Plant immunity strategies against microbial pathogen infection

Plant oxylipins are a class of lipid signals involved in regulating plant development and immunity. Recent studies demonstrate the importance of the 9-LOX and alpha-DOX oxylipin pathways in the defence mechanisms activated by Arabidopsis following infection by hemibiotrophic bacteria in which these oxylipin pathways participate in the three layers of defence -pre-invasion, apoplastic and systemic defence- triggered by plants to prevent Pseudomonas syringae pv tomato DC3000 infection. Our studies also showed high 9-LOX and alpha-DOX levels activity in roots of untreated Arabidopsis plants and the participation of the 9-LOX pathway in the defence mechanisms against the root pathogen Fusarium oxysporum. In these responses, oxylipins were found to act as regulators of oxidative stress, lipid peroxidation, hormone homeostasis and cell wall integrity. The characterization of a series of noxy mutants (non-responding to oxylipins) insensitive to the 9 LOX products, 9 hydroxyoctadecatrienoic