A prolonged cold treatment-induced cytochrome P450 gene from Arabidopsis thaliana

The characterization of a full length cytochrome P450 (cyt P450) cDNA clone from Arabidopsis thaliana (CYP83A1) which showed a 2-4-fold transcriptional induction in the shoot apex following a prolonged low temperature treatment is reported, CYP83A1 appears to be encoded by a single copy gene. The gene contains one intron in a position identical to that found in other class A P450 genes. Putative cis-acting elements implicated in the regulation of phenylpropanoid/flavonoid biosynthetic genes (SBF-1, MYB Ph3, and P-MYB) were identified in the promoter region. The coding region was functional in yeast in binding carbon monoxide and tetcyclacis, suggesting that CYP83A1 was produced in its native state enabling it to interact properly with these two cyt P450 inhibitors. However, no activity could be detected when assayed in P450-dependent reactions of gibberellin or phenylpropanoid biosynthesis. Transgenic Arabidopsis plants expressing sense and antisense transcripts did not show any abnormalities or altered flowering time with or without vernalization.