Regulation of flavonoid biosynthesis involves an unexpected complex transcriptional regulation of TT8 expression, in Arabidopsis
Open Access
- 12 February 2013
- journal article
- research article
- Published by Wiley in New Phytologist
- Vol. 198 (1), 59-70
- https://doi.org/10.1111/nph.12142
Abstract
TT8/bHLH042 is a key regulator of anthocyanins and proanthocyanidins (PAs) biosynthesis in Arabidopsis thaliana. TT8 transcriptional activity has been studied extensively, and relies on its ability to form, with several R2R3‐MYB and TTG1 (WD‐Repeat protein), different MYB‐bHLH‐WDR (MBW) protein complexes. By contrast, little is known on how TT8 expression is itself regulated. Transcriptional regulation of TT8 expression was studied using molecular, genetic and biochemical approaches. Functional dissection of the TT8 promoter revealed its modular structure. Two modules were found to specifically drive TT8 promoter activity in PA‐ and anthocyanin‐accumulating cells, by differentially integrating the signals issued from different regulators, in a spatio‐temporal manner. Interestingly, this regulation involves at least six different MBW complexes, and an unpredicted positive feedback regulatory loop between TT8 and TTG2. Moreover, the results suggest that some putative new regulators remain to be discovered. Finally, specific cis‐regulatory elements through which TT8 expression is regulated were identified and characterized. Together, these results provide a molecular model consistent with the specific and highly regulated expression of TT8. They shed new light into the transcriptional regulation of flavonoid biosynthesis and provide new clues and tools for further investigation in Arabidopsis and other plant species.Keywords
Funding Information
- China Scholarship Council
This publication has 59 references indexed in Scilit:
- Transcription factor WRKY23 assists auxin distribution patterns during Arabidopsis root development through local control on flavonol biosynthesisProceedings of the National Academy of Sciences of the United States of America, 2012
- Functional characterization of TRICHOMELESS2, a new single-repeat R3 MYB transcription factor in the regulation of trichome patterning in ArabidopsisBMC Plant Biology, 2011
- Transcriptional Regulation of Arabidopsis LEAFY COTYLEDON2 Involves RLE, a cis-Element That Regulates Trimethylation of Histone H3 at Lysine-27Plant Cell, 2011
- Cell Fate in the Arabidopsis Root Epidermis Is Determined by Competition between WEREWOLF and CAPRICEPlant Physiology, 2011
- Using a structural and logics systems approach to infer bHLH–DNA binding specificity determinantsNucleic Acids Research, 2011
- A Multiparameter Network Reveals Extensive Divergence between C. elegans bHLH Transcription FactorsCell, 2009
- TheMYB23Gene Provides a Positive Feedback Loop for Cell Fate Specification in theArabidopsisRoot EpidermisPlant Cell, 2009
- Functional Specialization of the TRANSPARENT TESTA GLABRA1 Network Allows Differential Hormonal Control of Laminal and Marginal Trichome Initiation in Arabidopsis Rosette LeavesPlant Physiology, 2008
- Comprehensive analysis of single-repeat R3 MYB proteins in epidermal cell patterning and their transcriptional regulation in ArabidopsisBMC Plant Biology, 2008
- Arabidopsis TRANSPARENT TESTA GLABRA2Is Directly Regulated by R2R3 MYB Transcription Factors and Is Involved in Regulation ofGLABRA2Transcription in Epidermal DifferentiationPlant Cell, 2007