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.
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Footnotes
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Supplemental material is available at http://www.genesdev.org.
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Article and publication are at http://www.genesdev.org/cgi/doi/10.1101/gad.364005.
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↵4 Corresponding author.
↵4 E-MAIL ida.ruberti{at}uniroma1.it; FAX 39-06-4991-2500.
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- Accepted September 29, 2005.
- Received August 25, 2005.
- Cold Spring Harbor Laboratory Press