title: Cell wall pectic (1-->4)-beta-d-galactan marks the acceleration of cell elongation in the Arabidopsis seedling root meristem.
abstract: Here we demonstrate that the pectic rhamnogalacturonan-I-associated LM5 (1-->4)-beta-d-galactan epitope occurs in a restricted manner at the root surface of intact Arabidopsis seedlings. The root surface occurrence of (1-->4)-beta-d-galactan marks the transition zone at or near the onset of rapid cell elongation and the epitope is similarly restricted in occurrence in epidermal, cortical and endodermal cell walls. The extent of surface (1-->4)-beta-d-galactan occurrence is reduced in response to genetic mutations (stp-1, ctr-1) and hormone applications that reduce root cell elongation. In contrast, the application of the arabinogalactan-protein (AGP) binding beta-glucosyl Yariv reagent (betaGlcY) that disrupts cell elongation results in the persistence of (1-->4)-beta-d-galactan at the root surface and in epidermal, cortical and endodermal cell walls. This latter observation indicates that modulation of pectic (1-->4)-beta-d-galactan may be an event downstream of AGP function during cell expansion in the Arabidopsis seedling root.
authors.affiliation: Centre for Plant Sciences, University of Leeds, Leeds LS2 9JT, UK.
authors.forename: Lesley
authors.initials: L
authors.lastname: McCartney
authors.forename: Clare G
authors.initials: CG
authors.lastname: Steele-King
authors.forename: Emillie
authors.initials: E
authors.lastname: Jordan
authors.forename: J Paul
authors.initials: JP
authors.lastname: Knox
mesh_terms: D017360:Arabidopsis / Q000235:genetics / Q000254:growth & development* / Q000378:metabolism; D002455:Cell Division / Q000187:drug effects / Q000502:physiology; D002473:Cell Wall / Q000378:metabolism*; D003583:Cytokinins / Q000494:pharmacology; D005685:Galactans / Q000037:antagonists & inhibitors / Q000378:metabolism*; D005960:Glucosides / Q000494:pharmacology; D007210:Indoleacetic Acids / Q000494:pharmacology; D018519:Meristem / Q000187:drug effects / Q000254:growth & development* / Q000378:metabolism; D009088:Mucoproteins / Q000378:metabolism; D009154:Mutation; D010368:Pectins / Q000378:metabolism*; D010696:Phloroglucinol / Q000031:analogs & derivatives* / Q000494:pharmacology; D010937:Plant Growth Regulators / Q000494:pharmacology; D010940:Plant Proteins; D018517:Plant Roots / Q000187:drug effects / Q000254:growth & development / Q000378:metabolism
chemical_list: C411147:1,4-beta-galactan; D003583:Cytokinins; D005685:Galactans; D005960:Glucosides; D007210:Indoleacetic Acids; D009088:Mucoproteins; D010937:Plant Growth Regulators; D010940:Plant Proteins; C104977:Yariv reagent; C006619:arabinogalactan proteins; C042491:rhamnogalacturonan I; D010368:Pectins; D010696:Phloroglucinol