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The Arabidopsis bZIP transcription factor HY5 regulates expression of the PFG1 / MYB12 gene in response to light and ultraviolet‐B radiation
Author(s) -
STRACKE RALF,
FAVORY JEANJACQUES,
GRUBER HENRIETTE,
BARTELNIEWOEHNER LUTZ,
BARTELS SEBASTIAN,
BINKERT MELANIE,
FUNK MARKUS,
WEISSHAAR BERND,
ULM ROMAN
Publication year - 2010
Publication title -
plant, cell and environment
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.646
H-Index - 200
eISSN - 1365-3040
pISSN - 0140-7791
DOI - 10.1111/j.1365-3040.2009.02061.x
Subject(s) - arabidopsis , transcription factor , phenylpropanoid , myb , gene , transcription (linguistics) , biology , transcriptional regulation , mutant , gene expression , microbiology and biotechnology , ultraviolet light , genetics , gene family , chemistry , biosynthesis , linguistics , philosophy , photochemistry
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.