Identification of a Jasmonic Acid-Responsive Region in the Promoter of a 12-Oxophytodienoic Acid Reductase Gene, OsOPR1, Isolated from Suspension-Cultured Rice Cells.

Abstract

In suspension-cultured rice cells, transcription of the 12-oxophytodienoic acid reductase gene OsOPR1 was shown to be jasmonic acid (JA)-inducible and the increase in OsOPR1 mRNA levels by JA appears not to require de novo synthesis of proteins. A genomic DNA fragment was isolated containing 5^' upstream sequences of OsOPR1, and transient gene expression assays using the firefly luciferase reporter gene were performed to identify a promoter region involved in JA-responsive expression. Analysis of 5^' promoter deletions indicated that sequences between -880 and -860 conferred JA-responsive expression. This 20-bp fragment contains the motif TGACG, which has been previously identified as a binding site for bZIP transactivation factors. Site-directed mutagenesis on the TGACG motif abolished JA-responsive expression, clearly identifying this motif as a JA-responsive element.