Cryptochrome 1 and phytochrome B control shade-avoidance responses in Arabidopsis via partially independent hormonal cascades

Keller, M. M., Jaillais, Y., Pedmale, U. V., Moreno, J. E., Chory, J., Ballare, C. L. (July 2011) Cryptochrome 1 and phytochrome B control shade-avoidance responses in Arabidopsis via partially independent hormonal cascades. Plant J, 67 (2). pp. 195-207. ISSN 0960-7412

URL: http://www.ncbi.nlm.nih.gov/pubmed/21457375
DOI: 10.1111/j.1365-313X.2011.04598.x

Abstract

Plants respond to a reduction in the red/far-red ratio (R:FR) of light, caused by the proximity of other plants, by initiating morphological changes that improve light capture. In Arabidopsis, this response (shade avoidance syndrome, SAS) is controlled by phytochromes (particularly phyB), and is dependent on the TAA1 pathway of auxin biosynthesis. However, when grown in real canopies, we found that phyB mutants and mutants deficient in TAAI (sav3) still display robust SAS responses to increased planting density and leaf shading. The SAS morphology (leaf hyponasty and reduced lamina/petiole ratio) could be phenocopied by exposing plants to blue light attenuation. These responses to blue light attenuation required the UV-A/blue light photoreceptor cry1. Moreover, they were mediated through mechanisms that showed only limited overlap with the pathways recruited by phyB inactivation. In particular, pathways for polar auxin transport, auxin biosynthesis and gibberellin signaling that are involved in SAS responses to low R:FR were not required for the SAS responses to blue light depletion. By contrast, the brassinosteroid response appeared to be required for the full expression of the SAS phenotype under low blue light. The phyB and cry1 inactivation pathways appeared to converge in their requirement for the basic/helix-loop-helix (bHLH) transcription factors PHYTOCHROME INTERACTING FACTORs 4 and 5 (PIF4 and PIF5) to elicit the SAS phenotype. Our results suggest that blue light is an important control of SAS responses, and that PIF4 and PIF5 are critical hubs for a diverse array of signaling routes that control plant architecture in canopies.

Item Type: Paper
Uncontrolled Keywords: Arabidopsis/genetics/*physiology/radiation effects Arabidopsis Proteins/genetics/*metabolism Basic Helix-Loop-Helix Transcription Factors/metabolism Brassinosteroids/metabolism Cryptochromes/genetics/*metabolism Gene Expression Regulation, Plant Indoleacetic Acids/metabolism *Light Mutation Phytochrome B/genetics/*metabolism Plant Leaves/growth & development Signal Transduction
Subjects: organism description > plant > Arabidopsis
bioinformatics > genomics and proteomics > genetics & nucleic acid processing > protein structure, function, modification > protein types > plant proteins > cryptochromes
bioinformatics > genomics and proteomics > genetics & nucleic acid processing > DNA, RNA structure, function, modification > genes, structure and function > gene expression
organism description > plant
bioinformatics > genomics and proteomics > genetics & nucleic acid processing > protein structure, function, modification > protein types > transcription factor
CSHL Authors:
Communities: CSHL labs > Pedmale lab
Depositing User: Matt Covey
Date: July 2011
Date Deposited: 13 Jun 2016 16:59
Last Modified: 13 Jun 2016 16:59
PMCID: PMC3135679
Related URLs:
URI: http://repository.cshl.edu/id/eprint/32858

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