title: Cell surface- and rho GTPase-based auxin signaling controls cellular interdigitation in Arabidopsis.
abstract: Auxin is a multifunctional hormone essential for plant development and pattern formation. A nuclear auxin-signaling system controlling auxin-induced gene expression is well established, but cytoplasmic auxin signaling, as in its coordination of cell polarization, is unexplored. We found a cytoplasmic auxin-signaling mechanism that modulates the interdigitated growth of Arabidopsis leaf epidermal pavement cells (PCs), which develop interdigitated lobes and indentations to form a puzzle-piece shape in a two-dimensional plane. PC interdigitation is compromised in leaves deficient in either auxin biosynthesis or its export mediated by PINFORMED 1 localized at the lobe tip. Auxin coordinately activates two Rho GTPases, ROP2 and ROP6, which promote the formation of complementary lobes and indentations, respectively. Activation of these ROPs by auxin occurs within 30 s and depends on AUXIN-BINDING PROTEIN 1. These findings reveal Rho GTPase-based auxin-signaling mechanisms, which modulate the spatial coordination of cell expansion across a field of cells.
authors.affiliation: Center for Plant Cell Biology, Department of Botany and Plant Sciences, University of California, Riverside, CA 92521, USA.
authors.forename: Tongda
authors.initials: T
authors.lastname: Xu
authors.forename: Mingzhang
authors.initials: M
authors.lastname: Wen
authors.forename: Shingo
authors.initials: S
authors.lastname: Nagawa
authors.forename: Ying
authors.initials: Y
authors.lastname: Fu
authors.forename: Jin-Gui
authors.initials: JG
authors.lastname: Chen
authors.forename: Ming-Jing
authors.initials: MJ
authors.lastname: Wu
authors.forename: Catherine
authors.initials: C
authors.lastname: Perrot-Rechenmann
authors.forename: Jiří
authors.initials: J
authors.lastname: Friml
authors.forename: Alan M
authors.initials: AM
authors.lastname: Jones
authors.forename: Zhenbiao
authors.initials: Z
authors.lastname: Yang
mesh_terms: D017360:Arabidopsis / Q000166:cytology* / Q000378:metabolism*; D029681:Arabidopsis Proteins / Q000378:metabolism*; D002462:Cell Membrane / Q000378:metabolism; D048430:Cell Shape; D019204:GTP-Binding Proteins / Q000378:metabolism*; D007210:Indoleacetic Acids / Q000378:metabolism*; D020559:Monomeric GTP-Binding Proteins / Q000378:metabolism*; D018515:Plant Leaves / Q000166:cytology; D010940:Plant Proteins / Q000378:metabolism; D011956:Receptors, Cell Surface / Q000378:metabolism; D015398:Signal Transduction
chemical_list: D029681:Arabidopsis Proteins; D019204:GTP-Binding Proteins; D007210:Indoleacetic Acids; D020559:Monomeric GTP-Binding Proteins; D010940:Plant Proteins; D011956:Receptors, Cell Surface; C518506:ROP6 protein, Arabidopsis; C083846:auxin-binding protein 1; C499714:AT1G20090 protein, Arabidopsis