WRKY23 is a component of the transcriptional network mediating auxin feedback on PIN polarity Journal Article

Author(s): Prat, Tomas; Hajny, Jakub; Grunewald, Wim; Vasileva, Mina; Molnar, Gergely; Tejos, Ricardo; Schmid, Markus; Sauer, Michael; Friml, Jiří
Article Title: WRKY23 is a component of the transcriptional network mediating auxin feedback on PIN polarity
Affiliation IST Austria
Abstract: Auxin is unique among plant hormones due to its directional transport that is mediated by the polarly distributed PIN auxin transporters at the plasma membrane. The canalization hypothesis proposes that the auxin feedback on its polar flow is a crucial, plant-specific mechanism mediating multiple self-organizing developmental processes. Here, we used the auxin effect on the PIN polar localization in Arabidopsis thaliana roots as a proxy for the auxin feedback on the PIN polarity during canalization. We performed microarray experiments to find regulators of this process that act downstream of auxin. We identified genes that were transcriptionally regulated by auxin in an AXR3/IAA17- and ARF7/ARF19-dependent manner. Besides the known components of the PIN polarity, such as PID and PIP5K kinases, a number of potential new regulators were detected, among which the WRKY23 transcription factor, which was characterized in more detail. Gain- and loss-of-function mutants confirmed a role for WRKY23 in mediating the auxin effect on the PIN polarity. Accordingly, processes requiring auxin-mediated PIN polarity rearrangements, such as vascular tissue development during leaf venation, showed a higher WRKY23 expression and required the WRKY23 activity. Our results provide initial insights into the auxin transcriptional network acting upstream of PIN polarization and, potentially, canalization-mediated plant development.
Journal Title: PLoS Genetics
Volume: 14
Issue 1
ISSN: 1553-7404
Publisher: Public Library of Science  
Publication Place: United States
Date Published: 2018-01-29
Start Page: Article number: e1007177
Copyright Statement: CC BY
Sponsor: This work was supported by the European Research Council (project ERC-2011-StG 20101109-PSDP). WG was a postdoctoral fellow of the Research Foundation Flanders.
DOI: 10.1371/journal.pgen.1007177
Notes: We thank D. Weigel for support with microarray analysis; F. Coppens for assistance with the qRT-PCR analysis and M. De Cock and M. Abas for help in preparing the manuscript. We gratefully acknowledge the Nottingham Arabidopsis Stock Center (NASC) for providing mutant lines.
Open access: yes (OA journal)