Abstract:

Light-red-skinned‘Muscat Rouge’grape is mutation of white-skinned‘Muscat Blanc’. Both of them are high-quality grapewine cultivars. However，the mechanism of the color mutation in ‘Muscat Rouge’has not been elucidated so far. In this study，12 SSR markers were applied to analyze the relationship of these two cultivars firstly. The results revealed that there was not amplification difference between them. The VvmybA1 gene sequence analysis results revealed that‘Muscat Blanc’harbored only VvmybA1a at the VvmybA1 locus，both VvmybA1a and VvmybA1b alleles in‘Muscat Rouge’. The qRT-PCR results indicated that the higher levels of expression of VvmybA1 gene，3-O-glucosyltransferase（UFGT），flavanone 3',5'-hydroxylase（F3'5'H），chalcone synthase（CHS），O-methyltransferase（OMT），and glutathione-S-transferase（GST）were detected in‘Muscat Rouge’and‘Pinot Noir’. The elementary composition of the anthocyanin profiles were analyzed using high-performance liquid chromatography and electrospray ionization mass spectrometry（HPLC–ESI–MS/MS），revealing divergent chemical profiles.‘Muscat Rouge’and‘Pinot Noir’both showed higher abundance of Cyanidin 3-O-glucoside（CyG），Cyanidin 3-O-glucoside-5-O-glucoside（Cy2G），Delphinidin 3-O-glucoside（DpG），Malvidin 3-O-glucoside（MvG），Peonidin 3-O-glucoside（PnG），Petunidin 3-O-glucoside（PtG）than ‘Muscat Blanc’and‘Pinot Blanc’. These results suggested that the red-skinned‘Muscat Rouge’phenotype is the re-mutation of VvmybA1a alleleto VvmybA1b gene.

Key words: grape, berry skin, VvmybA1, gene mutation