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.

Department of Biology geislerLab University of Fribourg Fribourg Switzerland

Institute of Chemistry University of Zurich Zurich Switzerland

Institute of Experimental Botany Academy of Sciences of the Czech Republic Prague Czech Republic

Institute of Plant and Microbial Biology University of Zurich Zurich Switzerland

Institute of Science and Technology Austria Am Campus 1 3400 Klosterneuburg Austria

Mendel Centre for Plant Genomics and Proteomics Central European Institute of Technology Masaryk University Kamenice 5 CZ 625 00 Brno Czech Republic

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Adamowski M. & Friml J. PIN-dependent auxin transport: action, regulation, and evolution. Plant Cell 27, 20–32, doi: 10.1105/tpc.114.134874 (2015). PubMed DOI PMC

Pencik A. et al.. Regulation of auxin homeostasis and gradients in Arabidopsis roots through the formation of the indole-3-acetic acid catabolite 2-oxindole-3-acetic acid. Plant Cell 25, 3858–3870, doi: 10.1105/tpc.113.114421 (2013). PubMed DOI PMC

Zažímalová E., Murphy A. S., Yang H., Hoyerova K. & Hosek P. Auxin transporters - why so many? Cold Spring Harbor Perspectives in Biology 2, doi: a00155210.1101/cshperspect.a001552 (2010). PubMed PMC

Geisler M. et al.. Cellular efflux of auxin catalyzed by the Arabidopsis MDR/PGP transporter AtPGP1. Plant J. 44, 179–194 (2005). PubMed

Blakeslee J. J. et al.. Interactions among PIN-FORMED and P-glycoprotein auxin transporters in Arabidopsis. Plant Cell 19, 131–147, doi: 10.1105/tpc.106.040782 (2007). PubMed DOI PMC

Bouchard R. et al.. Immunophilin-like TWISTED DWARF1 modulates auxin efflux activities of Arabidopsis P-glycoproteins. J. Biol. Chem. 281, 30603–30612, doi: 10.1074/jbc.M604604200 (2006). PubMed DOI

Bailly A. et al.. Modulation of P-glycoproteins by auxin transport inhibitors is mediated by interaction with immunophilins. J. Biol. Chem. 283, 21817–21826, doi: 10.1074/jbc.M709655200 (2008). PubMed DOI

Mravec J. et al.. Interaction of PIN and PGP transport mechanisms in auxin distribution-dependent development. Development 135, 3345–3354, doi: 10.1242/dev.021071 (2008). PubMed DOI

Friml J. et al.. Efflux-dependent auxin gradients establish the apical-basal axis of Arabidopsis. Nature 426, 147–153, doi: 10.1038/nature02085 (2003). PubMed DOI

Wisniewska J. et al.. Polar PIN localization directs auxin flow in plants. Science 312, 883–883, doi: 10.1126/science.1121356 (2006). PubMed DOI

Petrasek J. et al.. PIN proteins perform a rate-limiting function in cellular auxin efflux. Science 312, 914–918, doi: 10.1126/science.1123542 (2006). PubMed DOI

Blilou I. et al.. The PIN auxin efflux facilitator network controls growth and patterning in Arabidopsis roots. Nature 433, 39–44, doi: 10.1038/nature03184 (2005). PubMed DOI

Vieten A., Sauer M., Brewer P. B. & Friml J. Molecular and cellular aspects of auxin-transport-mediated development. Trends Plant Sci. 12, 160–168, doi: 10.1016/j.tplants.2007.03.006 (2007). PubMed DOI

Bennett S. R. M., Alvarez J., Bossinger G. & Smyth D. R. Morphogenesis in pinoid mutants of Arabidopsis thaliana. Plant J. 8, 505–520, doi: 10.1046/j.1365-313X.1995.8040505.x (1995). DOI

Christensen S. K., Dagenais N., Chory J. & Weigel D. Regulation of auxin response by the protein kinase PINOID. Cell 100, 469–478, doi: 10.1016/s0092-8674(00)80682-0 (2000). PubMed DOI

Benjamins R., Quint A., Weijers D., Hooykaas P. & Offringa R. The PINOID protein kinase regulates organ development in Arabidopsis by enhancing polar auxin transport. Development 128, 4057–4067 (2001). PubMed

Henrichs S. et al.. Regulation of ABCB1/PGP1-catalysed auxin transport by linker phosphorylation. Embo J. 31, 2965–2980, doi: 10.1038/emboj.2012.120 (2012). PubMed DOI PMC

Shin H. et al.. Complex regulation of Arabidopsis AGR1/PIN2-mediated root gravitropic response and basipetal auxin transport by cantharidin-sensitive protein phosphatases. Plant J. 42, 188–200, doi: 10.1111/j.1365-313X.2005.02369.x (2005). PubMed DOI

Garbers C., DeLong A., Deruere J., Bernasconi P. & Soll D. A mutation in protein phosphatase 2A regulatory subunit A affects auxin transport in Arabidopsis. Embo J. 15, 2115–2124 (1996). PubMed PMC

