Comparative analysis of the dynamic proteomic profiles in berry skin between red and white grapes (Vitis vinifera L.) during fruit coloration

The aim of this study was to deepen our understanding of the proteomic profiles related to skin coloration at the whole proteome level through the analysis of multiple protein spots. A comparative proteomics analysis was conducted on the berry skins of red and white progeny derived from a single cross, 'Jingxiu' (red) × 'Muscat of Alexandria' (white), to minimize genetic background differences. Among the 1000-1800 spots assessed, the levels of 57, 70 and 26 proteins were lower in the skins of white progeny, compared to the skins of red progeny at about two weeks before veraison, at veraison and at maturity, respectively. Alternatively, the levels of 54, 50 and 23 proteins were higher at about two weeks before veraison, at veraison and at maturity, respectively. The levels of proteins involved in anthocyanin biosynthesis, especially UFGT and AOMT, were lower in the skins of white progeny at veraison and at maturity, and the levels of most proteins involved in amino acid metabolism were found to be lower before veraison. Almost all differentially accumulated proteins involved in energy production were found before and at veraison, while there was no difference detected in the levels of glycolysis, tricarboxylic acid cycle and photosynthesis between the skins of red and white progeny. The differential accumulation of enzyme proteins involved in anthocyanin synthesis had a decisive influence on the different skin colorization of red and white progeny. Many proteins related to metabolism and energy production were also differentially accumulated. In addition, many differences in the skin proteomes of white and red progeny were apparent before veraison, i.e. before skins developed coloration.