Redox Proteome Perturbation in Arabidopsis upon Pseudomonas syringae Infection

Oxidative burst is one of the earliest plant cellular responses triggered by pathogen infection. Reactive oxygen species can cause oxidative modifications of redox-sensitive proteins to mediate the defense responses. Identification and characterization of proteins that undergo oxidative modifications in these processes is an important step toward understanding molecular mechanisms of plant defense responses. In this study, an in vivo 15N metabolic labeling method combined with a cysteine-containing peptide enrichment technique was applied to identify and quantify proteins and their redox states in Arabidopsis in response to infection by Pseudomonas syringae pv tomato DC3000 (Pst). Changes of peptide redox states were compared and corrected with the changes of protein levels. A total of forty peptides representing thirty-six non-redundant proteins showed significantly redox state changes in response to the infection by the virulent Pst strain and the avirulent Pst strain (Pst avrRpm1), of which 23 had previously not been recognized to undergo oxidative PTMs. The differentially expressed redox-sensitive proteins are involved in cell wall organization, primary metabolism, photosynthesis and stress responses. Interestingly, proteins located at extracellular were more susceptible to be regulated on the redox PTMs level. These findings provide a foundation for further investigation into the redox signaling during plant defense responses.