| Muscat grape(Vitis vinifera L.cv.Muscat Hamburg) provided by Beijing Agricultural collage's grape germplasm nursery was studied in this research. Muscat grape belonging to Eurasia and was led into Yantai Shandong Province by American missionary-Ni shi in 1871 for the first time, and in 1892 for the second time. Muscat grape is one of the most widely distributed species in our country and nearly every grape origin had cultivation of it. This breed has the features as following displayed:middle-late in maturity, moderate in tree vigor, high quality in secondary outcome, high yield quality, fruit is small, taste sweet and take on a rose fragrance, flesh is firm and easy to transport or long-storage. Above all, this is a cultivar can be used both for eat and wine-making.The experiment was carried on between the year 2008 and 2010 which contained two parts. The first part mainly researched the dynamics of fruit growth, fruit quality index and ABA content using the fruit collected every 7 days after 2 weeks of flowering. And also the different expression of 9-cis expoxy carotenoid dioxygenase (NCED), cytochrome P450-dioxygenase (CYP), glycosyltransferase (GT) and (3-glucose esterase using fruit collected between 7 and 11 weeks after flowering. The second part mainly studied effects of different concentrations (100 mg·kg-1 and 250 mg·kg-1, the field-grown as control) of ABA treatment on fruit coloring and quality using fruit treated 7 days. The results were as follows:1. With smear of ABA can be beneficial to improve color index of grape berry. With the increasing of smear concentration, color index were improved. Determination results of grape berries suggest:ABA improved average single particle weight of grape berry, increased the sugar content. Treatment effect was the best with the concentration of 250 mg·kg-1 of ABA, and 100 mg·kg-1 of ABA took the second place.2. The trend of vertical and horizontal diameter of grape berry was almost the same, and this was divided into fast-slow-fast three periods. The soluble sugars are mainly glucose,fructose and sucrose, glucose and fructose have the same changing trend which increase from the early veraison to full maturity. Fructose has a more increase amplitude than glucose. Sucrose content is less, which has a gentle increasing trend and the increase amplitude is small. At and after veraison, pH value increases rapidly, having matching and opposite changing trend with total acid content. Similarly, ABA content increases rapidly coupling with veraison, and having a peak at two weeks after veraison, then declining until complete ripening.we can conclude that fructose plays an important part on the sweet increasing during fruit ripening. ABA is closely related with the veraison time of fruit.3. The RNA was extracted from the grape berry, then inversed into cDNA. We designed degenerate primers of NCED,CYP. GT. BG, and amplified 4 gene fragments and sequencing. Based on gene fragments of four genes, we designed fluorescence primer to determinate expression changes of four genes 7 to 11 weeks after flowering. The results were as follows. (1) the expression level of VvNCED1 gene was very high during 7-8 weeks after flowering, followed by a rapid decline to its lowest point, and then increased a little. (2) the expression level of VvBG1 had two quick increasing. With the onset of fruit ripening, the first increasing began 7-8 weeks after flowering. The second increasing began 9-10weeks after flowering, which has a quick increasing. (3)The expression level of VvGT1 increased quickly to the maximum at 8 weeks after flowering, and then declined quickly. The expression level of VvGTl 9-11 weeks after flowering was higher than that of 7 weeks after flowering. (4) The expression level of VvCYP1 increased to its maximum from 7 to 9 weeks after flowering, and then declined to its minimum in the following two weeks. The expression level of VvCYP1 10-11 weeks after flowering was less than that of 7 week after flowering. Given that the ABA continual rising during the onset of grape berry ripening, it is considered that, before the onset of berry ripening. The ABA accumulation is attributed to high mRNA expression level of VvNCED1; after the onset of berry ripening, ABA accumulation is attributed to high mRNA expression level of VvBG1. both VvGTl and VvCYP1 are in higher expression level 8-9weeks after flowering, which is in accordance with lower content of ABA.4. Bioinformatics analysis was performed to VvBG1 gene. The molecular weight was 57KD, the pI were predicted as 6.24. Confirmation prediction was like a barrel.
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