Encoding of a cytochrome P450-dependent lauric acid monooxygenase by CYP703A1 specifically expressed in the floral buds of petunia hybrida.

The cDNA clone of novel cytochrome P450 CYP703A1 from petunia floral buds was isolated by RT-PCR. The nucleotide sequences of this cDNA clone contained the open reading frame that has been predicted to encode polypeptides consisting of 539 amino acid residues. A significantly high level of the transcript of the cyp703A1 gene was found in the early stage of petunia flower buds, but not in the leaves, stems and roots. The 1041bp 5'-flanking sequences of the cyp703A1 gene contained the conserved motifs of ATHB-1, AGAMOUS, MYB.Ph3, P and SBF-1 binding boxes. CYP703A1 cDNA was expressed in yeast Saccharomyces cerevisiae AH22 cells under the control of an alcohol dehydrogenase I promoter and terminator. The recombinant yeast microsomes containing the CYP703A1 hemoprotein were found to metabolize lauric acid. Based on these results, CYP703A1 was specifically expressed in the early stage of flower development and appeared to participate in the monooxygenation of fatty acids.