Article: article from journal or magazin.
Nonenzymatic oxidation of trienoic fatty acids contributes to reactive oxygen species management in Arabidopsis.
Journal of Biological Chemistry
Publication types: Journal Article
In higher plants such as Arabidopsis thaliana, omega-3 trienoic fatty acids (TFAs), represented mainly by alpha-linolenic acid, serve as precursors of jasmonic acid (JA), a potent lipid signal molecule essential for defense. The JA-independent roles of TFAs were investigated by comparing the TFA- and JA-deficient fatty acid desaturase triple mutant (fad3-2 fad7-2 fad8 (fad3 fad7 fad8)) with the aos (allene oxide synthase) mutant that contains TFAs but is JA-deficient. When challenged with the fungus Botrytis, resistance of the fad3 fad7 fad8 mutant was reduced when compared with the aos mutant, suggesting that TFAs play a role in cell survival independently of being the precursors of JA. An independent genetic approach using the lesion mimic mutant accelerated cell death2 (acd2-2) confirmed the importance of TFAs in containing lesion spread, which was increased in the lines in which the fad3 fad7 fad8 and acd2-2 mutations were combined when compared with the aos acd2-2 lines. Malondialdehyde, found to result from oxidative TFA fragmentation during lesion formation, was measured by gas chromatography-mass spectrometry. Its levels correlated with the survival of the tissue. Furthermore, plants lacking TFAs overproduced salicylic acid (SA), hydrogen peroxide, and transcripts encoding several SA-regulated and SA biosynthetic proteins. The data suggest a physiological role for TFAs as sinks for reactive oxygen species.
Apoptosis Regulatory Proteins/genetics, Apoptosis Regulatory Proteins/metabolism, Arabidopsis/metabolism, Arabidopsis/microbiology, Arabidopsis Proteins/genetics, Arabidopsis Proteins/metabolism, Ascomycota, Cyclopentanes/metabolism, Fatty Acid Desaturases/genetics, Fatty Acid Desaturases/metabolism, Hydrogen Peroxide/metabolism, Intramolecular Oxidoreductases/genetics, Intramolecular Oxidoreductases/metabolism, Malondialdehyde/metabolism, Mutation, Oxidation-Reduction, Oxidoreductases/genetics, Oxidoreductases/metabolism, Oxylipins/metabolism, Plant Diseases/genetics, Plant Diseases/microbiology, Reactive Oxygen Species/metabolism, Salicylic Acid/metabolism, alpha-Linolenic Acid/genetics, alpha-Linolenic Acid/metabolism
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