The discovery of 1-methylcyclopropene (1-MCP) as an inhibitor of ethylene action has provided an important tool in understanding fruit ripening physiology as shown by the huge amount of 1-MCPtargeted research carried out particularly, although not exclusively, in postharvest science. It has been clearly demonstrated that 1-MCP is able to improve the handling procedures and storage life of a number of commodities. In fact, 1-MCP can reduce ethylene biosynthesis, respiration, softening color changes, aroma production, and the occurrence of physiological disorders and stress responses. These effects are related to the interference of 1-MCP on the ethylene receptor functioning (1-MCP-receptor binding is irreversible) and for some of them in their transcription rate and protein stability. However, the efficacy of this olefin strongly depends upon the concentration used, the species and variety, storage condition and duration, and maturity of the fruit before the 1-MCP application. A marked effect of 1-MCP occurs in climacteric fruit, although studies carried out in nonclimacteric fruit demonstrates that this olefin can also alter specific ripening processes in these fruit types. The research results obtained by applying 1-MCP confirms the very well-known ethylene-dependent ripening processes as well as allowed the identification of previously unrecognized responses to ethylene. Molecular studies performed on 1-MCP-treated fruit have provided new insights into the role of ethylene in the regulation (mainly at the transcriptional and, to a lesser extent, at the translational level) of genes involved in ripening processes such as cell wall metabolism, and pigment and aromatic compound biosynthesis, as well as the signal transduction pathway of the gaseous hormone. Postharvest use of 1-MCP has improved our understanding of ethylene effects on the development of physiological disorders (e.g. superficial scald, internal breakdown) and stress responses (e.g. chilling injury and pathogen attack). This extensive information base will be extremely useful in the future development of innovative and more efficient postharvest strategies where the effect of 1-MCP could be enhanced by the concomitant applications of other storage technologies.
Keywords: antioxidants, aromas, ethylene, firmness, physiological disorders, pigmentation, receptors