Identification of differentially expressed genes during early development of tomato fruit. Characterisation of a novel cDNA coding for a RAD23 protein

Before the onset of ripening, tomato fruit development comprises three dist inct phases: fruit set, a cell division phase and a cell expansion phase. I n this study, we used the method of mRNA differential display in order to i solate tomato genes specifically expressed during these early phases of fru it development. Among 40 differential bands, nine cDNAs were selected for f urther investigations based on their identification after nucleotide sequen cing. We isolated the full-length cDNA corresponding to one of these fragme nts, coding for RAD23, a protein involved in the excision repair system, th us providing new sequence information on a poorly characterised protein in plants. All the isolated cDNAs were mapped on the tomato genome and their e xpression studied by northern blot and semi-quantitative RT-PCR during earl y fruit development and in vegetative organs of tomato plants.