These authors contributed equally to this work.
The Arabidopsis bZIP transcription factor HY5 regulates expression of the PFG1/MYB12 gene in response to light and ultraviolet-B radiation
Article first published online: 4 NOV 2009
© 2009 Blackwell Publishing Ltd
Plant, Cell & Environment
Volume 33, Issue 1, pages 88–103, January 2010
How to Cite
STRACKE, R., FAVORY, J.-J., GRUBER, H., BARTELNIEWOEHNER, L., BARTELS, S., BINKERT, M., FUNK, M., WEISSHAAR, B. and ULM, R. (2010), The Arabidopsis bZIP transcription factor HY5 regulates expression of the PFG1/MYB12 gene in response to light and ultraviolet-B radiation. Plant, Cell & Environment, 33: 88–103. doi: 10.1111/j.1365-3040.2009.02061.x
- Issue published online: 10 DEC 2009
- Article first published online: 4 NOV 2009
- Received 11 August 2009; received in revised form 12 October 2009; accepted for publication 13 October 2009
- abiotic stress;
- gene expression;
- UV-B tolerance
Plants fend off potentially damaging ultraviolet (UV)-B radiation by synthesizing and accumulating UV-B-absorbing flavonols that function as sunscreens. Regulation of this biosynthetic pathway is largely transcriptional and controlled by a network of transcription factors, among which the PRODUCTION OF FLAVONOL GLYCOSIDES (PFG) family of R2R3-MYB transcription factors was recently identified with a pivotal function. Here, we describe the response of Arabidopsis seedlings to narrow-band UV-B radiation at the level of phenylpropanoid pathway genes using whole-genome transcriptional profiling and identify the corresponding flavonol glycosides accumulating under UV-B. We further show that the bZIP transcriptional regulator ELONGATED HYPOCOTYL5 (HY5) is required for the transcriptional activation of the PFG1/MYB12 and PFG3/MYB111 genes under UV-B and visible light. A synthetic protein composed of HY5 with the VP16 activation domain is sufficient to activate PFG1/MYB12 expression in planta. However, even though myb11 myb12 myb111 triple mutants have strongly reduced CHS levels in darkness as well as in constant light, neither light- nor UV-B-inducibility seems impaired. Notwithstanding this, absence of the three PFG family transcription factors results in reduced UV-B tolerance, whereas PFG1/MYB12 overexpression leads to an increased tolerance. Thus, our data suggest that HY5-dependent regulation of PFG gene expression contributes to the establishment of UV-B tolerance.