title: Environmental nitrate signals through abscisic acid in the root tip.
abstract: Roots respond to changes in environmental nitrate with a localized stimulation of ABA levels in the root tip. This rise in ABA levels is due to the action of ER-localized β-GLUCOSIDASE 1, which releases bioactive ABA from the inactive ABA-glucose ester. The slow rise in root tip ABA levels stimulates expression of nitrate metabolic enzymes and simultaneously activates a negative feedback loop involving the protein phosphatase, ABI2, which reduces nitrate influx via the AtNPF6.3 transceptor. The rise in root-tip localized ABA also negatively regulates expression of the SCARECROW transcription factor, thus providing a sensitive mechanism for modulating root growth in response to environmental changes.
authors.affiliation: a Department of Plant Biology , University of Vermont , Burlington , VT , USA.
authors.forename: Jeanne M
authors.initials: JM
authors.lastname: Harris
authors.affiliation: b Department of Agricultural and Environmental Sciences , Tennessee State University , Nashville , TN , USA.
authors.forename: Christine A
authors.initials: CA
authors.lastname: Ondzighi-Assoume
mesh_terms: D000040:Abscisic Acid / Q000378:metabolism; D017360:Arabidopsis / Q000235:genetics / Q000378:metabolism*; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D018506:Gene Expression Regulation, Plant; D009566:Nitrates / Q000378:metabolism*; D010937:Plant Growth Regulators / Q000378:metabolism; D018517:Plant Roots / Q000235:genetics / Q000378:metabolism; D030821:Plants, Genetically Modified / Q000235:genetics / Q000378:metabolism*; D015398:Signal Transduction / Q000235:genetics / Q000502:physiology; D001617:beta-Glucosidase / Q000378:metabolism
chemical_list: D029681:Arabidopsis Proteins; D009566:Nitrates; D010937:Plant Growth Regulators; C100978:SCR protein, Arabidopsis; D000040:Abscisic Acid; D001617:beta-Glucosidase
keywords: ABA; ABA-GE; ABI2; Abscisic Acid; Arabidopsis thaliana; AtNPF6.3; SCARECROW; deconjugation; endodermis; environmental signals; nitrate; root; root growth; root tip; β-GLUCOSIDASE 1