title: Selective protein denitrosylation activity of Thioredoxin-h5 modulates plant Immunity.
abstract: In eukaryotes, bursts of reactive oxygen and nitrogen species mediate cellular responses to the environment by modifying cysteines of signaling proteins. Cysteine reactivity toward nitric oxide (NO) leads to formation of S-nitrosothiols (SNOs) that play important roles in pathogenesis and immunity. However, it remains poorly understood how SNOs are employed as specific, reversible signaling cues. Here we show that in plant immunity the oxidoreductase Thioredoxin-h5 (TRXh5) reverses SNO modifications by acting as a selective protein-SNO reductase. While TRXh5 failed to restore immunity in gsnor1 mutants that display excessive accumulation of the NO donor S-nitrosoglutathione, it rescued immunity in nox1 mutants that exhibit elevated levels of free NO. Rescue by TRXh5 was conferred through selective denitrosylation of excessive protein-SNO, which reinstated signaling by the immune hormone salicylic acid. Our data indicate that TRXh5 discriminates between protein-SNO substrates to provide previously unrecognized specificity and reversibility to protein-SNO signaling in plant immunity.
authors.affiliation: Institute of Molecular Plant Sciences, School of Biological Sciences, University of Edinburgh, Edinburgh EH9 3JR, UK.
authors.forename: Sophie
authors.initials: S
authors.lastname: Kneeshaw
authors.affiliation: Institute of Molecular Plant Sciences, School of Biological Sciences, University of Edinburgh, Edinburgh EH9 3JR, UK.
authors.forename: Silvère
authors.initials: S
authors.lastname: Gelineau
authors.affiliation: The Center for Gene Research, Division of Biological Science, Nagoya University, Nagoya, 464-8602, Japan.
authors.forename: Yasuomi
authors.initials: Y
authors.lastname: Tada
authors.affiliation: Institute of Molecular Plant Sciences, School of Biological Sciences, University of Edinburgh, Edinburgh EH9 3JR, UK.
authors.forename: Gary J
authors.initials: GJ
authors.lastname: Loake
authors.affiliation: Institute of Molecular Plant Sciences, School of Biological Sciences, University of Edinburgh, Edinburgh EH9 3JR, UK. Electronic address: steven.spoel@ed.ac.uk.
authors.forename: Steven H
authors.initials: SH
authors.lastname: Spoel
mesh_terms: D017360:Arabidopsis / Q000235:genetics / Q000276:immunology* / Q000378:metabolism; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D057865:Plant Immunity; D011499:Protein Processing, Post-Translational; D026403:S-Nitrosothiols / Q000378:metabolism*; D015398:Signal Transduction; D054480:Thioredoxin h / Q000235:genetics / Q000378:metabolism / Q000502:physiology*
chemical_list: C521261:ATH5 protein, Arabidopsis; D029681:Arabidopsis Proteins; D026403:S-Nitrosothiols; D054480:Thioredoxin h