Identification of mRNAs with enhanced expression in ripening strawberry fruit using PCR differential display

Fruit ripening is a complex development process that involves specific changes in gene expression and cellular metabolism. In climacteric fruits these events are coordinated by the gaseous hormone ethylene, which is synthesized autocatalytically in the early stages of ripening. Nonclimacteric fruits do not synthesize or respond to ethylene in this manner, yet undergo many of the same physiological and biochemical changes associated with the production of a ripe fruit. To gain insight into the molecular determinants that are unique to nonclimacteric fruite ripening, we examined mRNA populations in ripening strawberry fruit using the PCR differential display technique. Five mRNAs with ripening-enhanced expression were identified using this approach. Three of the mRNAs appear to be fruit-specific, with little or no expression detected in vegetative tissues. Sequence analysis of cDNA clones revealed positive identities for three of the five mRNAs based on homology to know proteins. These results indicate that the differential display technique can be a useful tool to study fruit ripening and other developmental processes at the RNA level.