title: RNA interference-based (RNAi) suppression of AtMPK6, an Arabidopsis mitogen-activated protein kinase, results in hypersensitivity to ozone and misregulation of AtMPK3.
abstract: The recent increase in tropospheric ozone (O(3)) concentrations promotes additional oxidative stress through the production of reactive oxygen species (ROS) in plant tissues, resulting in the activation of genes whose products enable the stressed cells to retain their integrity and function. This response is made possible by an integration of highly regulated signaling networks that mediate the perception of, and response to, this oxidative assault. In Arabidopsis thaliana, ROS-induced signaling has been shown to flow through a protein phosphorylation cascade involving the mitogen-activated protein kinases (MAPKs) AtMPK3 (MPK3) and AtMPK6 (MPK6). We found that RNAi-mediated silencing of MPK6 renders the plant more sensitive to ozone, as determined by visible leaf damage. The MPK6-RNAi genotype also displayed a more intense and prolonged activation of MPK3 compared to that of WT plants. An MPK3 loss-of-function genotype is similarly very sensitive to ozone, and displays an abnormally prolonged MPK6 activation profile, suggesting reciprocity in regulation between these two MAPKs.
authors.affiliation: Michael Smith Laboratories, University of British Columbia, 2185 East Mall, Vancouver, British Columbia, Canada, V6T 1Z4.
authors.forename: Godfrey P
authors.initials: GP
authors.lastname: Miles
authors.forename: Marcus A
authors.initials: MA
authors.lastname: Samuel
authors.forename: Yuelin
authors.initials: Y
authors.lastname: Zhang
authors.forename: Brian E
authors.initials: BE
authors.lastname: Ellis
mesh_terms: D017360:Arabidopsis / Q000201:enzymology* / Q000235:genetics; D029681:Arabidopsis Proteins / Q000037:antagonists & inhibitors* / Q000378:metabolism*; D004794:Enzyme Repression; D018506:Gene Expression Regulation, Plant; D020935:MAP Kinase Signaling System; D020929:Mitogen-Activated Protein Kinase Kinases / Q000037:antagonists & inhibitors* / Q000378:metabolism; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism*; D010083:Oxidants, Photochemical / Q000378:metabolism / Q000633:toxicity*; D018384:Oxidative Stress; D010126:Ozone / Q000378:metabolism / Q000633:toxicity*; D030821:Plants, Genetically Modified; D034622:RNA Interference; D017382:Reactive Oxygen Species / Q000378:metabolism
chemical_list: D029681:Arabidopsis Proteins; D010083:Oxidants, Photochemical; D017382:Reactive Oxygen Species; D010126:Ozone; C458516:AtMPK3 protein, Arabidopsis; C436293:MPK6 protein, Arabidopsis; D020928:Mitogen-Activated Protein Kinases; D020929:Mitogen-Activated Protein Kinase Kinases