Proteins were considered differentially expressed when they showed a 1.2-fold change at the p < 0.05 level in the different samples (0 h PG vs. −72 h PG, 72 h PG vs. 0 h PG and 72 h PG vs. −72 h PG). A total of 612 proteins were differentially expressed between the 0 h PG and −72 h PG samples (Fig. 1, Table S1), with 276 up-regulated and 336 down-regulated proteins. Further GO classification analysis of these proteins was performed. For biological processes, 24%, 19% and 10% of the differentially expressed proteins were correlated with metabolic processes, cellular processes and developmental processes respectively. For molecular function, 44% and 40% of the differentially expressed proteins were associated with binding and catalytic activity respectively. For cellular components, 43% and 27% were related to cells and organelles, respectively (Fig. 2).