title: Redox regulation of the NPR1-TGA1 system of Arabidopsis thaliana by nitric oxide.
abstract: The role of reactive oxygen and nitrogen species in local and systemic defense reactions is well documented. NPR1 and TGA1 are key redox-controlled regulators of systemic acquired resistance in plants. NPR1 monomers interact with the reduced form of TGA1, which targets the activation sequence-1 (as-1) element of the promoter region of defense proteins. Here, we report the effect of the physiological nitric oxide donor S-nitrosoglutathione on the NPR1/TGA1 regulation system in Arabidopsis thaliana. Using the biotin switch method, we demonstrate that both NPR1 and TGA1 are S-nitrosylated after treatment with S-nitrosoglutathione. Mass spectrometry analyses revealed that the Cys residues 260 and 266 of TGA1 are S-nitrosylated and S-glutathionylated even at GSNO concentrations in the low micromolar range. Furthermore, we showed that S-nitrosoglutathione protects TGA1 from oxygen-mediated modifications and enhances the DNA binding activity of TGA1 to the as-1 element in the presence of NPR1. In addition, we observed that the translocation of NPR1 into the nucleus is promoted by nitric oxide. Taken together, our results suggest that nitric oxide is a redox regulator of the NPR1/TGA1 system and that they underline the importance of nitric oxide in the plant defense response.
authors: Institute of Biochemical Plant Pathology, Helmholtz Zentrum München, German Research Center for Environmental Health, D-85764 Neuherberg, Germany.
authors: Christian
authors: C
authors: Lindermayr
authors: Simone
authors: S
authors: Sell
authors: Bernd
authors: B
authors: Müller
authors: Dario
authors: D
authors: Leister
authors: Jörg
authors: J
authors: Durner
mesh_terms: D017360:Arabidopsis / Q000235:genetics* / Q000378:metabolism; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D018506:Gene Expression Regulation, Plant; D016297:Mutagenesis, Site-Directed; D009569:Nitric Oxide / Q000378:metabolism*; D010084:Oxidation-Reduction; D018749:RNA, Plant / Q000235:genetics; D026422:S-Nitrosoglutathione / Q000494:pharmacology
chemical_list: D029681:Arabidopsis Proteins; D004268:DNA-Binding Proteins; C105496:NPR1 protein, Arabidopsis; D018749:RNA, Plant; D009569:Nitric Oxide; D026422:S-Nitrosoglutathione