Proteomic changes in association with storage quality of ‘Honeycrisp’ apples after pre and postharvest treatment of 1-MCP

1-Methylcyclopropene (1-MCP) is a well-known ethylene action inhibitor that has been applied to fruit after harvest to maintain fruit quality and extend storage life. Recently, the preharvest application of 1-MCP in a sprayable form has been developed and has demonstrated some beneficial effects to prolong harvest window and improve fruit quality. To gain understanding of molecular mechanisms for 1-MCP treatment, as both pre- and postharvest applications on apples, we conducted a quantitative proteomic experiment employing stable isotope labeling by peptide dimethylation on ‘Honeycrisp’ apples to reveal the significantly changed protein abundance in relationship to fruit quality after preharvest 1-MCP (Harvista™), postharvest 1-MCP treatments as well as their combination. We revealed the treatment affected fruit internal ethylene concentration, fruit quality indices and storage disorders incidence after 7 months of storage at 3 °C. Our quantitative proteomic study identified and quantified more than 600 proteins. Among the identified proteins, 312 proteins were found in common from all treatments, while 141 proteins abundance were changed with regards to preharvest, postharvest and the combination treatments of 1-MCP. We identified a few proteins that were only shown as result of preharvest 1-MCP treatment, while postharvest 1-MCP and in combination with preharvest treatment led to larger number proteins with reduced abundance. These results revealed and confirmed that postharvest 1-MCP and in combination with preharvest 1-MCP treatment affected ethylene biosynthesis, stress resistance, amino acid biosynthesis, antioxidant and redox system metabolisms. Potential metabolic changes resulting from 1-MCP treatment were found, and the efficacy of preharvest 1-MCP treatment was also discussed.