Abstract
Trienoic fatty acids (TAs) are the most abundant fatty acid species constituting the plant membrane lipids. They serve as the precursor of jasmonic acid (JA), the key regulator of defensive responses against wounding. Arabidopsis FAD7 encodes a plastidial isozyme of ω-3 desaturase, which catalyzes the production of TAs. FAD7 expression is induced locally in response to wounding, that depends on JA signaling in roots, but not in leaves. To identify signaling elements required for the induction of FAD7 expression, a transgenic Arabidopsis line harboring a chimeric gene consisting of the FAD7 promoter fused to the firefly luciferase coding sequence (FAD7-LUC) was constructed. Effects of several mutations affecting the biosynthesis and signaling of JA, salicylic acid, and ethylene were examined on the wound-inducible bioluminescence resulting from the FAD7-LUC expression. We also screened for novel mutants with defects in the bioluminescence from the progeny of EMS-mutagenized population of the transgenic line.
