contents of malic acid and soluble sugars had no significant differences when ripened between‘Kurakato Wase’peach and its early-ripening mutant. The contents of sucrose were higher than those of‘Kurakato Wase’peach，and the content of malic acid were lower than those of‘Kurakato Wase’peach in 59 and 71 days after flowering. RNA-seq data and correlation analysis showed that the differences of sucrose content were mainly affected by PpSUS1，PpSPS1，PpINV2 and PpTMT1-1，the expression levels of PpSUS1 and PpTMT1-1 increased gradually during fruit development，which is consistent with the change trend of sucrose content between‘Kurakato Wase’peach and its early-ripening mutant. The expression of PpSPS1 is positive correlation with sucrose. The difference of malic acid content was affected by PpMDH1-2 and PpNADP-ME1. The expression of PpMDH1-2 reduced gradually during fruit development. The expression of PpMDH1-2 was notably lower than‘Kurakato Wase’peach in 59 and 71 days after flowering. PpPEPCK1，PpPEPCK2 paly auxiliary roles for the content accumulation of malic acid.

Key words: peach, early-ripening mutant, sucrose, malic acid, RNA-seq