title: A proposed interplay between peroxidase, amine oxidase and lipoxygenase in the wounding-induced oxidative burst in Pisum sativum seedlings.
abstract: Plant surfaces form the barrier between a plant and its environment. Upon damage, the wound healing process begins immediately and is accompanied by a rapid production of extracellular reactive oxygen species (ROS), essential in deterring pathogens, signalling responses and cell wall restructuring. Although many enzymes produce extracellular ROS, it is unclear if ROS-producing enzymes act synergistically. We characterised the oxidative burst of superoxide (O2(·-)) and hydrogen peroxide (H2O2) that follows wounding in pea (Pisum sativum L.) seedlings. Rates of ROS production were manipulated by exogenous application of enzyme substrates and inhibitors. The results indicate significant roles for di-amine oxidases (DAO) and peroxidases (Prx) rather than NADPH oxidase. The burst of O2(·-) was strongly dependent on the presence of H2O2 produced by DAO. Potential substrates released from wounded seedlings included linoleic acid that, upon exogenous application, strongly stimulated catalase-sensitive O2(·-) production. Moreover, a 65kD plasma membrane (PM) guaiacol Prx was found in the secretome of wounded seedlings and showed dependence on linoleic acid for O2(·-) production. Lipoxygenases are suggested to modulate O2(·-) production by consuming polyunsaturated fatty acids in the apoplast. Overall, a O2(·-)-producing mechanism involving H2O2-derived from DAO, linoleic acid and a PM-associated Prx is proposed.
authors.affiliation: Seed Conservation Department, Royal Botanic Gardens, Kew, Wakehurst Place, Ardingly, West Sussex RH17 6TN, UK; Institute of Botany, University of Innsbruck, Sternwartestraße 15, A-6020 Innsbruck, Austria. Electronic address: thomas.roach@uibk.ac.at.
authors.forename: Thomas
authors.initials: T
authors.lastname: Roach
authors.affiliation: Seed Conservation Department, Royal Botanic Gardens, Kew, Wakehurst Place, Ardingly, West Sussex RH17 6TN, UK. Electronic address: l.colville@kew.org.
authors.forename: Louise
authors.initials: L
authors.lastname: Colville
authors.affiliation: School of Life Sciences, University of KwaZulu-Natal, Private Bag X01, Pietermaritzburg, Scottsville 3209, South Africa. Electronic address: rpbeckett@gmail.com.
authors.forename: Richard P
authors.initials: RP
authors.lastname: Beckett
authors.affiliation: Kazan Institute of Biochemistry and Biophysics, Russian Academy of Sciences, P.O. Box 30, Kazan 420111, Russian Federation. Electronic address: fminibayeva@gmail.com.
authors.forename: Farida V
authors.initials: FV
authors.lastname: Minibayeva
authors.affiliation: Commissariat à l'Energie Atomique et aux Energies Alternatives/Cadarache, UMR 7265 CNRS-CEA-Aix Marseille Université, Laboratoire d'Ecophysiologie Moléculaire des Plantes, F-13108 Saint-Paul-lez-Durance, France. Electronic address: michel.havaux@cea.fr.
authors.forename: Michel
authors.initials: M
authors.lastname: Havaux
authors.affiliation: Seed Conservation Department, Royal Botanic Gardens, Kew, Wakehurst Place, Ardingly, West Sussex RH17 6TN, UK; Institute of Botany, University of Innsbruck, Sternwartestraße 15, A-6020 Innsbruck, Austria. Electronic address: ilse.kranner@uibk.ac.at.
authors.forename: Ilse
authors.initials: I
authors.lastname: Kranner
mesh_terms: D006631:Amine Oxidase (Copper-Containing) / Q000378:metabolism*; D002462:Cell Membrane / Q000201:enzymology; D006861:Hydrogen Peroxide / Q000378:metabolism; D019787:Linoleic Acid / Q000378:metabolism; D015227:Lipid Peroxidation; D008084:Lipoxygenase / Q000378:metabolism*; D018532:Pisum sativum / Q000166:cytology* / Q000201:enzymology* / Q000378:metabolism / Q000502:physiology; D010544:Peroxidases / Q000378:metabolism*; D016897:Respiratory Burst; D036226:Seedlings / Q000378:metabolism*; D013481:Superoxides / Q000378:metabolism
chemical_list: D013481:Superoxides; D019787:Linoleic Acid; D006861:Hydrogen Peroxide; D010544:Peroxidases; D008084:Lipoxygenase; D006631:Amine Oxidase (Copper-Containing)
keywords: Amine oxidase; Hydrogen peroxide; Linoleic acid; Oxidative burst; Peroxidase; Pisum sativum; Rboh; Seedling; Superoxide; Wounding