Abstract: 【Objective】The aim of this study was to ascertain the effect of different fruit color bags on grape anthocyanin biosynthesis and preliminarily clarify the mechanism, providing theoretical guidance for the development of grape fruit bags. 【Method】The experimental materials were five-year-old vines of ‘Kyoho’ grape using ‘Beta’ as rootstock, bagged with red, green, blue and white fruit paper bags 30 days after fruit setting, respectively, and no bagging as control. The berries were sampled every eight days from bagging to full mature stage. The fruit bag transmission spectrum analysis was tested with StellarNet^® Black-Comet Spectrometers. Anthocyanin content in fruit peel was measured by HPLC. The expression of anthocyanin biosynthesis pathway structural genes VvCHS, VvLDOX, VvUFGT, and regulatory gene VvmybA1 and light signal transcription factor VvHY5 were analyzed by real-time PCR. 【Result】Red bag, green bag and blue bag had selective permeability in red, green and blue band, while white bag had no selective permeability for light quality. Different color fruit bags significantly affected grape anthocyanin biosynthesis. Red bag, green bag and blue bag treatments significantly delayed grape variation, and delayed anthocyanin accumulation, but anthocyanin contents in blue bag and white bag treatments were higher than the control at last. RT-PCR analysis showed that the expression of VvmybA1, VvCHS, VvLDOX and VvUFGT increased first and then decreased, which was consistent with anthocyanin accumulation. Different color fruit bag treatments delayed the expression increase of VvmybA1, VvCHS, VvLDOX and VvUFGT at the early stage of fruit ripening and also delayed their expression decrease at the late stage of fruit ripening. Their expression contents were higher in control and white bag treatment, followed by blue bag, green bag and red bag treatments before the expression peaks, while after the expression peaks, their expressions in control were lower than blue bag, white bag, green bag and red bag treatments. In anthocyanin rapid accumulation period and the late stage of fruit ripening, VvHY5 had two expression peaks, which was consistent with the variation patterns of anthocyanin accumulation and the expression of VvmybA1 during fruit ripening. The induction ability of different color fruit bags on VvHY5 expression was different, like that the blue paper bag was the strongest and the red paper bag was the worst.【Conclusion】Blue paper bag is of benefit to grape anthocyanin biosynthesis, while red paper bag is poor. The regulation of anthocyanin accumulation in grape by different color fruit bags is probably through the light signal transcription factor VvHY5, and then regulated the expression of anthocyanin biosynthesis pathway regulatory gene VvmybA1 and structural genes VvCHS, VvLDOX and VvUFGT.

Key words: grape, fruit bagging, light quality, anthocyanin, gene expression