Transcription factor WRKY23 assists auxin distribution patterns during Arabidopsis root development through local control on flavonol biosynthesis.
Gradients of the plant hormone auxin, which depend on its active intercellular transport, are crucial for the maintenance of root meristematic activity. This directional transport is largely orchestrated by a complex interaction of specific influx and efflux carriers that mediate the auxin flow into and out of cells, respectively. Besides these transport proteins, plant-specific polyphenolic compounds known as flavonols have been shown to act as endogenous regulators of auxin transport. However, only limited information is available on how flavonol synthesis is developmentally regulated. Using reduction-of-function and overexpression approaches in parallel, we demonstrate that the WRKY23 transcription factor is needed for proper root growth and development by stimulating the local biosynthesis of flavonols. The expression of WRKY23 itself is controlled by auxin through the Auxin Response Factor 7 (ARF7) and ARF19 transcriptional response pathway. Our results suggest a model in which WRKY23 is part of a transcriptional feedback loop of auxin on its own transport through local regulation of flavonol biosynthesis.
Department of Plant Systems Biology, VIB, 9052 Ghent, Belgium. wigru@psb.ugent.be
Wim
W
Grunewald
Ive
I
De Smet
Daniel R
DR
Lewis
Christian
C
Löfke
Leentje
L
Jansen
Geert
G
Goeminne
Robin
R
Vanden Bossche
Mansour
M
Karimi
Bert
B
De Rybel
Bartel
B
Vanholme
Thomas
T
Teichmann
Wout
W
Boerjan
Marc C E
MC
Van Montagu
Godelieve
G
Gheysen
Gloria K
GK
Muday
Jirí
J
Friml
Tom
T
Beeckman
D017360:Arabidopsis / Q000235:genetics / Q000254:growth & development / Q000378:metabolism*; D029681:Arabidopsis Proteins / Q000378:metabolism / Q000502:physiology*; D044948:Flavonols / Q000096:biosynthesis*; D018506:Gene Expression Regulation, Plant / Q000502:physiology; D007210:Indoleacetic Acids / Q000378:metabolism; D018517:Plant Roots / Q000254:growth & development*; D060888:Real-Time Polymerase Chain Reaction; D014157:Transcription Factors / Q000378:metabolism / Q000502:physiology*
D029681:Arabidopsis Proteins; D044948:Flavonols; D007210:Indoleacetic Acids; D014157:Transcription Factors; C532783:WRKY23 protein, Arabidopsis