In conclusion, when exogenously supplied, under field conditions, and at proper concentrations and growth stages, JAs enhance their own biosynthetic pathway. Transcriptome profiling of JA-treated fruit confirms the down-regulation of crucial ripening-related genes, in agreement with the inhibition of ethylene production, and the up-regulation of stress/defence-related genes. Taken together these results may suggest that, in JA-treated fruit, resources are diverted from growth and ripening, consistent with a trade-off between development and defence (Schmidt and Baldwin, 2006). Finally, most experimental outcomes derive from studies conducted in simple and controlled environments (in vitro, growth chambers, or greenhouses), and often these result in partially overlapping, but definitely not coinciding, effects. The present information, arising from JA application in a field environment, where plants have to cope with multiple biotic and abiotic elicitors, may open up new perspectives for the use of JAs in the control of fruit ripening and defence.