O-glycosylated cell wall proteins are essential in root hair growth

SILVIA M. VELASQUEZ; MARTINIANO M. RICARDI; JAVIER GLOAZZO DOROSZ1; PAULA V. FERNANDEZ; ALEJANDRO D. NADRA; LAERCIO POL-FACHIN; JACK EGELUND; SASCHA GILLE; JESPER HARHOL; MARINA CIANCIA; HUGO VERLI; MARKUS PAULY; ANTONY BACIC; CARL ERIK OLSEN; PETER ULVSKOV; BENT LARSEN PETERSEN; CHRIS SOMERVILLE; NORBERTO D. IUSEM; JOSE M. ESTEVEZ

SCIENCE

AMER ASSOC ADVANCEMENT SCIENCE

Año: 2011 p. 1401 - 1403

0036-8075

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 post-translational modification of HRGPs that is catalyzed by prolyl 4-hydroxylases (P4Hs), defines the subsequent O-glycosylation sites in EXTs (mainly arabinosylation) and AGPs (arabinogalactosylation). Here, 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.