title: Reprogramming of fatty acid and oxylipin synthesis in rhizobacteria-induced systemic resistance in tomato.
abstract: The rhizobacterium Pseudomonas putida BTP1 stimulates induced systemic resistance (ISR) in tomato. A previous work showed that the resistance is associated in leaves with the induction of the first enzyme of the oxylipin pathway, the lipoxygenase (LOX), leading to a faster accumulation of its product, the free 13-hydroperoxy octadecatrienoic acid (13-HPOT), 2 days after Botrytis cinerea inoculation. In the present study, we further investigated the stimulation of the oxylipin pathway: metabolites and enzymes of the pathway were analyzed to understand the fate of the 13-HPOT in ISR. Actually the stimulation began upstream the LOX: free linolenic acid accumulated faster in P. putida BTP1-treated plants than in control. Downstream, the LOX products 13-fatty acid hydroperoxides esterified to galactolipids and phospholipids were more abundant in bacterized plants than in control before infection. These metabolites could constitute a pool that will be used after pathogen attack to produce free fungitoxic metabolites through the action of phospholipase A2, which is enhanced in bacterized plants upon infection. Enzymatic branches which can use as substrate the fatty acid hydroperoxides were differentially regulated in bacterized plants in comparison to control plants, so as to lead to the accumulation of the most fungitoxic compounds against B. cinerea. Our study, which is the first to demonstrate the accumulation of an esterified defense metabolite during rhizobacteria-mediated induced systemic resistance, showed that the oxylipin pathway is differentially regulated. It suggests that this allows the plant to prepare to a future infection, and to respond faster and in a more effective way to B. cinerea invasion.
authors.affiliation: Laboratory of Plant Molecular Biology and Biotechnology, Department of Life Sciences, Faculty of Sciences, University of Liège, Boulevard du Rectorat, 27, Liege, Belgium.
authors.forename: Martin
authors.initials: M
authors.lastname: Mariutto
authors.forename: Marie-Laure
authors.initials: ML
authors.lastname: Fauconnier
authors.forename: Marc
authors.initials: M
authors.lastname: Ongena
authors.forename: Morgan
authors.initials: M
authors.lastname: Laloux
authors.forename: Jean-Paul
authors.initials: JP
authors.lastname: Wathelet
authors.forename: Patrick
authors.initials: P
authors.lastname: du Jardin
authors.forename: Philippe
authors.initials: P
authors.lastname: Thonart
authors.forename: Jacques
authors.initials: J
authors.lastname: Dommes
mesh_terms: D053898:Biosynthetic Pathways / Q000235:genetics; D020171:Botrytis / Q000502:physiology; D060467:Disease Resistance / Q000235:genetics; D005227:Fatty Acids / Q000378:metabolism*; D005231:Fatty Acids, Unsaturated / Q000378:metabolism; D018506:Gene Expression Regulation, Plant; D054884:Host-Pathogen Interactions; D008042:Linolenic Acids / Q000378:metabolism; D008054:Lipid Peroxides / Q000378:metabolism; D008084:Lipoxygenase / Q000235:genetics / Q000378:metabolism; D018551:Solanum lycopersicum / Q000235:genetics / Q000378:metabolism* / Q000382:microbiology; D054883:Oxylipins / Q000378:metabolism*; D054466:Phospholipases A1 / Q000378:metabolism; D054467:Phospholipases A2 / Q000378:metabolism; D010935:Plant Diseases / Q000235:genetics / Q000382:microbiology; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism*; D016958:Pseudomonas putida / Q000502:physiology; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013997:Time Factors; D017962:alpha-Linolenic Acid / Q000378:metabolism
chemical_list: D005227:Fatty Acids; D005231:Fatty Acids, Unsaturated; D008042:Linolenic Acids; D008054:Lipid Peroxides; D054883:Oxylipins; D010940:Plant Proteins; D017962:alpha-Linolenic Acid; C057375:13-hydroperoxy-9,11,15-octadecatrienoic acid; C117433:13-lipoxygenase; D008084:Lipoxygenase; D054466:Phospholipases A1; D054467:Phospholipases A2