The organization pattern of root border-like cells of Arabidopsis is dependent on cell wall homogalacturonan.
Border-like cells are released by Arabidopsis (Arabidopsis thaliana) root tips as organized layers of several cells that remain attached to each other rather than completely detached from each other, as is usually observed in border cells of many species. Unlike border cells, cell attachment between border-like cells is maintained after their release into the external environment. To investigate the role of cell wall polysaccharides in the attachment and organization of border-like cells, we have examined their release in several well-characterized mutants defective in the biosynthesis of xyloglucan, cellulose, or pectin. Our data show that among all mutants examined, only quasimodo mutants (qua1-1 and qua2-1), which have been characterized as producing less homogalacturonan, had an altered border-like cell phenotype as compared with the wild type. Border-like cells in both lines were released as isolated cells separated from each other, with the phenotype being much more pronounced in qua1-1 than in qua2-1. Further analysis of border-like cells in the qua1-1 mutant using immunocytochemistry and a set of anti-cell wall polysaccharide antibodies showed that the loss of the wild-type phenotype was accompanied by (1) a reduction in homogalacturonan-JIM5 epitope in the cell wall of border-like cells, confirmed by Fourier transform infrared microspectrometry, and (2) the secretion of an abundant mucilage that is enriched in xylogalacturonan and arabinogalactan-protein epitopes, in which the cells are trapped in the vicinity of the root tip.
Durand
Caroline
C
Laboratoire de Glycobiologie et Matrice Extracellulaire Végétale, Unité Propre de Recherche et d'Enseignement Supérieur Associé 4358, Institut Fédératif de Recherche Multidisciplinaire sur les Peptides 23, Plate-Forme de Recherche en Imagerie Cellulaire de Haute Normandie, Université de Rouen, 76821 Mont Saint Aignan, France.
Vicré-Gibouin
Maïté
M
Follet-Gueye
Marie Laure
ML
Duponchel
Ludovic
L
Moreau
Myriam
M
Lerouge
Patrice
P
Driouich
Azeddine
A
D017360:Arabidopsis / Q000166:cytology* / Q000235:genetics / Q000378:metabolism; D029681:Arabidopsis Proteins / Q000235:genetics; D002473:Cell Wall / Q000235:genetics / Q000378:metabolism*; D005685:Galactans / Q000378:metabolism; D005936:Glucans / Q000032:analysis; D006602:Hexosyltransferases / Q000235:genetics; D006603:Hexuronic Acids / Q000378:metabolism; D007150:Immunohistochemistry; D009154:Mutation; D010368:Pectins / Q000032:analysis / Q000235:genetics / Q000378:metabolism*; D010641:Phenotype; D018517:Plant Roots / Q000166:cytology / Q000235:genetics / Q000378:metabolism; D017550:Spectroscopy, Fourier Transform Infrared; D014990:Xylans / Q000032:analysis
D029681:Arabidopsis Proteins; D005685:Galactans; D005936:Glucans; D006603:Hexuronic Acids; D014990:Xylans; C465879:xylogalacturonan; C029353:xyloglucan; D010368:Pectins; D006602:Hexosyltransferases; C508259:QUA1 protein, Arabidopsis; C005653:arabinogalactan; C003181:polygalacturonic acid