THE CLONING AND CHARACTERIZATION OF A CDNA-ENCODING A CYTOCHROME-P450 FROM THE FLOWERS OF PETUNIA-HYBRIDA

We have cloned and sequenced a cDNA encoding a P450 protein from petunia flowers. This cDNA is truncated, as it lacks the coding sequence for approximately 80 amino acids in the carboxy-terminal region, as determined by comparing our DNA sequence with that of other P450 genes listed in a genetic sequence database. This protein shows 82% homology with eggplant P450, thus indicating that these two genes form a new P450 gene family, CYP75. The expression of this gene in mutant petunia lines defective in flavonoid synthesis was investigated. Transcripts were detected only in delphinidin producing lines. These results suggest that this gene encodes a flavonoid 3',5'-hydroxylase which produces delphinidin.