Abstract
In tobacco, nicotine is synthesized from putrescine using PMT (putrescine N-methyl transferase) as the first committed enzyme. Both PMT and A622 (unknown function) are under the genetic control of NIC loci, are expressed in the same tissue- and cell- types, and are induced by jasmonate. To clarify the jasmonate responsive regions in these promoters, we performed promoter analysis by a transient assay in tobacco BY-2 protoplasts using firefly luciferase as a reporter. A jasmonate-responsive region in the PMT promoter was narrowed down to a 24bp minimal sequence, and four copies of the 24bp sequence fused to the CaMV35S minimal promoter was sufficient to mediate jasmonate response. This construct was introduced into Nicotiana tabacum cv. SR1 and the jasmonate responsibility in plant tissues is to be analyzed. We are also trying an activation tagging approach using BY-2 cells to screen regulatory factors of nicotine biosynthesis.
