title: Xyloglucan, galactomannan, glucuronoxylan, and rhamnogalacturonan I do not have identical structures in soybean root and root hair cell walls.
abstract: Chemical analyses and glycome profiling demonstrate differences in the structures of the xyloglucan, galactomannan, glucuronoxylan, and rhamnogalacturonan I isolated from soybean ( Glycine max ) roots and root hair cell walls. The root hair is a plant cell that extends only at its tip. All other root cells have the ability to grow in different directions (diffuse growth). Although both growth modes require controlled expansion of the cell wall, the types and structures of polysaccharides in the walls of diffuse and tip-growing cells from the same plant have not been determined. Soybean (Glycine max) is one of the few plants whose root hairs can be isolated in amounts sufficient for cell wall chemical characterization. Here, we describe the structural features of rhamnogalacturonan I, rhamnogalacturonan II, xyloglucan, glucomannan, and 4-O-methyl glucuronoxylan present in the cell walls of soybean root hairs and roots stripped of root hairs. Irrespective of cell type, rhamnogalacturonan II exists as a dimer that is cross-linked by a borate ester. Root hair rhamnogalacturonan I contains more neutral oligosaccharide side chains than its root counterpart. At least 90% of the glucuronic acid is 4-O-methylated in root glucuronoxylan. Only 50% of this glycose is 4-O-methylated in the root hair counterpart. Mono O-acetylated fucose-containing subunits account for at least 60% of the neutral xyloglucan from root and root hair walls. By contrast, a galacturonic acid-containing xyloglucan was detected only in root hair cell walls. Soybean homologs of the Arabidopsis xyloglucan-specific galacturonosyltransferase are highly expressed only in root hairs. A mannose-rich polysaccharide was also detected only in root hair cell walls. Our data demonstrate that the walls of tip-growing root hairs cells have structural features that distinguish them from the walls of other roots cells.
authors.affiliation: Complex Carbohydrate Research Center, University of Georgia, Athens, GA, 30602, USA.
authors.forename: Artur
authors.initials: A
authors.lastname: Muszyński
authors.affiliation: Complex Carbohydrate Research Center, University of Georgia, Athens, GA, 30602, USA. mao@ccrc.uga.edu.
authors.forename: Malcolm A
authors.initials: MA
authors.lastname: O'Neill
authors.affiliation: Complex Carbohydrate Research Center, University of Georgia, Athens, GA, 30602, USA.
authors.forename: Easwaran
authors.initials: E
authors.lastname: Ramasamy
authors.affiliation: Complex Carbohydrate Research Center, University of Georgia, Athens, GA, 30602, USA.
authors.forename: Sivakumar
authors.initials: S
authors.lastname: Pattathil
authors.affiliation: Complex Carbohydrate Research Center, University of Georgia, Athens, GA, 30602, USA.
authors.forename: Utku
authors.initials: U
authors.lastname: Avci
authors.affiliation: Complex Carbohydrate Research Center, University of Georgia, Athens, GA, 30602, USA.
authors.forename: Maria J
authors.initials: MJ
authors.lastname: Peña
authors.affiliation: Divisions of Plant Science and Biochemistry, National Center for Soybean Biotechnology, University of Missouri, Columbia, MO, 65211, USA.|Department of Microbiology and Plant Biology, University of Oklahoma, Norman, OK, 73019, USA.
authors.forename: Marc
authors.initials: M
authors.lastname: Libault
authors.affiliation: Divisions of Plant Science and Biochemistry, National Center for Soybean Biotechnology, University of Missouri, Columbia, MO, 65211, USA.
authors.forename: Md Shakhawat
authors.initials: MS
authors.lastname: Hossain
authors.affiliation: Divisions of Plant Science and Biochemistry, National Center for Soybean Biotechnology, University of Missouri, Columbia, MO, 65211, USA.|Southern Alberta Mass Spectrometry Center, University of Calgary, Alberta, T2N 4N1, Canada.
authors.forename: Laurent
authors.initials: L
authors.lastname: Brechenmacher
authors.affiliation: Complex Carbohydrate Research Center, University of Georgia, Athens, GA, 30602, USA.|Department of Biochemistry and Molecular Biology, University of Georgia, Athens, GA, 30602, USA.
authors.forename: William S
authors.initials: WS
authors.lastname: York
authors.affiliation: Instituto de Informática, Universidade Federal de Goiás, Goiânia, 74001-970, Brazil.
authors.forename: Rommel M
authors.initials: RM
authors.lastname: Barbosa
authors.affiliation: Complex Carbohydrate Research Center, University of Georgia, Athens, GA, 30602, USA.|Department of Plant Biology, University of Georgia, Athens, GA, 30602, USA.
authors.forename: Michael G
authors.initials: MG
authors.lastname: Hahn
authors.affiliation: Divisions of Plant Science and Biochemistry, National Center for Soybean Biotechnology, University of Missouri, Columbia, MO, 65211, USA.
authors.forename: Gary
authors.initials: G
authors.lastname: Stacey
authors.affiliation: Complex Carbohydrate Research Center, University of Georgia, Athens, GA, 30602, USA.
authors.forename: Russell W
authors.initials: RW
authors.lastname: Carlson
mesh_terms: D002473:Cell Wall / Q000737:chemistry*; D005690:Galactose / Q000031:analogs & derivatives; D005936:Glucans / Q000737:chemistry*; D008351:Mannans / Q000737:chemistry*; D010368:Pectins / Q000737:chemistry*; D018517:Plant Roots / Q000737:chemistry*; D013025:Glycine max / Q000737:chemistry*; D014990:Xylans / Q000737:chemistry*
chemical_list: D005936:Glucans; D008351:Mannans; D014990:Xylans; C042491:rhamnogalacturonan I; C012990:galactomannan; C029353:xyloglucan; C038910:glucuronoxylan; D010368:Pectins; D005690:Galactose
keywords: Arabinogalactan protein (AGP); Cell wall; Extensin; Hemicellulose; Pectin; Root; Root hair