Abstract
The plant membrane lipids are characterized by a high content of trienoic fatty acids (TAs). The TA level is regulated in response to abiotic environmental stresses such as wounding. The production of TAs is catalyzed by ω-3 fatty acid desaturase. In Arabidopsis, FAD7 gene encodes one of the plastidial isozyme of the desaturase. TAs serve as the precursor of jasmonic acid, the key regulator of the adaptive responses against wounding. Consistent with this physiological importance of TAs, the level of FAD7 transcripts increases rapidly in response to local wounding treatment. To dissect genetically the wound-signaling pathway controlling the FAD7 expression, transgenic line of Arabidopsis harboring the FAD7 promoter fused to firefly luciferase reporter gene was constructed, which displays bioluminescence in response to local wounding treatment. By screening the progeny of ethyl methanesulfonate-mutagenized seeds of this transgenic line, we isolated some regulatory mutants with defects in the wound-inducible FAD7 expression.
