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Nat Cell Biol. 2012 Aug;14(8):810-7. doi: 10.1038/ncb2546. Epub 2012 Jul 22.

Brassinosteroid, gibberellin and phytochrome impinge on a common transcription module in Arabidopsis.

Author information

1
Department of Plant Biology, Carnegie Institution for Science, Stanford, California 94305, USA.

Abstract

Brassinosteroid and gibberellin promote many similar developmental responses in plants; however, their relationship remains unclear. Here we show that BR and GA act interdependently through a direct interaction between the BR-activated BZR1 and GA-inactivated DELLA transcription regulators. GA promotion of cell elongation required BR signalling, whereas BR or active BZR1 suppressed the GA-deficient dwarf phenotype. DELLAs directly interacted with BZR1 and inhibited BZR1-DNA binding both in vitro and in vivo. Genome-wide analysis defined a BZR1-dependent GA-regulated transcriptome, which is enriched with light-regulated genes and genes involved in cell wall synthesis and photosynthesis/chloroplast function. GA promotion of hypocotyl elongation requires both BZR1 and the phytochrome-interacting factors (PIFs), as well as their common downstream targets encoding the PRE-family helix-loop-helix factors. The results demonstrate that GA releases DELLA-mediated inhibition of BZR1, and that the DELLA-BZR1-PIF4 interaction defines a core transcription module that mediates coordinated growth regulation by GA, BR and light signals.

PMID:
22820377
PMCID:
PMC3606816
DOI:
10.1038/ncb2546
[Indexed for MEDLINE]
Free PMC Article

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