title: Suppression of MKK5 reduces ozone-induced signal transmission to both MPK3 and MPK6 and confers increased ozone sensitivity in Arabidopsis thaliana.
abstract: In Arabidopsis thaliana, ozone-induced signaling has been shown to involve the mitogen-activated protein kinases (MAPKs) MPK3 and MPK6. To identify a possible ozone-induced mitogen-activated protein kinase kinase (MAPKK) involved in the activation of these specific MAPKs, we employed RNA interference-(RNAi)-based suppression of MKK5, a known cognate MAPKK to both MPK3 and MPK6. When exposed to ozone, activation of both MPK3 and MPK6 was markedly reduced in the MKK5-suppressed plants compared to WT. Additionally, the MKK5-suppressed plants were found to be highly sensitive to ozone as determined by visible leaf damage concomitant with elevated levels of leaf-localised H(2)O(2). Taken together, our data suggest MKK5 functions both in ozone-induced activation of MPK3 and MPK6 and in integrating ROS homeostasis during ozone stress.
authors.affiliation: Michael Smith Laboratories, University of British Columbia, Vancouver, BC, CA. godfrey.miles@ars.usda.gov
authors.forename: Godfrey P
authors.initials: GP
authors.lastname: Miles
authors.forename: Marcus A
authors.initials: MA
authors.lastname: Samuel
authors.forename: Brian E
authors.initials: BE
authors.lastname: Ellis
mesh_terms: D017360:Arabidopsis / Q000737:chemistry / Q000187:drug effects / Q000201:enzymology* / Q000235:genetics / Q000378:metabolism; D029681:Arabidopsis Proteins / Q000378:metabolism*; D004789:Enzyme Activation / Q000187:drug effects; D005838:Genotype; D006861:Hydrogen Peroxide / Q000378:metabolism; D020929:Mitogen-Activated Protein Kinase Kinases / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism*; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism*; D010126:Ozone / Q000494:pharmacology*; D018515:Plant Leaves / Q000187:drug effects / Q000201:enzymology; D030821:Plants, Genetically Modified; D034622:RNA Interference / Q000187:drug effects; D015398:Signal Transduction / Q000187:drug effects*; D013489:Suppression, Genetic
chemical_list: D029681:Arabidopsis Proteins; D010126:Ozone; D006861:Hydrogen Peroxide; C458516:AtMPK3 protein, Arabidopsis; C436293:MPK6 protein, Arabidopsis; D020928:Mitogen-Activated Protein Kinases; C519872:MKK5 protein, Arabidopsis; D020929:Mitogen-Activated Protein Kinase Kinases