title: Complex regulation of prolyl-4-hydroxylases impacts root hair expansion.
abstract: Root hairs are single cells that develop by tip growth, a process shared with pollen tubes, axons, and fungal hyphae. However, structural plant cell walls impose constraints to accomplish tip growth. In addition to polysaccharides, plant cell walls are composed of hydroxyproline-rich glycoproteins (HRGPs), which include several groups of O-glycoproteins, including extensins (EXTs). Proline hydroxylation, an early post-translational modification (PTM) of HRGPs catalyzed by prolyl 4-hydroxylases (P4Hs), defines their subsequent O-glycosylation sites. In this work, our genetic analyses prove that P4H5, and to a lesser extent P4H2 and P4H13, are pivotal for root hair tip growth. Second, we demonstrate that P4H5 has in vitro preferred specificity for EXT substrates rather than for other HRGPs. Third, by P4H promoter and protein swapping approaches, we show that P4H2 and P4H13 have interchangeable functions but cannot replace P4H5. These three P4Hs are shown to be targeted to the secretory pathway, where P4H5 forms dimers with P4H2 and P4H13. Finally, we explore the impact of deficient proline hydroxylation on the cell wall architecture. Taken together, our results support a model in which correct peptidyl-proline hydroxylation on EXTs, and possibly in other HRGPs, is required for proper cell wall self-assembly and hence root hair elongation in Arabidopsis thaliana.
authors: Instituto de Fisiología, Biología Molecular y Neurociencias (IFIBYNE-CONICET), Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Buenos Aires C1428EGA, Argentina.
authors: Silvia M
authors: SM
authors: Velasquez
authors: Instituto de Fisiología, Biología Molecular y Neurociencias (IFIBYNE-CONICET), Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Buenos Aires C1428EGA, Argentina.
authors: Martiniano M
authors: MM
authors: Ricardi
authors: VKR Research Centre, Department of Plant and Environmental Sciences, University of Copenhagen, DK-1871 Frederiksberg C, Denmark.
authors: Christian Peter
authors: CP
authors: Poulsen
authors: Joint BioEnergy Institute, Feedstocks Division, Lawrence Berkeley National Laboratory, 5885 Hollis Street, Emeryville, CA 94608, USA.
authors: Ai
authors: A
authors: Oikawa
authors: VKR Research Centre, Department of Plant and Environmental Sciences, University of Copenhagen, DK-1871 Frederiksberg C, Denmark.
authors: Adiphol
authors: A
authors: Dilokpimol
authors: Copenhagen Center for Glycomics, Department of Cellular and Molecular, Faculty of Health and Medical Sciences, University of Copenhagen, DK-2200 Copenhagen N, Denmark.
authors: Adnan
authors: A
authors: Halim
authors: Instituto de Fisiología, Biología Molecular y Neurociencias (IFIBYNE-CONICET), Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Buenos Aires C1428EGA, Argentina.
authors: Silvina
authors: S
authors: Mangano
authors: Instituto de Fisiología, Biología Molecular y Neurociencias (IFIBYNE-CONICET), Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Buenos Aires C1428EGA, Argentina.
authors: Silvina Paola
authors: SP
authors: Denita Juarez
authors: Instituto de Fisiología, Biología Molecular y Neurociencias (IFIBYNE-CONICET), Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Buenos Aires C1428EGA, Argentina.
authors: Eliana
authors: E
authors: Marzol
authors: Instituto de Fisiología, Biología Molecular y Neurociencias (IFIBYNE-CONICET), Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Buenos Aires C1428EGA, Argentina.
authors: Juan D
authors: JD
authors: Salgado Salter
authors: Instituto de Fisiología, Biología Molecular y Neurociencias (IFIBYNE-CONICET), Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Buenos Aires C1428EGA, Argentina.
authors: Javier Gloazzo
authors: JG
authors: Dorosz
authors: Instituto de Fisiología, Biología Molecular y Neurociencias (IFIBYNE-CONICET), Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Buenos Aires C1428EGA, Argentina.
authors: Cecilia
authors: C
authors: Borassi
authors: VKR Research Centre, Department of Plant and Environmental Sciences, University of Copenhagen, DK-1871 Frederiksberg C, Denmark.
authors: Svenning Rune
authors: SR
authors: Möller
authors: Department of Botany, University of Wisconsin, Madison, WI 53706, USA.
authors: Rafael
authors: R
authors: Buono
authors: RIKEN Plant Science Center, Tsurumi-ku, Yokohama 230-0045, Japan.
authors: Yukiko
authors: Y
authors: Ohsawa
authors: Laboratory of Plant Nutrition, Faculty of Agriculture, Kyushu University, Hakozaki 6-10-1, Higashi-ku, Fukuoka 812-8581, Japan.
authors: Ken
authors: K
authors: Matsuoka
authors: Department of Botany, University of Wisconsin, Madison, WI 53706, USA.
authors: Marisa S
authors: MS
authors: Otegui
authors: Joint BioEnergy Institute, Feedstocks Division, Lawrence Berkeley National Laboratory, 5885 Hollis Street, Emeryville, CA 94608, USA.
authors: Henrik V
authors: HV
authors: Scheller
authors: VKR Research Centre, Department of Plant and Environmental Sciences, University of Copenhagen, DK-1871 Frederiksberg C, Denmark.
authors: Naomi
authors: N
authors: Geshi
authors: VKR Research Centre, Department of Plant and Environmental Sciences, University of Copenhagen, DK-1871 Frederiksberg C, Denmark.
authors: Bent Larsen
authors: BL
authors: Petersen
authors: Instituto de Fisiología, Biología Molecular y Neurociencias (IFIBYNE-CONICET), Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Buenos Aires C1428EGA, Argentina; Departamento de Fisiología, Biología Molecular y Celular, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Buenos Aires C1428EGA, Argentina.
authors: Norberto D
authors: ND
authors: Iusem
authors: Instituto de Fisiología, Biología Molecular y Neurociencias (IFIBYNE-CONICET), Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Buenos Aires C1428EGA, Argentina. Electronic address: jestevez@fbmc.fcen.uba.ar.
authors: José M
authors: JM
authors: Estevez
mesh_terms: D017360:Arabidopsis / Q000201:enzymology* / Q000235:genetics / Q000254:growth & development; D029681:Arabidopsis Proteins / Q000235:genetics* / Q000378:metabolism*; D015971:Gene Expression Regulation, Enzymologic; D018506:Gene Expression Regulation, Plant; D006031:Glycosylation; D006900:Hydroxylation; D006909:Hydroxyproline / Q000378:metabolism; D005810:Multigene Family; D018517:Plant Roots / Q000201:enzymology / Q000235:genetics / Q000254:growth & development*; D064828:Prolyl Hydroxylases / Q000235:genetics / Q000378:metabolism*
chemical_list: D029681:Arabidopsis Proteins; D064828:Prolyl Hydroxylases; D006909:Hydroxyproline
keywords: cell expansion; cell walls; enzymology; proline hydroxylation; protein targeting; root hairs