Abstract
Besides the resistance to insect and pathogen attacks, the jasmonic acid (JA) has an important role to open flowers, i.e. to start the elongation of floral organs in fully developed flower buds, in Arabidopsis and related species. In flower buds, the JA is accumulated in stamens, in which most genes for JA biosynthetic enzymes are highly expressed. We have focused on the expression of DEFECTIVE IN ANTHER DEHISCENCE1 (DAD1) gene, which encodes a lipase responsible for the first step of JA biosynthesis. The DAD1 expression first appeared in stamens two days before flower opening, which was fitted to the initiation timing of JA accumulation. Therefore, the DAD1 expression may function as a switch to turn on the flower opening. In order to know the regulatory mechanism to activate the DAD1 expression, promoter analyses with many truncated promoters were carried out. We found that the cis-regulatory element responsible for the stamen expression is located within a 49-bp region in the DAD1 promoter.
