title: Root diffusion barrier control by a vasculature-derived peptide binding to the SGN3 receptor.
abstract: The root endodermis forms its extracellular diffusion barrier by developing ringlike impregnations called Casparian strips. A factor responsible for their establishment is the SCHENGEN3/GASSHO1 (SGN3/GSO1) receptor-like kinase. Its loss of function causes discontinuous Casparian strips. SGN3 also mediates endodermal overlignification of other Casparian strip mutants. Yet, without ligand, SGN3 function remained elusive. Here we report that schengen2 (sgn2) is defective in an enzyme sulfating peptide ligands. On the basis of this observation, we identified two stele-expressed peptides (CASPARIAN STRIP INTEGRITY FACTORS, CIF1/2) that complement sgn2 at nanomolar concentrations and induce Casparian strip mislocalization as well as overlignification-all of which depend on SGN3. Direct peptide binding to recombinant SGN3 identifies these peptides as SGN3 ligands. We speculate that CIF1/2-SGN3 is part of a barrier surveillance system, evolved to guarantee effective sealing of the supracellular Casparian strip network.
authors.affiliation: Department of Plant Molecular Biology, University of Lausanne, 1015 Lausanne, Switzerland.
authors.forename: Verónica G
authors.initials: VG
authors.lastname: Doblas
authors.affiliation: Gregor Mendel Institute, Austrian Academy of Sciences, Vienna Biocenter, Dr. Bohr-Gasse 3, 1030 Vienna, Austria.
authors.forename: Elwira
authors.initials: E
authors.lastname: Smakowska-Luzan
authors.affiliation: Department of Plant Molecular Biology, University of Lausanne, 1015 Lausanne, Switzerland.
authors.forename: Satoshi
authors.initials: S
authors.lastname: Fujita
authors.affiliation: Department of Plant Molecular Biology, University of Lausanne, 1015 Lausanne, Switzerland.
authors.forename: Julien
authors.initials: J
authors.lastname: Alassimone
authors.affiliation: Department of Plant Molecular Biology, University of Lausanne, 1015 Lausanne, Switzerland.
authors.forename: Marie
authors.initials: M
authors.lastname: Barberon
authors.affiliation: Protein Chemistry Core Facility, Research Institute of Molecular Pathology, Vienna Biocenter 1A, 1030 Vienna, Austria.
authors.forename: Mathias
authors.initials: M
authors.lastname: Madalinski
authors.affiliation: Gregor Mendel Institute, Austrian Academy of Sciences, Vienna Biocenter, Dr. Bohr-Gasse 3, 1030 Vienna, Austria. youssef.belkhadir@gmi.oeaw.ac.at niko.geldner@unil.ch.
authors.forename: Youssef
authors.initials: Y
authors.lastname: Belkhadir
authors.affiliation: Department of Plant Molecular Biology, University of Lausanne, 1015 Lausanne, Switzerland. youssef.belkhadir@gmi.oeaw.ac.at niko.geldner@unil.ch.
authors.forename: Niko
authors.initials: N
authors.lastname: Geldner
mesh_terms: D017360:Arabidopsis / Q000235:genetics / Q000378:metabolism*; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D004058:Diffusion; D008024:Ligands; D010455:Peptides / Q000378:metabolism; D018517:Plant Roots / Q000235:genetics / Q000378:metabolism*; D011485:Protein Binding; D011494:Protein Kinases / Q000235:genetics / Q000378:metabolism*; D015238:Sulfotransferases / Q000235:genetics / Q000378:metabolism*
chemical_list: D029681:Arabidopsis Proteins; D008024:Ligands; D010455:Peptides; D011494:Protein Kinases; C528620:GASSHO1 protein, Arabidopsis; D015238:Sulfotransferases; C039079:protein-tyrosine sulfotransferase