ABSTRACT
Products of the oxidation of lipids and the resulting metabolites are collectively called oxylipins. Cross-talk between lipid- and salicylic acid-dependent signal transduction pathways in pathogen defence responses has been observed in a number of studies, and generally involves antagonistic interactions. Oxylipins act as signal molecules, as antimicrobial compounds and they are implicated in lipid peroxidation processes. Lipoxygenasess (LOXs) catalyse at least three different types of reactions: dioxygenation of lipid substrates leading to hydroperoxy lipids, secondary conversion of hydroperoxy lipids leading to keto lipids and formation of epoxy leukotrienes. The antimicrobial activity of 9-LOX-derived oxylipins might contribute to containment of pathogen growth, thus, enhancing the plants’ defence capacity. The LOX pathway starts with the LOX reaction leading to formation of hydroperoxy polyunsaturated fatty acids, which then serve as substrates for at least eight different enzyme families in plants forming the different branches of the LOX pathway.
