title: A dynamic balance between gene activation and repression regulates the shade avoidance response in Arabidopsis.
abstract: Plants grown under dense canopies perceive through the phytochrome system a reduction in the ratio of red to far-red light as a warning of competition, and this triggers a series of morphological changes to avoid shade. Several phytochrome signaling intermediates acting as positive regulators of accelerated elongation growth and induction of flowering in shade avoidance have been identified. Here we report that a negative regulatory mechanism ensures that in the presence of far-red-rich light an exaggerated plant response does not occur. Strikingly, this unpredicted negative regulatory mechanism is centrally involved in the attenuation of virtually all plant responses to canopy shade.
authors.affiliation: Institute of Molecular Biology and Pathology, National Research Council, 00185 Rome, Italy.
authors.forename: Giovanna
authors.initials: G
authors.lastname: Sessa
authors.forename: Monica
authors.initials: M
authors.lastname: Carabelli
authors.forename: Massimiliano
authors.initials: M
authors.lastname: Sassi
authors.forename: Andrea
authors.initials: A
authors.lastname: Ciolfi
authors.forename: Marco
authors.initials: M
authors.lastname: Possenti
authors.forename: Francesca
authors.initials: F
authors.lastname: Mittempergher
authors.forename: Jorg
authors.initials: J
authors.lastname: Becker
authors.forename: Giorgio
authors.initials: G
authors.lastname: Morelli
authors.forename: Ida
authors.initials: I
authors.lastname: Ruberti
mesh_terms: D000222:Adaptation, Physiological / Q000235:genetics*; D017360:Arabidopsis / Q000235:genetics / Q000254:growth & development / Q000502:physiology*; D029681:Arabidopsis Proteins / Q000502:physiology; D004268:DNA-Binding Proteins / Q000502:physiology; D017753:Ecosystem; D018506:Gene Expression Regulation, Plant; D018398:Homeodomain Proteins / Q000502:physiology; D008027:Light; D009687:Nuclear Proteins / Q000502:physiology; D010834:Phytochrome / Q000502:physiology; D015398:Signal Transduction; D014157:Transcription Factors / Q000502:physiology; D015533:Transcriptional Activation
chemical_list: D029681:Arabidopsis Proteins; D004268:DNA-Binding Proteins; D018398:Homeodomain Proteins; D009687:Nuclear Proteins; D010834:Phytochrome; D014157:Transcription Factors; C080210:ATHB-2 protein, Arabidopsis; C414438:At1g02340 protein, Arabidopsis; C456844:PIL1 protein, Arabidopsis