title: Canalization of auxin flow by Aux/IAA-ARF-dependent feedback regulation of PIN polarity.
abstract: Plant development is characterized by a profound ability to regenerate and form tissues with new axes of polarity. An unsolved question concerns how the position within a tissue and cues from neighboring cells are integrated to specify the polarity of individual cells. The canalization hypothesis proposes a feedback effect of the phytohormone auxin on the directionality of intercellular auxin flow as a means to polarize tissues. Here we identify a cellular and molecular mechanism for canalization. Local auxin application, wounding, or auxin accumulation during de novo organ formation lead to rearrangements in the subcellular polar localization of PIN auxin transport components. This auxin effect on PIN polarity is cell-specific, does not depend on PIN transcription, and involves the Aux/IAA-ARF (indole-3-acetic acid-auxin response factor) signaling pathway. Our data suggest that auxin acts as polarizing cue, which links individual cell polarity with tissue and organ polarity through control of PIN polar targeting. This feedback regulation provides a conceptual framework for polarization during multiple regenerative and patterning processes in plants.
authors.affiliation: Center for Plant Molecular Biology (ZMBP), University Tübingen, 72076 Tübingen, Germany.
authors.forename: Michael
authors.initials: M
authors.lastname: Sauer
authors.forename: Jozef
authors.initials: J
authors.lastname: Balla
authors.forename: Christian
authors.initials: C
authors.lastname: Luschnig
authors.forename: Justyna
authors.initials: J
authors.lastname: Wisniewska
authors.forename: Vilém
authors.initials: V
authors.lastname: Reinöhl
authors.forename: Jirí
authors.initials: J
authors.lastname: Friml
authors.forename: Eva
authors.initials: E
authors.lastname: Benková
mesh_terms: D017360:Arabidopsis / Q000378:metabolism; D029681:Arabidopsis Proteins / Q000378:metabolism; D018506:Gene Expression Regulation, Plant; D007210:Indoleacetic Acids / Q000737:chemistry* / Q000378:metabolism; D018532:Pisum sativum; D018524:Phototropism; D010937:Plant Growth Regulators; D018521:Plant Physiological Phenomena; D010940:Plant Proteins / Q000502:physiology*; D018517:Plant Roots / Q000378:metabolism; D015398:Signal Transduction; D014158:Transcription, Genetic
chemical_list: D029681:Arabidopsis Proteins; D007210:Indoleacetic Acids; D010937:Plant Growth Regulators; D010940:Plant Proteins; C030737:indoleacetic acid