Abstract
Mechanical damage elicits various defense responses in plants. These responses are preceded by a rapid and transient burst of jasmonic acid (JA) which is supposed to act as a key signal molecule in wound-inducible gene activation. JA synthesis and signaling are interlinked by a positive feedback loop whereby jasmonates stimulates their own synthesis. It was shown that some JA biosynthetic genes such as LOX2 and AOS can be induced in COI1-dependent manner after wounding. JA biosynthesis is regulated by the availability of the substrate, α-linolenic acid, liberated from membrane lipids by phospholipases. The DEFECTIVE IN ANTHER DEHISCENCE1 (DAD1) gene largely contribute to JA production. The aim of our study was to examine whether the expression of DAD1 and its paralogs is also regulated by JA. We conducted experiments using JA-biosynthesis (aos, opr3) and JA-response mutants (coi1-1, coi1-dad3). Although DAD1 was weakly induced by JA, its expression levels after wounding were significantly reduced in both JA-biosynthesis mutants and even stronger in JA-response mutants. These results suggest that DAD1 may be involved in providing the substrate for self-stimulated JA production.
