Abstract
Root hairs are single cells that develop by tip growth and are specialized in the absorption of nutrients. Their cell walls are composed of polysaccharides and hydroxyproline-rich glycoproteins (HRGPs) that include extensins (EXTs) and arabinogalactan-proteins (AGPs). Proline hydroxylation, an early posttranslational modification of HRGPs that is catalyzed by prolyl 4-hydroxylases (P4Hs), defines the subsequent O-glycosylation sites in EXTs (which are mainly arabinosylated) and AGPs (which are mainly arabinogalactosylated). We explored the biological function of P4Hs, arabinosyltransferases, and EXTs in root hair cell growth. Biochemical inhibition or genetic disruption resulted in the blockage of polarized growth in root hairs and reduced arabinosylation of EXTs. Our results demonstrate that correct O-glycosylation on EXTs is essential for cell-wall self-assembly and, hence, root hair elongation in Arabidopsis thaliana.
Publication types
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Research Support, Non-U.S. Gov't
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Research Support, U.S. Gov't, Non-P.H.S.
MeSH terms
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Arabidopsis / genetics
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Arabidopsis / growth & development
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Arabidopsis / metabolism*
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Arabidopsis Proteins / chemistry
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Arabidopsis Proteins / genetics
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Arabidopsis Proteins / metabolism*
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Arabinose / metabolism
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Carbohydrate Conformation
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Cell Wall / metabolism*
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Gene Expression Regulation, Plant
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Genes, Plant
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Glycoproteins / chemistry
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Glycoproteins / metabolism*
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Glycosylation
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Glycosyltransferases / genetics
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Glycosyltransferases / metabolism
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Hydroxylation
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Hydroxyproline / metabolism*
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Models, Biological
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Mutation
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Pentosyltransferases / chemistry
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Pentosyltransferases / metabolism
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Phenotype
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Plant Proteins / chemistry
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Plant Proteins / metabolism*
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Plant Roots / cytology
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Plant Roots / growth & development*
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Plant Roots / metabolism
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Polysaccharides / chemistry
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Procollagen-Proline Dioxygenase / genetics
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Procollagen-Proline Dioxygenase / metabolism*
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Proline / metabolism
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Protein Conformation
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Protein Processing, Post-Translational
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Protein Structure, Secondary
Substances
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Arabidopsis Proteins
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Glycoproteins
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Plant Proteins
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Polysaccharides
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extensin protein, plant
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Proline
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Arabinose
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Procollagen-Proline Dioxygenase
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Glycosyltransferases
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Pentosyltransferases
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arabinosyltransferase
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Hydroxyproline