Abstract:In order to explore the relationship between the accumulation of flavane-3-ol and the expression of synthesis-related enzymes and key genes in wine grape fruit, the white grape variety Chardonnay grown in Donglu of Helan Mountain was used as material by colorimetric method,high performance liquid chromatography (HPLC) and fluorescence quantitative PCR (FQ-PCR). The accumulation rule of flavane-3-ol monomer and the changes of related enzyme activity and related gene expression pattern during biosynthesis of grape fruit were studied.The results showed that: (1) During the whole fruit development period, the contents of Gallic catechin (GC) and epicatechin gallate (ECG) of flavane-3-ol were much higher than those of catechin (CAT) and epicatechin (EC). The contents of ECG and EC increased at first and then decreased with the fruit growth period, and reached the maximum at 50 days after anthesis, which were 47.69 mg/g and 42.73 mg/g, respectively, while the contents of GC and CAT decreased at first and then increased, and then decreased gradually with fruit ripening. (2) The activities of PAL and ANS related to flavane-3-ol biosynthesis increased at first and then decreased. The activities of F3H, F3"H and CHI peaked at 20 days after anthesis (June 13), and then decreased rapidly, and the activity of DFR increased at first and then decreased, increased again at 50 days after anthesis, and then decreased gradually with fruit ripening.(3)The expression level of structural genes PAL and ANS related to flavane-3-ol biosynthesis was up-regulated at first and then down-regulated with fruit growth period, which was consistent with the change trend of ECG and EC content, while the expression level of F3H, F3"H and CHI was down-regulated at first and then up-regulated. The expression level of DFR was up-regulated at first, then down-regulated, and then up-regulated again with fruit ripening. (4) Correlation analysis showed that the activities of F3H, F3"H and ANS were positively correlated with the content of GC.The expression of F3H and F3"H gene was positively correlated with the content of GC and CAT, and the expression of ANS and PAL gene was positively correlated with the content of ECG and GC. It was found that the synthase and gene expression related to flavane-3-ol biosynthesis affected the accumulation of flavane-3-ol compounds in grape fruit, which further affected the sensory quality of grape wine.