Flavonol-induced changes in PIN2 polarity and auxin transport in the Arabidopsis thaliana rol1-2 mutant require phosphatase activity.
The phytohormone auxin is a major determinant and regulatory component important for plant development. Auxin transport between cells is mediated by a complex system of transporters such as AUX1/LAX, PIN, and ABCB proteins, and their localization and activity is thought to be influenced by phosphatases and kinases. Flavonols have been shown to alter auxin transport activity and changes in flavonol accumulation in the Arabidopsis thaliana rol1-2 mutant cause defects in auxin transport and seedling development. A new mutation in ROOTS CURL IN NPA 1 (RCN1), encoding a regulatory subunit of the phosphatase PP2A, was found to suppress the growth defects of rol1-2 without changing the flavonol content. rol1-2 rcn1-3 double mutants show wild type-like auxin transport activity while levels of free auxin are not affected by rcn1-3. In the rol1-2 mutant, PIN2 shows a flavonol-induced basal-to-apical shift in polar localization which is reversed in the rol1-2 rcn1-3 to basal localization. In vivo analysis of PINOID action, a kinase known to influence PIN protein localization in a PP2A-antagonistic manner, revealed a negative impact of flavonols on PINOID activity. Together, these data suggest that flavonols affect auxin transport by modifying the antagonistic kinase/phosphatase equilibrium.
Institute of Plant and Microbial Biology, University of Zurich, Zurich Switzerland.
Benjamin M
BM
Kuhn
Mendel Centre for Plant Genomics and Proteomics, Central European Institute of Technology (CEITEC), Masaryk University, Kamenice 5, CZ-625 00 Brno, Czech Republic.
Tomasz
T
Nodzyński
Institute of Plant and Microbial Biology, University of Zurich, Zurich Switzerland.
Sanae
S
Errafi
Institute of Chemistry, University of Zurich, Zurich, Switzerland.
Rahel
R
Bucher
Institute of Plant and Microbial Biology, University of Zurich, Zurich Switzerland.
Shibu
S
Gupta
Department of Biology - geislerLab, University of Fribourg, Fribourg, Switzerland.
Bibek
B
Aryal
Institute of Experimental Botany, Academy of Sciences of the Czech Republic, Prague, Czech Republic.
Petre
P
Dobrev
Institute of Chemistry, University of Zurich, Zurich, Switzerland.
Laurent
L
Bigler
Department of Biology - geislerLab, University of Fribourg, Fribourg, Switzerland.
Markus
M
Geisler
Institute of Experimental Botany, Academy of Sciences of the Czech Republic, Prague, Czech Republic.
Eva
E
Zažímalová
Institute of Science and Technology Austria (IST Austria), Am Campus 1, 3400 Klosterneuburg, Austria.
Jiří
J
Friml
Institute of Plant and Microbial Biology, University of Zurich, Zurich Switzerland.
Christoph
C
Ringli
D017360:Arabidopsis / Q000187:drug effects / Q000235:genetics / Q000378:metabolism*; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D005419:Flavonoids / Q000494:pharmacology*; D005964:Glucosyltransferases / Q000235:genetics / Q000378:metabolism*; D007210:Indoleacetic Acids / Q000378:metabolism*; D009154:Mutation; D054648:Protein Phosphatase 2 / Q000235:genetics / Q000378:metabolism*
D029681:Arabidopsis Proteins; D005419:Flavonoids; D005964:Glucosyltransferases; D007210:Indoleacetic Acids; D054648:Protein Phosphatase 2; C117013:AT5G57090 protein, Arabidopsis; C519657:RHM1 protein, Arabidopsis; C478612:RCN1 protein, Arabidopsis; C041477:3-hydroxyflavone