Friml J. et al.. A PINOID-dependent binary switch in apical-basal PIN polar targeting directs auxin efflux. Science 306, 862–865 (2004). PubMed

Zourelidou M. et al.. Auxin efflux by PIN-FORMED proteins is activated by two different protein kinases, D6 PROTEIN KINASE and PINOID. Elife 3, doi: 10.7554/eLife.02860 (2014). PubMed DOI PMC

Michniewicz M. et al.. Antagonistic regulation of PIN phosphorylation by PP2A and PINOID directs auxin flux. Cell 130, 1044–1056 (2007). PubMed

Huang F. et al.. Phosphorylation of conserved PIN motifs directs Arabidopsis PIN1 polarity and auxin transport. Plant Cell 22, 1129–1142, doi: 10.1105/tpc.109.072678 (2010). PubMed DOI PMC

Sukumar P., Edwards K. S., Rahman A., DeLong A. & Muday G. K. PINOID kinase regulates root gravitropism through modulation of PIN2-dependent basipetal auxin transport in Arabidopsis. Plant Physiol. 150, 722–735, doi: 10.1104/pp.108.131607 (2009). PubMed DOI PMC

Rashotte A. M., DeLong A. & Muday G. K. Genetic and chemical reductions in protein phosphatase activity alter auxin transport, gravity response, and lateral root growth. Plant Cell 13, 1683–1697 (2001). PubMed PMC

Muday G. K. et al.. RCN1-regulated phosphatase activity and EIN2 modulate hypocotyl gravitropism by a mechanism that does not require ethylene signaling. Plant Physiol. 141, 1617–1629, doi: 10.1104/pp.106.083212 (2006). PubMed DOI PMC

Taylor L. P. & Grotewold E. Flavonoids as developmental regulators. Curr. Op. Plant Biol. 8, 317–323 (2005). PubMed

Mo Y. Y., Nagel C. & Taylor L. P. Biochemical complementation of chalcone synthase mutants defines a role for flavonols in functional pollen. Proc. Natl. Acad. Sci. USA 89, 7213–7217 (1992). PubMed PMC

Lepiniec L. et al.. Genetics and biochemistry of seed flavonoids. Annu. Rev. Plant Biol. 57, 405–430 (2006). PubMed

Veit M. & Pauli G. F. Major flavonoids from Arabidopsis thaliana leaves. J. Nat. Prod. 62, 1301–1303 (1999). PubMed

Koornneef M. Mutations affecting the testa color in Arabidopsis. Arabidopsis Inf Serv 19, 113–115 (1990).

Shirley B. W. et al.. Analysis of Arabidopsis mutants deficient in flavonoid biosynthesis. Plant J. 8, 659–671 (1995). PubMed

Buer C. S. & Muday G. K. The transparent testa4 mutation prevents flavonoid synthesis and alters auxin transport and the response of Arabidopsis roots to gravity and light. Plant Cell 16, 1191–1205 (2004). PubMed PMC

Peer W. A. et al.. Variation in expression and protein localization of the PIN family of auxin efflux facilitator proteins in flavonoid mutants with altered auxin transport in Arabidopsis thaliana. Plant Cell 16, 1898–1911 (2004). PubMed PMC

Jacobs M. & Rubery P. H. Naturally-Occurring Auxin Transport Regulators. Science 241, 346–349 (1988). PubMed

Santelia D. et al.. Flavonoids redirect PIN-mediated polar auxin fluxes during root gravitropic responses. J. Biol. Chem. 283, 31218–31226, doi: 10.1074/jbc.M710122200 (2008). PubMed DOI PMC

Diet A. et al.. The Arabidopsis root hair cell wall formation mutant lrx1 is suppressed by mutations in the RHM1 gene encoding a UDP-L-rhamnose synthase. Plant Cell 18, 1630–1641 (2006). PubMed PMC

Ringli C. et al.. The modified flavonol glycosylation profile in the Arabidopsis rol1 mutants results in alterations in plant growth and cell shape formation. Plant Cell 20, 1470–1481 (2008). PubMed PMC

Kuhn B. M., Geisler M., Bigler L. & Ringli C. Flavonols accumulate asymmetrically and affect auxin transport in Arabidopsis. Plant Physiol. 156, 585–595, doi: 10.1104/pp.111.175976 (2011). PubMed DOI PMC

Stracke R. et al.. Differential regulation of closely related R2R3-MYB transcription factors controls flavonol accumulation in different parts of the Arabidopsis thaliana seedling. Plant J. 50, 660–677 (2007). PubMed PMC

Kuhn B. M. et al.. 7-rhamnosylated flavonols modulate homeostasis of the plant hormone auxin and affect plant development. J. Biol. Chem. 291, 5385–5395, doi: 10.1074/jbc.M115.701565 (2016). PubMed DOI PMC

Larsen P. B. & Cancel J. D. Enhanced ethylene responsiveness in the Arabidopsis eer1 mutant results from a loss-of-function mutation in the protein phosphatase 2A A regulatory subunit, RCN1. Plant J. 34, 709–718, doi: 10.1046/j.1365-313X.2003.01762.x (2003). PubMed DOI

