BRX mediates feedback between brassinosteroid levels and auxin signalling in root growth

Details

Serval ID
serval:BIB_60429E73180B
Type
Article: article from journal or magazin.
Collection
Publications
Institution
Title
BRX mediates feedback between brassinosteroid levels and auxin signalling in root growth
Journal
Nature
Author(s)
Mouchel  C. F., Osmont  K. S., Hardtke  C. S.
ISSN
1476-4687 (Electronic)
Publication state
Published
Issued date
09/2006
Volume
443
Number
7110
Pages
458-61
Notes
Journal Article
Research Support, Non-U.S. Gov't --- Old month value: Sep 28
Abstract
Brassinosteroid and auxin decisively influence plant development, and overlapping transcriptional responses to these phytohormones suggest an interaction between the two pathways. However, whether this reflects direct feedback or merely parallel inputs on common targets is unclear. Here we show that in Arabidopsis roots, this interaction is mediated by BREVIS RADIX (BRX), which is required for optimal root growth. We demonstrate that the brx phenotype results from a root-specific deficiency of brassinosteroid and is due to reduced, BRX-dependent expression of a rate-limiting enzyme in brassinosteroid biosynthesis. Unexpectedly, this deficiency affects the root expression level of approximately 15% of all Arabidopsis genes, but the transcriptome profile can be restored to wild type by brassinosteroid treatment. Thus, proper brassinosteroid levels are required for the correct expression of many more genes than previously suspected. Moreover, embryonic or post-embryonic brassinosteroid application fully or partially, respectively, rescues the brx phenotype. Further, auxin-responsive gene expression is globally impaired in brx, demonstrating that brassinosteroid levels are rate-limiting for auxin-responsive transcription. BRX expression is strongly induced by auxin and mildly repressed by brassinolide, which means that BRX acts at the nexus of a feedback loop that maintains threshold brassinosteroid levels to permit optimal auxin action.
Keywords
Arabidopsis/genetics/growth & development/*metabolism Arabidopsis Proteins/genetics/*metabolism Cholestanols/metabolism/pharmacology Feedback, Biochemical Gene Expression Regulation, Plant/drug effects Genetic Complementation Test Indoleacetic Acids/*metabolism/pharmacology Oligonucleotide Array Sequence Analysis Phenotype Plant Growth Regulators/*metabolism/pharmacology Plant Roots/genetics/*growth & development/*metabolism *Signal Transduction/drug effects Steroids, Heterocyclic/metabolism/pharmacology Transcription, Genetic/drug effects
Pubmed
Web of science
Create date
24/01/2008 19:51
Last modification date
20/08/2019 14:17
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