Planta

, Volume 209, Issue 4, pp 424–434

Changes in onion root development induced by the inhibition of peptidyl-prolyl hydroxylase and influence of the ascorbate system on cell division and elongation

Authors

  • Mario C. De Tullio
    • Istituto Botanico, Università di Bari, via E. Orabona 4, I-70125 Bari, Italia
  • Costantino Paciolla
    • Istituto Botanico, Università di Bari, via E. Orabona 4, I-70125 Bari, Italia
  • Francesca Dalla Vecchia
    • Dipartimento di Biologia, Università di Padova, via G. Colombo 3, I-35121 Padova, Italia
  • Nicoletta Rascio
    • Dipartimento di Biologia, Università di Padova, via G. Colombo 3, I-35121 Padova, Italia
  • Saverio D'Emerico
    • Istituto Botanico, Università di Bari, via E. Orabona 4, I-70125 Bari, Italia
  • Laura De Gara
    • Istituto Botanico, Università di Bari, via E. Orabona 4, I-70125 Bari, Italia
  • Rosalia Liso
    • Istituto Botanico, Università di Bari, via E. Orabona 4, I-70125 Bari, Italia
  • Oreste Arrigoni
    • Istituto Botanico, Università di Bari, via E. Orabona 4, I-70125 Bari, Italia
Article

DOI: 10.1007/s004250050745

Cite this article as:
De Tullio, M., Paciolla, C., Dalla Vecchia, F. et al. Planta (1999) 209: 424. doi:10.1007/s004250050745

Abstract.

Post-translational hydroxylation of peptide-bound proline residues, catalyzed by peptidyl-prolyl-4 hydroxylase (EC 1.14.11.2) using ascorbate as co-substrate, is a key event in the maturation of a number of cell wall-associated hydroxyproline-rich glycoproteins (HRGPs), including extensins and arabinogalactan-proteins, which are involved in the processes of wall stiffening, signalling and cell proliferation. Allium cepa L. roots treated with 3,4-DL-dehydroproline (DP), a specific inhibitor of peptidyl-prolyl hydroxylase, showed a 56% decrease in the hydroxyproline content of HRGP. Administration of DP strongly affected the organization of specialized zones of root development, with a marked reduction of the post-mitotic isodiametric growth zone, early extension of cells leaving the meristematic zone and a huge increase in cell size. Electron-microscopy analysis showed dramatic alterations both to the organization of newly formed cell walls and to the adhesion of the plasma membranes to the cell walls. Moreover, DP administration inhibited cell cycle progression. Root tips grown in the presence of DP also showed an increase both in ascorbate content (+53%) and ascorbate-specific peroxidase activity in the cytosol (+72%), and a decrease in extracellular “secretory” peroxidase activity (−73%). The possible interaction between HRGPs and the ascorbate system in the regulation of both cell division and extension is discussed.

Key words:Allium (root development)AscorbateCell divisionCell expansionHydroxyproline-containing proteinRoot development

Copyright information

© Springer-Verlag Berlin Heidelberg 1999