title: Associating wound-related changes in the apoplast proteome of Medicago with early steps in the ROS signal-transduction pathway.
abstract: Early wound-related changes in the leaf apoplast proteome of Medicago truncatula have been characterized by 2-DE and MALDI-TOF/TOF and the differential expression of 28/110 extracellular proteins could be reproducibly observed 6 h after wounding. Wounding induced an initial (0-30 min) burst of O2-, followed by a later (3-6 h) production of O2- and H2O2. The infiltration of 5 microM DPI<or=3 min after wounding inhibited both phases of the oxidative burst and suppressed wound-regulated changes in 9/28 extracellular proteins. DPI infiltrated 15 min after wounding only partially inhibited early O2- production and was ineffective in suppressing wound-related changes in these proteins. This strongly suggests that in wounded Medicago, rapid O2- is required for mobilizing the downstream (3-6 h), differential expression of several extracellular proteins. Further studies with DPI and exogenous sources of ROS supported the regulation of these proteins within early, wound-related ROS-signaling events. The study forms the basis for associating wound-related changes in the apoplast proteome with ROS-dependent and ROS-independent pathways. Proteins mobilized within the ROS-dependent pathway were largely ionically bound to cell walls and included SODs, peroxidases and germin-like proteins, suggesting their involvement within wound-activated, ROS regulatory loops.
authors.affiliation: Instituto de Tecnologia Química e Biológica, Oeiras, Portugal.
authors.forename: Nelson C
authors.initials: NC
authors.lastname: Soares
authors.forename: Rita
authors.initials: R
authors.lastname: Francisco
authors.forename: Jesus Maria
authors.initials: JM
authors.lastname: Vielba
authors.forename: Cândido Pinto
authors.initials: CP
authors.lastname: Ricardo
authors.forename: Phil A
authors.initials: PA
authors.lastname: Jackson
mesh_terms: D015180:Electrophoresis, Gel, Two-Dimensional; D005110:Extracellular Space / Q000378:metabolism; D006861:Hydrogen Peroxide / Q000378:metabolism; D046913:Medicago truncatula / Q000378:metabolism*; D018515:Plant Leaves / Q000378:metabolism; D010940:Plant Proteins / Q000032:analysis* / Q000145:classification; D020543:Proteome / Q000032:analysis* / Q000145:classification; D017382:Reactive Oxygen Species / Q000378:metabolism*; D015398:Signal Transduction; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; D013314:Stress, Mechanical; D013481:Superoxides / Q000378:metabolism; D013997:Time Factors
chemical_list: D010940:Plant Proteins; D020543:Proteome; D017382:Reactive Oxygen Species; D013481:Superoxides; D006861:Hydrogen Peroxide