Li Y. M. & Casida J. E. Cantharidin-binding protein - identification as protein phosphatase-2a. Proc. Natl. Acad. Sci. USA 89, 11867–11870, doi: 10.1073/pnas.89.24.11867 (1992). PubMed DOI PMC

Pereira S. R., Vasconcelos V. M. & Antunes A. The phosphoprotein phosphatase family of Ser/Thr phosphatases as principal targets of naturally occurring toxins. Crit. Rev. Toxicol. 41, 83–110, doi: 10.3109/10408444.2010.515564 (2011). PubMed DOI

Deruere J., Jackson K., Garbers C., Soll D. & DeLong A. The RCN1-encoded A subunit of protein phosphatase 2A increases phosphatase activity in vivo. Plant J. 20, 389–399, doi: 10.1046/j.1365-313x.1999.00607.x (1999). PubMed DOI

Kleine-Vehn J. et al.. Cellular and molecular requirements for polar PIN targeting and transcytosis in plants. Mol. Plant 1, 1056–1066, doi: 10.1093/mp/ssn062 (2008). PubMed DOI

Grabov A. et al.. Morphometric analysis of root shape. New Phytol. 165, 641–651, doi: 10.1111/j.1469-8137.2004.01258.x (2005). PubMed DOI

Peer W. A. et al.. Flavonoid accumulation patterns of transparent testa mutants of Arabidopsis. Plant Physiol. 126, 536–548 (2001). PubMed PMC

Rahman A. et al.. Gravitropism of Arabidopsis thaliana roots requires the polarization of PIN2 toward the root tip in meristematic cortical cells. Plant Cell 22, 1762–1776, doi: 10.1105/tpc.110.075317 (2010). PubMed DOI PMC

Barbosa I. C. R., Zourelidou M., Willige B. C., Weller B. & Schwechheimer C. D6 PROTEIN KINASE activates auxin transport-dependent growth and PIN-FORMED phosphorylation at the plasma membrane. Dev. Cell 29, 674–685, doi: 10.1016/j.devcel.2014.05.006 (2014). PubMed DOI

Santner A. A. & Watson J. C. The WAG1 and WAG2 protein kinases negatively regulate root waving in Arabidopsis. Plant J. 45, 752–764, doi: 10.1111/j.1365-313X.2005.02641.x (2006). PubMed DOI

Peer W. A., Cheng Y. & Murphy A. S. Evidence of oxidative attenuation of auxin signalling. J. Exp. Bot. 64, 2629–2639, doi: 10.1093/jxb/ert152 (2013). PubMed DOI

Watkins J. M., Hechler P. J. & Muday G. K. Ethylene-induced flavonol accumulation in guard cells suppresses reactive oxygen species and moderates stomatal aperture. Plant Physiol. 164, 1707–1717, doi: 10.1104/pp.113.233528 (2014). PubMed DOI PMC

Maloney G. S., DiNapoli K. T. & Muday G. K. The anthocyanin reduced tomato mutant demonstrates the role of flavonols in tomato lateral root and root hair development. Plant Physiol. 166, 614–U254, doi: 10.1104/pp.114.240507 (2014). PubMed DOI PMC

Stintzi A. & Browse J. The Arabidopsis male-sterile mutant, opr3, lacks the 12-oxophytodienoic acid reductase required for jasmonate synthesis. Proc. Natl. Acad. Sci. USA 97, 10625–10630, doi: 190264497 [pii] 10.1073/pnas.190264497 (2000). PubMed DOI PMC

Gleave A. P. A versatile binary vector system with a T-DNA organizational structure conducive to efficient integration of cloned DNA into the plant genome. Plant. Mol. Biol. 20, 1203–1207 (1992). PubMed

Horiguchi G., Fujikura U., Ferjani A., Ishikawa N. & Tsukaya H. Large-scale histological analysis of leaf mutants using two simple leaf observation methods: identification of novel genetic pathways governing the size and shape of leaves. Plant J. 48, 638–644 (2006). PubMed

Sauer M. et al.. Canalization of auxin flow by Aux/IAA-ARF-dependent feedback regulation of PIN polarity. Genes Dev. 20, 2902–2911, doi: 10.1101/gad.390806 (2006). PubMed DOI PMC

Paciorek T. et al.. Auxin inhibits endocytosis and promotes its own efflux from cells. Nature 435, 1251–1256, doi: 10.1038/nature03633 (2005). PubMed DOI

Dobrev P. I. & Vankova R. Quantification of abscisic Acid, cytokinin, and auxin content in salt-stressed plant tissues. Meth. Mol. Biol. 913, 251–261, doi: 10.1007/978-1-61779-986-0_17 (2012). PubMed DOI

Dobrev P. I. & Kaminek M. Fast and efficient separation of cytokinins from auxin and abscisic acid and their purification using mixed-mode solid-phase extraction. J. Chromatogr. A 950, 21–29, doi: Pii s0021-9673(02)00024-9 (2002). PubMed

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