Relevance of prolyl-hydroxylation and O-glycosylation on HRGPs that modulates cell elongation in the model plant Arabidopsis thaliana

MARTINIANO M. RICARDI; JAVIER GLOAZZO DOROSZ; CECILIA BORASSI; PAULA X. ARATA; MARINA CIANCIA; JORGE P. MUSCHIETTI; JOSÉ M. ESTEVEZ

Congreso; First Argentinean Symposium of Glycobiology "GlycoAR 2014"; 2014

Recent findings demonstrated that proline hydroxylation and subsequent O-glycosylation of several 4-hydroxyproline rich glycoproteins (HRGP) plays an important role in root hair elongation (Velasquez, et al. Science 2011). Root hair growth is achieved through single cell elongation and is impaired by prolil-4-hydroxilases inhibitors (iP4Hs) like DP and EDHB. Our current work is now focusing on other cell elongation models like dark-growth hypocotyls and pollen tubes. So far we have been able to demonstrate that the same P4Hs inhibitors are able to diminish hypocotyl elongation and also impair pollen tubes growth. Hypocotyl as well as pollen tubes lengths in iP4Hs treated cells were diminished in a dose-dependent way. As suggested by this pharmacological approach we are also testing if genetic disruptions of P4Hs may have an impact in both hypocotyls and pollen tubes systems. Plants harboring mutations on several P4Hs genes showed lower levels of hydroxyproline in whole seedlings when compared to Wt type Col-0 leading us to conclude that these genes encode for functional enzymes. Due to gene redundancy of P4Hs we are now analyzing multiple mutants in both cell elongation systems. We speculate that this deficient prolyl-hydroxylation would modify the subsequent O-glycosylation status on the cell wall HRGPs that would affect cell elongation.