Differential protein profiles of postharvest Gynura bicolor D.C leaf treated by 1-methylcyclopropene and ethephon

Proteins were extracted from G. bicolor that had been treated with 1-methylcyclopropene and ethephon and then stored at room temperature for 1, 3 and 7 days. More than 300 protein spots were detected by 2-DE and 38 differentially abundant spots (P < 0.05) were excised and analysed by using MALDI-TOF/TOF. Thirty-three proteins were finally confidently identified. According to the Clusters of Orthologous Groups of proteins, the proteins identified were classified into those responsible for metabolism (75.8%), information storage and processing (9.1%) and cellular processes and signaling (12.1%). Compared with ethephon and control treatments, 1-methylcyclopropene specifically increased the abundances of superoxide dismutase, peroxidase, carbonic anhydrase, nucleoside diphosphate kinases, glyceraldehyde 3-phosphate dehydrogenase, RuBisCO and ribulose bisphosphate carboxylase/oxygenase activase. 1-Methylcyclopropene protected leaf chloroplast and cells by enhancing stress response and defense, and delayed senescence by inhibiting substance and energy metabolisms. Therefore, 1-methylcyclopropene allowed better self-defense and delayed senescence of G. bicolor leaf.