Fig. 4
Kiwifruit protein profile gel maps as affected by 1-MCP and O3 treatments or exogenous ethylene exposure. Representative 2DE-protein spots of pericarp flesh tissue of control kiwifruit (a). Equal amounts (50 μg) of total soluble protein extracts were loaded in each gel. The functional categories of the kiwifruit proteins that identified are shown with color codes (b). Enlarged 2DΕ-gel regions exhibiting differences in protein spot abundance as in plate (a) for control and 1-MCP-, O3- and 1-MCP + O3-treated kiwifruit that were cold-stored (0 °C, 90% RH) for 6 months plus 8 d at 20 °C (c). Zoom-in areas of the 2DΕ-gel maps exhibiting differences in protein spot abundance of kiwifruit exposed or not to exogenous ethylene (ETH) (d). 2DE-maps created three times for a minimum of three independent extractions that each corresponded to a biological replication per treatment. Representative protein spots are listed in Additional file 4: Table S1. Black, red and blue arrows indicate identified proteins that remained unchanged, increased or decreased in abundance, respectively, in control kiwifruit or the ones treated with 1-MCP, O3 and 1-MCP + O3 and exposed or not to exogenous ethylene. 2DΕ-protein relative abundance of polygalacturonase (PG, Spot 3702, Additional file 11: Table S5) and PG expression patterns by real-time RT-qPCR in control and O3-treated kiwifruit under external ethylene (ETH) or ambient conditions (e). Data (mean ± SE) of three biological replications. Asterisks (*) indicate statistically significant differences between groups (O3 vs. control or O3-ETH vs. O3)