CLONING AND CHARACTERIZATION OF THE GENE FOR PHYTOENE DESATURASE (PDS) FROM TOMATO (LYCOPERSICON-ESCULENTUM)

The gene Pds encodes phytoene desaturase, a key enzyme in carotenoid b iosynthesis that converts phytoene to zeta-carotene. We have cloned an d analyzed the genomic DNA sequence of Pds from tomato. In tomato Pds is comprised of 15 exons that, together with the introns occupy over 8 kb. A putative promoter sequence has been identified by comparison wi th the cDNA sequence of Pds. A consensus nucleotide sequence around in tron splicing sites in tomato genes was determined by compiling data o n 137 introns in 34 genes. This consensus sequence generally agrees wi th the consensus sequence of other higher plants with only minor diffe rences that are unique to tomato.