Changes of the proteome in the grape berry skin during ripening

The proteome of the skin of grape a berry cultivar widely cultivated in Northern Italy, such as ‘Barbera’, was studied during the ripening of the berry starting from véraison till ripe. An extraction method suitable to remove interfering compounds was set up. Proteins from cell wall (CWF) and protoplast (PF) fractions were analyzed by bidimensional electrophoresis (2-DE). The LC-ESI-MS/MS approach was used to analyse the PF differentially expressed protein spots. A total of about 1000 spots were detected. Many spots were present in both protoplast and cell wall fractions, suggesting, as previously reported for tissues of other plant organisms, that cell wall is able to bind protein from other cell fractions. The proteome analysis of the PF shows deep changes in protein expression of grape berry skin during ripening, which involve different metabolisms that are known to be related to berry ripening.