Differential combinatorial interactions of cis-acting elements recognized by R2R3-MYB, BZIP, and BHLH factors control light-responsive and tissue-specific activation of phenylpropanoid biosynthesis genes.
Chalcone synthase (CHS), chalcone flavanone isomerase (CFI), flavanone 3-hydroxylase (F3H) and flavonol synthase (FLS) catalyze successive steps in the biosynthetic pathway leading to the production of flavonols. We show that in Arabidopsis thaliana all four corresponding genes are coordinately expressed in response to light, and are spatially coexpressed in siliques, flowers and leaves. Light regulatory units (LRUs) sufficient for light responsiveness were identified in all four promoters. Each unit consists of two necessary elements, namely a MYB-recognition element (MRE) and an ACGT-containing element (ACE). C1 and Sn, a R2R3-MYB and a BHLH factor, respectively, known to control tissue specific anthocyanin biosynthesis in Z. mays, were together able to activate the AtCHS promoter. This activation of the CHS promoter required an intact MRE and a newly identified sequence designated R response element (RREAtCHS) containing the BHLH factor consensus binding site CANNTG. The RRE was dispensable for light responsiveness, and the ACE was not necessary for activation by C1/Sn. These data suggest that a BHLH and a R2R3-MYB factor cooperate in directing tissue-specific production of flavonoids, while an ACE-binding factor, potentially a BZIP, and a R2R3-MYB factor work together in conferring light responsiveness.
Hartmann
Ulrike
U
Department of Plant Breeding and Yield Physiology, Max-Planck-Institute for Plant Breeding Research, Carl-von-Linné-Weg 10, D-50829 Köln, Germany.
Sagasser
Martin
M
Mehrtens
Frank
F
Stracke
Ralf
R
Weisshaar
Bernd
B
D000217:Acyltransferases / Q000235:genetics / Q000378:metabolism; D017360:Arabidopsis / Q000166:cytology / Q000235:genetics / Q000378:metabolism; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism; D001483:Base Sequence; D051792:Basic Helix-Loop-Helix Proteins; D050976:Basic-Leucine Zipper Transcription Factors; D001665:Binding Sites / Q000235:genetics; D001667:Binding, Competitive; D002478:Cells, Cultured; D003513:Cycloheximide / Q000494:pharmacology; D004268:DNA-Binding Proteins / Q000378:metabolism*; D005419:Flavonoids / Q000096:biosynthesis*; D051790:G-Box Binding Factors; D015971:Gene Expression Regulation, Enzymologic / Q000187:drug effects / Q000528:radiation effects; D018506:Gene Expression Regulation, Plant / Q000187:drug effects / Q000528:radiation effects; D019753:Intramolecular Lyases / Q000235:genetics / Q000378:metabolism; D016350:Leucine Zippers / Q000235:genetics; D008027:Light; D006899:Mixed Function Oxygenases / Q000235:genetics / Q000378:metabolism; D009154:Mutation; D010088:Oxidoreductases / Q000235:genetics / Q000378:metabolism; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism; D011401:Promoter Regions, Genetic / Q000235:genetics; D011485:Protein Binding; D011500:Protein Synthesis Inhibitors / Q000494:pharmacology; D020598:Proto-Oncogene Proteins c-myb / Q000378:metabolism; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D020218:Response Elements / Q000235:genetics*; D014157:Transcription Factors / Q000378:metabolism*; D014162:Transfection; D016335:Zinc Fingers / Q000235:genetics
D000217:Acyltransferases; D029681:Arabidopsis Proteins; D051792:Basic Helix-Loop-Helix Proteins; D050976:Basic-Leucine Zipper Transcription Factors; D003513:Cycloheximide; D004268:DNA-Binding Proteins; D005419:Flavonoids; D051790:G-Box Binding Factors; D019753:Intramolecular Lyases; D006899:Mixed Function Oxygenases; D010088:Oxidoreductases; D010940:Plant Proteins; D011500:Protein Synthesis Inhibitors; D020598:Proto-Oncogene Proteins c-myb; D012333:RNA, Messenger; D014157:Transcription Factors; C511988:ATR1 protein, Arabidopsis; C511989:CPC protein, Arabidopsis; C048797:flavanone 3-dioxygenase; C085313:flavonol synthase; C020141:flavanone synthetase; C019865:chalcone isomerase