A dynamic balance between gene activation and repression regulates the shade avoidance response in Arabidopsis.
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.
Sessa
Giovanna
G
Institute of Molecular Biology and Pathology, National Research Council, 00185 Rome, Italy.
Carabelli
Monica
M
Sassi
Massimiliano
M
Ciolfi
Andrea
A
Possenti
Marco
M
Mittempergher
Francesca
F
Becker
Jorg
J
Morelli
Giorgio
G
Ruberti
Ida
I
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
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