IDENTIFICATION OF MESSENGER-RNAS WITH ENHANCED EXPRESSION IN RIPENINGSTRAWBERRY FRUIT USING POLYMERASE CHAIN-REACTION DIFFERENTIAL DISPLAY

Fruit ripening is a complex developmental process that involves specif ic changes in gene expression and cellular metabolism. In climateric f ruits these events are coordinated by the gaseous hormone ethylene, wh ich: is synthesized autocatalytically in the early stages of ripening. Nonclimacteric fruits do not synthesize or respond to ethylene in thi s manner, yet undergo many of the same physiological and biochemical c hanges associated with the production of a ripe fruit. To gain insight into the molecular determinants associated with nonclimacteric fruit ripening, we examined mRNA. populations in ripening strawberry fruit u sing polymerase chain reaction (PCR) differential display. Five mRNAs with ripening-enhanced expression were identified using this approach. Three of the mRNAs appear to be fruit-specific, with little or no exp ression detected in vegetative tissues. Sequence analysis of cDNA clon es revealed positive identities for three of the five mRNAs based on h omology to known proteins. These results indicate that the differentia l display technique can be a useful tool to study fruit ripening and o ther developmental processes in plants at the RNA level.