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Updated: May 31, 2026

High Resolution Quantification of Crystalline Cellulose Accumulation in Arabidopsis Roots to Monitor Tissue-specific Cell Wall Modifications
Published on: May 10, 2016
O-glycosylated cell wall proteins are essential in root hair growth
Silvia M Velasquez1, Martiniano M Ricardi, Javier Gloazzo Dorosz
1Instituto de Fisiología, Biología Molecular y Neurociencias-Consejo Nacional de Investigaciones Científicas y Técnicas (IFIByNE-CONICET), Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Buenos Aires C1428EGA, Argentina.
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.
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