title: Quantitative proteomics identifies oxidant-induced, AtMPK6-dependent changes in Arabidopsis thaliana protein profiles.
abstract: In Arabidopsis thaliana, oxidant-induced signalling has been shown to utilize the mitogen-activated protein kinase (MAPK), AtMPK6. To identify proteins whose accumulation is altered by ozone in an AtMPK6-dependent manner we employed isotope-coded affinity tagging (ICAT) technology to investigate the impact of AtMPK6-suppression on the protein profiles in Arabidopsis both before (air control) and during continuous ozone (O(3)) fumigation (500 nL L(-1) for 8 h). Among the 150 proteins positively identified and quantified in the O(3)-treated plants, we identified thirteen proteins whose abundance was greater in the AtMPK6-suppressed genotype than in wild-type (WT). These include the antioxidant proteins, monodehydroascorbate reductase, peroxiredoxin Q, and glutathione reductase. A further eighteen proteins were identified whose abundance was lower in the ozone-treated AtMPK6-suppressed line relative to ozone-exposed WT plants. These predominantly comprised proteins involved in carbohydrate-, energy-, and amino acid metabolism, and tetrapyrrole biosynthesis. In control plants, five proteins increased, and nine proteins decreased in abundance in the AtMPK6-suppressed genotype compared to that of the WT, reflecting changes in the protein composition of plants that have AtMPK6 constitutively suppressed. Since a number of these proteins are part of the redox response pathway, and loss of AtMPK6 renders Arabidopsis more susceptible to oxidative stress, we propose that AtMPK6 plays a key role in the plant's overall ability to manage oxidative stress.
authors.affiliation: Michael Smith Laboratories, University of British Columbia, Vancouver, BC, CA, USA. 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: Jeffrey A
authors.initials: JA
authors.lastname: Ranish
authors.forename: Sam M
authors.initials: SM
authors.lastname: Donohoe
authors.forename: Gina M
authors.initials: GM
authors.lastname: Sperrazzo
authors.forename: Brian E
authors.initials: BE
authors.lastname: Ellis
mesh_terms: D017360:Arabidopsis / Q000235:genetics / Q000378:metabolism*; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D018506:Gene Expression Regulation, Plant; D005838:Genotype; D006861:Hydrogen Peroxide / Q000378:metabolism; D007553:Isotope Labeling; D020928:Mitogen-Activated Protein Kinases / Q000235:genetics / Q000378:metabolism*; D018384:Oxidative Stress; D010126:Ozone / Q000378:metabolism*; D040901:Proteomics / Q000379:methods*
chemical_list: D029681:Arabidopsis Proteins; D010126:Ozone; D006861:Hydrogen Peroxide; C436293:MPK6 protein, Arabidopsis; D020928:Mitogen-Activated Protein Kinases