title: Identification and characterization of an ABA-activated MAP kinase cascade in Arabidopsis thaliana.
abstract: Abscisic acid (ABA) is a major phytohormone involved in important stress-related and developmental plant processes. Recent phosphoproteomic analyses revealed a large set of ABA-triggered phosphoproteins as putative mitogen-activated protein kinase (MAPK) targets, although the evidence for MAPKs involved in ABA signalling is still scarce. Here, we identified and reconstituted in vivo a complete ABA-activated MAPK cascade, composed of the MAP3Ks MAP3K17/18, the MAP2K MKK3 and the four C group MAPKs MPK1/2/7/14. In planta, we show that ABA activation of MPK7 is blocked in mkk3-1 and map3k17mapk3k18 plants. Coherently, both mutants exhibit hypersensitivity to ABA and altered expression of a set of ABA-dependent genes. A genetic analysis further reveals that this MAPK cascade is activated by the PYR/PYL/RCAR-SnRK2-PP2C ABA core signalling module through protein synthesis of the MAP3Ks, unveiling an atypical mechanism for MAPK activation in eukaryotes. Our work provides evidence for a role of an ABA-induced MAPK pathway in plant stress signalling.
authors.affiliation: Institute of Plant Sciences Paris-Saclay, Institut National de Recherche Agronomique/Centre National de la Recherche Scientifique/Université Paris Sud/Université Paris Diderot/Université d'Evry Val d'Essonne, Saclay Plant Sciences, 91405, Orsay, France.
authors.forename: Agyemang
authors.initials: A
authors.lastname: Danquah
authors.forename: Axel
authors.initials: A
authors.lastname: de Zélicourt
authors.forename: Marie
authors.initials: M
authors.lastname: Boudsocq
authors.forename: Jorinde
authors.initials: J
authors.lastname: Neubauer
authors.forename: Nicolas
authors.initials: N
authors.lastname: Frei Dit Frey
authors.forename: Nathalie
authors.initials: N
authors.lastname: Leonhardt
authors.forename: Stephanie
authors.initials: S
authors.lastname: Pateyron
authors.forename: Frederik
authors.initials: F
authors.lastname: Gwinner
authors.forename: Jean-Philippe
authors.initials: JP
authors.lastname: Tamby
authors.forename: Dolores
authors.initials: D
authors.lastname: Ortiz-Masia
authors.forename: Maria J
authors.initials: MJ
authors.lastname: Marcote
authors.forename: Heribert
authors.initials: H
authors.lastname: Hirt
authors.forename: Jean
authors.initials: J
authors.lastname: Colcombet
mesh_terms: D000040:Abscisic Acid / Q000378:metabolism*; D017360:Arabidopsis / Q000201:enzymology* / Q000378:metabolism*; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D020935:MAP Kinase Signaling System / Q000502:physiology
chemical_list: D029681:Arabidopsis Proteins; D000040:Abscisic Acid
keywords: Arabidopsis thaliana; MAP3K18; MAPK module; MKK3; abscisic acid; signalling pathway