title: Redox rhythm reinforces the circadian clock to gate immune response.
abstract: Recent studies have shown that in addition to the transcriptional circadian clock, many organisms, including Arabidopsis, have a circadian redox rhythm driven by the organism's metabolic activities. It has been hypothesized that the redox rhythm is linked to the circadian clock, but the mechanism and the biological significance of this link have only begun to be investigated. Here we report that the master immune regulator NPR1 (non-expressor of pathogenesis-related gene 1) of Arabidopsis is a sensor of the plant's redox state and regulates transcription of core circadian clock genes even in the absence of pathogen challenge. Surprisingly, acute perturbation in the redox status triggered by the immune signal salicylic acid does not compromise the circadian clock but rather leads to its reinforcement. Mathematical modelling and subsequent experiments show that NPR1 reinforces the circadian clock without changing the period by regulating both the morning and the evening clock genes. This balanced network architecture helps plants gate their immune responses towards the morning and minimize costs on growth at night. Our study demonstrates how a sensitive redox rhythm interacts with a robust circadian clock to ensure proper responsiveness to environmental stimuli without compromising fitness of the organism.
authors.affiliation: 1] Howard Hughes Medical Institute-Gordon and Betty Moore Foundation, Duke University, Durham, North Carolina 27708, USA [2] Department of Biology, PO Box 90338, Duke University, Durham, North Carolina 27708, USA.
authors.forename: Mian
authors.initials: M
authors.lastname: Zhou
authors.affiliation: 1] Howard Hughes Medical Institute-Gordon and Betty Moore Foundation, Duke University, Durham, North Carolina 27708, USA [2] Department of Biology, PO Box 90338, Duke University, Durham, North Carolina 27708, USA.
authors.forename: Wei
authors.initials: W
authors.lastname: Wang
authors.affiliation: Department of Physics, Duke University, Durham, North Carolina 27708, USA.
authors.forename: Sargis
authors.initials: S
authors.lastname: Karapetyan
authors.affiliation: 1] Howard Hughes Medical Institute-Gordon and Betty Moore Foundation, Duke University, Durham, North Carolina 27708, USA [2] Department of Biology, PO Box 90338, Duke University, Durham, North Carolina 27708, USA.
authors.forename: Musoki
authors.initials: M
authors.lastname: Mwimba
authors.affiliation: 1] Howard Hughes Medical Institute-Gordon and Betty Moore Foundation, Duke University, Durham, North Carolina 27708, USA [2] Department of Biology, PO Box 90338, Duke University, Durham, North Carolina 27708, USA.
authors.forename: Jorge
authors.initials: J
authors.lastname: Marqués
authors.affiliation: 1] Department of Biology, PO Box 90338, Duke University, Durham, North Carolina 27708, USA [2] Department of Physics, Duke University, Durham, North Carolina 27708, USA.
authors.forename: Nicolas E
authors.initials: NE
authors.lastname: Buchler
authors.affiliation: 1] Howard Hughes Medical Institute-Gordon and Betty Moore Foundation, Duke University, Durham, North Carolina 27708, USA [2] Department of Biology, PO Box 90338, Duke University, Durham, North Carolina 27708, USA.
authors.forename: Xinnian
authors.initials: X
authors.lastname: Dong
mesh_terms: D017360:Arabidopsis / Q000254:growth & development / Q000276:immunology* / Q000378:metabolism* / Q000382:microbiology; D029681:Arabidopsis Proteins / Q000096:biosynthesis / Q000235:genetics / Q000378:metabolism; D002467:Cell Nucleus / Q000378:metabolism; D057906:Circadian Clocks / Q000187:drug effects / Q000235:genetics / Q000502:physiology*; D002940:Circadian Rhythm / Q000235:genetics / Q000276:immunology / Q000502:physiology; D003624:Darkness; D018506:Gene Expression Regulation, Plant / Q000187:drug effects / Q000235:genetics; D017343:Genes, Plant / Q000235:genetics; D010084:Oxidation-Reduction / Q000187:drug effects; D010935:Plant Diseases / Q000382:microbiology; D057865:Plant Immunity / Q000235:genetics / Q000276:immunology*; D044224:Pseudomonas syringae / Q000502:physiology; D020156:Salicylic Acid / Q000276:immunology / Q000378:metabolism / Q000494:pharmacology; D014157:Transcription Factors / Q000096:biosynthesis / Q000235:genetics; D014158:Transcription, Genetic / Q000235:genetics
chemical_list: D029681:Arabidopsis Proteins; C105496:NPR1 protein, Arabidopsis; C411822:TOC1 protein, Arabidopsis; D014157:Transcription Factors; D020156:Salicylic Acid