CESTA, a positive regulator of brassinosteroid biosynthesis

• DOI: 10.1038/emboj.2011.35
• Publication Date: 2011-02-18T15:14:35Z
• Authors: Brigitte Poppenbe...; Wilfried Rozhon; Mamoona Khan; Sigrid Husar; Gerhard Adam; Christian Luschnig; Shozo Fujioka; Tobias Sieberer
• Keywords: 106022 Mikrobiologie; 0303 health sciences; Arabidopsis Proteins; Arabidopsis; Article; Biosynthetic Pathways; 03 medical and health sciences; Steroids, Heterocyclic; Gene Expression Regulation; Plant Growth Regulators; Brassinosteroids; Protein Interaction Mapping; 106022 Microbiology; Cholestanols; Transcription Factors

Brassinosteroids (BRs) are steroid hormones that are essential for the development of plants. A tight control of BR homeostasis is vital for modulating their impact on growth responses. Although it is recognized that the rapid adaptation of de novo synthesis has a key role in adjusting required BR levels, our knowledge of the mechanisms governing feedback control is limited. In this study, we identify the transcription factor CESTA as a regulator of BR biosynthesis. ces-D was isolated in a screen of Arabidopsis mutants by BR over-accumulation phenotypes. Loss-of-function analysis and the use of a dominant repressor version revealed functional overlap among CESTA and its homologues and confirmed the role of CESTA in the positive control of BR-biosynthetic gene expression. We provide evidence that CESTA interacts with its homologue BEE1 and can directly bind to a G-box motif in the promoter of the BR biosynthesis gene CPD. Moreover, we show that CESTA subnuclear localization is BR regulated and discuss a model, in which CESTA interplays with BEE1 to control BR biosynthesis and other BR responses.