title: Brassinosteroid, gibberellin and phytochrome impinge on a common transcription module in Arabidopsis.
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.
authors: Department of Plant Biology, Carnegie Institution for Science, Stanford, California 94305, USA.
authors: Ming-Yi
authors: MY
authors: Bai
authors: Jian-Xiu
authors: JX
authors: Shang
authors: Eunkyoo
authors: E
authors: Oh
authors: Min
authors: M
authors: Fan
authors: Yang
authors: Y
authors: Bai
authors: Rodolfo
authors: R
authors: Zentella
authors: Tai-Ping
authors: TP
authors: Sun
authors: Zhi-Yong
authors: ZY
authors: Wang
mesh_terms: D017360:Arabidopsis / Q000235:genetics* / Q000254:growth & development / Q000378:metabolism; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D051792:Basic Helix-Loop-Helix Proteins / Q000235:genetics / Q000378:metabolism; D060406:Brassinosteroids / Q000378:metabolism*; D049108:Cell Enlargement; D004268:DNA-Binding Proteins; D018506:Gene Expression Regulation, Plant; D005875:Gibberellins / Q000378:metabolism*; D009687:Nuclear Proteins / Q000235:genetics / Q000378:metabolism*; D010834:Phytochrome / Q000378:metabolism*; D060888:Real-Time Polymerase Chain Reaction; D015398:Signal Transduction / Q000187:drug effects; D059467:Transcriptome
chemical_list: D029681:Arabidopsis Proteins; D051792:Basic Helix-Loop-Helix Proteins; D060406:Brassinosteroids; D004268:DNA-Binding Proteins; D005875:Gibberellins; D009687:Nuclear Proteins; D010834:Phytochrome; C454444:BZR1 protein, Arabidopsis; C459466:PIF4 protein, Arabidopsis