title: Insights into B-type RR members as signaling partners acting downstream of HPt partners of HK1 in the osmotic stress response in Populus.
abstract: The B-type response regulators (B-type RRs), final elements of a signaling pathway called "histidine/aspartate phosphorelay system" in plants, are devoted to the regulation of response genes through a transcription factor activity. Signal transduction consists in the transfer of a phosphoryl group from a transmembrane histidine kinase (HK) which recognizes a given stimulus to nuclear RRs via cytosolic shuttle phosphotransfer proteins (HPts). In Arabidopsis, the receptors HK are to date the major characterized candidates to be responsible for initiation of osmotic stress responses. However, little information is available concerning the signaling partners acting downstream of HKs. In Populus, three HPts and five B-type RRs were previously identified as interacting partners of HK1, the Arabidopsis AHK1 homolog. Here, we report the isolation of RR18, a member of the B-type RR family, which shares high sequence similarities with ARR18 characterized to act in the osmosensing signaling pathway in Arabidopsis, from poplar cuttings subjected to osmotic stress conditions. By using yeast and in planta interaction assays, RR18 was further identified as acting downstream of HK1 and its three preferential HPt partners. Besides, our results are in favor of a possible involvement of both RR18 and RR13, the main expressed poplar B-type RR, in the osmotic signaling pathway. Nonetheless, different behaviors of these two B-type RRs in this pathway need to be noted, with one RR, RR13, acting in an early phase, mainly in roots of poplar cuttings, and the other one, RR18, acting in a late phase, mainly in leaves to supply an adequate response.
authors.affiliation: Université d'Orléans, UPRES EA 1207, Laboratoire de Biologie des Ligneux et des Grandes Cultures (LBLGC), 45067 Orléans Cedex 2, France; INRA, USC1328, Arbres et Réponses aux Contraintes Hydriques et Environnementales (ARCHE), 45067 Orléans Cedex 2, France; Université de Toulon, EA 3819, Laboratoire Processus de Transferts et d'Echanges dans l'Environnement (PROTEE), 83957 La Garde Cedex, France.
authors.forename: Lucie
authors.initials: L
authors.lastname: Bertheau
authors.affiliation: Université d'Orléans, UPRES EA 1207, Laboratoire de Biologie des Ligneux et des Grandes Cultures (LBLGC), 45067 Orléans Cedex 2, France; INRA, USC1328, Arbres et Réponses aux Contraintes Hydriques et Environnementales (ARCHE), 45067 Orléans Cedex 2, France.
authors.forename: Inès
authors.initials: I
authors.lastname: Djeghdir
authors.affiliation: Université François Rabelais de Tours, EA 2106, Biomolécules et Biotechnologies Végétales (BBV), 37200 Tours, France.
authors.forename: Emilien
authors.initials: E
authors.lastname: Foureau
authors.affiliation: Université d'Orléans, UPRES EA 1207, Laboratoire de Biologie des Ligneux et des Grandes Cultures (LBLGC), 45067 Orléans Cedex 2, France; INRA, USC1328, Arbres et Réponses aux Contraintes Hydriques et Environnementales (ARCHE), 45067 Orléans Cedex 2, France.
authors.forename: Françoise
authors.initials: F
authors.lastname: Chefdor
authors.affiliation: Université François Rabelais de Tours, EA 2106, Biomolécules et Biotechnologies Végétales (BBV), 37200 Tours, France.
authors.forename: Gaëlle
authors.initials: G
authors.lastname: Glevarec
authors.affiliation: Université François Rabelais de Tours, EA 2106, Biomolécules et Biotechnologies Végétales (BBV), 37200 Tours, France.
authors.forename: Audrey
authors.initials: A
authors.lastname: Oudin
authors.affiliation: Université d'Orléans, UPRES EA 1207, Laboratoire de Biologie des Ligneux et des Grandes Cultures (LBLGC), 45067 Orléans Cedex 2, France; INRA, USC1328, Arbres et Réponses aux Contraintes Hydriques et Environnementales (ARCHE), 45067 Orléans Cedex 2, France.
authors.forename: Christiane
authors.initials: C
authors.lastname: Depierreux
authors.affiliation: Université d'Orléans, UPRES EA 1207, Laboratoire de Biologie des Ligneux et des Grandes Cultures (LBLGC), 45067 Orléans Cedex 2, France; INRA, USC1328, Arbres et Réponses aux Contraintes Hydriques et Environnementales (ARCHE), 45067 Orléans Cedex 2, France.
authors.forename: Domenico
authors.initials: D
authors.lastname: Morabito
authors.affiliation: Université d'Orléans, UPRES EA 1207, Laboratoire de Biologie des Ligneux et des Grandes Cultures (LBLGC), 45067 Orléans Cedex 2, France; INRA, USC1328, Arbres et Réponses aux Contraintes Hydriques et Environnementales (ARCHE), 45067 Orléans Cedex 2, France.
authors.forename: Franck
authors.initials: F
authors.lastname: Brignolas
authors.affiliation: Université François Rabelais de Tours, EA 2106, Biomolécules et Biotechnologies Végétales (BBV), 37200 Tours, France.
authors.forename: Vincent
authors.initials: V
authors.lastname: Courdavault
authors.affiliation: Université d'Orléans, UPRES EA 1207, Laboratoire de Biologie des Ligneux et des Grandes Cultures (LBLGC), 45067 Orléans Cedex 2, France; INRA, USC1328, Arbres et Réponses aux Contraintes Hydriques et Environnementales (ARCHE), 45067 Orléans Cedex 2, France.
authors.forename: François
authors.initials: F
authors.lastname: Héricourt
authors.affiliation: Université d'Orléans, UPRES EA 1207, Laboratoire de Biologie des Ligneux et des Grandes Cultures (LBLGC), 45067 Orléans Cedex 2, France; INRA, USC1328, Arbres et Réponses aux Contraintes Hydriques et Environnementales (ARCHE), 45067 Orléans Cedex 2, France.
authors.forename: Daniel
authors.initials: D
authors.lastname: Auguin
authors.affiliation: Université d'Orléans, UPRES EA 1207, Laboratoire de Biologie des Ligneux et des Grandes Cultures (LBLGC), 45067 Orléans Cedex 2, France; INRA, USC1328, Arbres et Réponses aux Contraintes Hydriques et Environnementales (ARCHE), 45067 Orléans Cedex 2, France. Electronic address: sabine.carpin@univ-orleans.fr.
authors.forename: Sabine
authors.initials: S
authors.lastname: Carpin
mesh_terms: D017360:Arabidopsis / Q000235:genetics / Q000378:metabolism; D000071677:Histidine Kinase; D009997:Osmotic Pressure / Q000502:physiology*; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism*; D018517:Plant Roots / Q000235:genetics / Q000378:metabolism; D032107:Populus / Q000235:genetics / Q000378:metabolism*; D011494:Protein Kinases / Q000235:genetics / Q000378:metabolism*; D015398:Signal Transduction / Q000502:physiology*; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*
chemical_list: D010940:Plant Proteins; D014157:Transcription Factors; D011494:Protein Kinases; D000071677:Histidine Kinase
keywords: B-type response regulator; Gene regulation; Histidine containing phosphotransfer protein; Osmotic stress; Populus; Proteins interaction