Plant proline hydroxylation mediated by P4H2,5,13 and subsequent linked O-glycosylation on root hair specific extensins (rhEXT) is crucial and required for the elongation phase during polarized growth

J. M. ESTEVEZ, S. M. VELASQUEZ, M. M. RICARDI, N. D. IUSEM.

Alejandria, Egipto

Congreso; BioVision Alexandria 2010; 2010

TWAS

From 13 plant prolyl 4-hydroxylases (P4Hs) present in Arabidopsis genome only few of them are highly expressed in roots. Pharmacological experiments indicated that apical cell expansion in the elongation phase of root hairs are partially blocked by binding of a specific inhibitor a,a-Dipyridil (a,a-DP) of prolyl 4-hydroxylases (P4Hs) to the catalytic site of these enzymes. In addition, gene disruption of single P4Hs highly expressed in root (p4h2, p4h5, and p4h13) resulted in drastically reduced root hair lengths. Dual subcellular localization in the ER and medial-Golgi suggests that hydroxylation of HRGP substrates would occur in both organelles. This data suggests that specifically the deficiency in hydroxylation mediated by rhP4Hs and subsequent O-glycosylation on putative Hydroxyproline Rich Glycoproteins (HRGPs) is an important structural factor for reduced elongation in polarized growth on root hairs.