Fig. 3

Soluble proteins, potato multicystatin (PMC) and protease activity in tubers of line K52, line K53 and control line K stored for different periods at 4 °C. a Diagram showing the position of tuber ‘edge’ and ‘flesh’ tissues collected for the analyses. b Total soluble proteins in crude protein extracts of flesh tissue after storage for 0, 36 or 48 weeks. Data are expressed as percentages on a fresh weight basis. c Immunodetection of PMC in crude protein extracts of tuber edge and flesh tissues upon harvesting (0 week) or after storage for 48 weeks. Densitometric data are expressed for stored tubers relative to initial levels at time 0 (arbitrary value of 1.0). PMC on the immunoblot image corresponds to PMC purified from tuber skin. d Gelatin hydrolysis zymogram for the main proteases of flesh tissue (P1, P2 and P3) in line K and line K52 tubers after storage for 48 weeks. +rOCI, crude extract incubated with recombinant OCI expressed in E. coli before electrophoretic migration. Each bar on panels (b) and (c) is the mean of six biological (tuber) replicates ± se. Identical volumes of crude extract were loaded in each well on panels (c) and (d). For each time point or tissue type, bars with the same letter are not significantly different (post-anova Tukey’s test ; P > 0.05)