Canopy shade causes a rapid and transient arrest in leaf development through auxin-induced cytokinin oxidase activity
- Monica Carabelli1,3,
- Marco Possenti2,3,
- Giovanna Sessa1,
- Andrea Ciolfi1,2,
- Massimiliano Sassi1,
- Giorgio Morelli2, and
- Ida Ruberti1,4
- 1 Institute of Molecular Biology and Pathology, National Research Council, 00185 Rome, Italy;
- 2 National Research Institute for Food and Nutrition, 00178 Rome, Italy
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↵3 These authors contributed equally to this work.
Abstract
A plant grown under canopies perceives the reduction in the ratio of red (R) to far-red (FR) light as a warning of competition, and enhances elongation growth in an attempt to overgrow its neighbors. Here, we report that the same low R/FR signal that induces hypocotyl elongation also triggers a rapid arrest of leaf primordium growth, ensuring that plant resources are redirected into extension growth. The growth arrest induced by low R/FR depends on auxin-induced cytokinin breakdown in incipient vein cells of developing primordia, thus demonstrating the existence of a previously unrecognized regulatory circuit underlying plant response to canopy shade.
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Footnotes
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↵4 Corresponding author.
↵4 E-MAIL ida.ruberti{at}uniroma1.it; FAX 39-06-4991-2500.
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Supplemental material is available at http://www.genesdev.org.
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Article is online at http://www.genesdev.org/cgi/doi/10.1101/gad.432607
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- Received March 13, 2007.
- Accepted June 22, 2007.
- Copyright © 2007, Cold Spring Harbor Laboratory Press