title: Nitrate sensing and uptake in Arabidopsis are enhanced by ABI2, a phosphatase inactivated by the stress hormone abscisic acid.
abstract: Living organisms sense and respond to changes in nutrient availability to cope with diverse environmental conditions. Nitrate (NO3-) is the main source of nitrogen for plants and is a major component in fertilizer. Unraveling the molecular basis of nitrate sensing and regulation of nitrate uptake should enable the development of strategies to increase the efficiency of nitrogen use and maximize nitrate uptake by plants, which would aid in reducing nitrate pollution. NPF6.3 (also known as NRT1.1), which functions as a nitrate sensor and transporter; the kinase CIPK23; and the calcium sensor CBL9 form a complex that is crucial for nitrate sensing in Arabidopsis thaliana. We identified two additional components that regulate nitrate transport, sensing, and signaling: the calcium sensor CBL1 and protein phosphatase 2C family member ABI2, which is inhibited by the stress-response hormone abscisic acid. Bimolecular fluorescence complementation assays and in vitro kinase assays revealed that ABI2 interacted with and dephosphorylated CIPK23 and CBL1. Coexpression studies in Xenopus oocytes and analysis of plants deficient in ABI2 indicated that ABI2 enhanced NPF6.3-dependent nitrate transport, nitrate sensing, and nitrate signaling. These findings suggest that ABI2 may functionally link stress-regulated control of growth and nitrate uptake and utilization, which are energy-expensive processes.
authors.affiliation: Laboratoire de Biochimie et Physiologie Moléculaire des Plantes, UMR CNRS/INRA/SupAgro/UM, Institut de Biologie Intégrative des Plantes "Claude Grignon," Place Viala, 34060 Montpellier Cedex, France.
authors.forename: Sophie
authors.initials: S
authors.lastname: Léran
authors.affiliation: Institut für Biologie und Biotechnologie der Pflanzen, Universität Münster, Schlossplatz 7, 48149 Münster, Germany.
authors.forename: Kai H
authors.initials: KH
authors.lastname: Edel
authors.affiliation: Laboratoire de Biochimie et Physiologie Moléculaire des Plantes, UMR CNRS/INRA/SupAgro/UM, Institut de Biologie Intégrative des Plantes "Claude Grignon," Place Viala, 34060 Montpellier Cedex, France.
authors.forename: Marjorie
authors.initials: M
authors.lastname: Pervent
authors.affiliation: Institut für Biologie und Biotechnologie der Pflanzen, Universität Münster, Schlossplatz 7, 48149 Münster, Germany.
authors.forename: Kenji
authors.initials: K
authors.lastname: Hashimoto
authors.affiliation: Laboratoire de Biochimie et Physiologie Moléculaire des Plantes, UMR CNRS/INRA/SupAgro/UM, Institut de Biologie Intégrative des Plantes "Claude Grignon," Place Viala, 34060 Montpellier Cedex, France.
authors.forename: Claire
authors.initials: C
authors.lastname: Corratgé-Faillie
authors.affiliation: Institut für Biologie und Biotechnologie der Pflanzen, Universität Münster, Schlossplatz 7, 48149 Münster, Germany.
authors.forename: Jan Niklas
authors.initials: JN
authors.lastname: Offenborn
authors.affiliation: Laboratoire de Biochimie et Physiologie Moléculaire des Plantes, UMR CNRS/INRA/SupAgro/UM, Institut de Biologie Intégrative des Plantes "Claude Grignon," Place Viala, 34060 Montpellier Cedex, France.
authors.forename: Pascal
authors.initials: P
authors.lastname: Tillard
authors.affiliation: Laboratoire de Biochimie et Physiologie Moléculaire des Plantes, UMR CNRS/INRA/SupAgro/UM, Institut de Biologie Intégrative des Plantes "Claude Grignon," Place Viala, 34060 Montpellier Cedex, France.
authors.forename: Alain
authors.initials: A
authors.lastname: Gojon
authors.affiliation: Institut für Biologie und Biotechnologie der Pflanzen, Universität Münster, Schlossplatz 7, 48149 Münster, Germany.
authors.forename: Jörg
authors.initials: J
authors.lastname: Kudla
authors.affiliation: Laboratoire de Biochimie et Physiologie Moléculaire des Plantes, UMR CNRS/INRA/SupAgro/UM, Institut de Biologie Intégrative des Plantes "Claude Grignon," Place Viala, 34060 Montpellier Cedex, France. benoit.lacombe@supagro.inra.fr.
authors.forename: Benoît
authors.initials: B
authors.lastname: Lacombe
mesh_terms: D000040:Abscisic Acid / Q000235:genetics / Q000378:metabolism*; D000818:Animals; D027321:Anion Transport Proteins / Q000235:genetics / Q000378:metabolism; D017360:Arabidopsis / Q000235:genetics / Q000378:metabolism*; D001693:Biological Transport, Active / Q000502:physiology; D009566:Nitrates / Q000378:metabolism*; D010749:Phosphoprotein Phosphatases / Q000235:genetics / Q000378:metabolism*; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism; D013312:Stress, Physiological; D014982:Xenopus laevis
chemical_list: D027321:Anion Transport Proteins; C101492:NRT1.1 protein, Arabidopsis; D009566:Nitrates; D010940:Plant Proteins; D000040:Abscisic Acid; C106443:ABI2 protein, Arabidopsis; D010749:Phosphoprotein Phosphatases