Planta

, Volume 236, Issue 5, pp 1419–1431

Deciphering the route of Ralstonia solanacearum colonization in Arabidopsis thaliana roots during a compatible interaction: focus at the plant cell wall

Authors

  • Catherine Digonnet
    • Université de Toulouse, UPS, UMR 5546, Laboratoire de Recherche en Sciences Végétales
    • Centre National de la Recherche Scientifique, CNRSUMR 5546, Laboratoire de Recherche en Sciences Végétales
  • Yves Martinez
    • Centre National de la Recherche Scientifique, CNRSPlateforme Imagerie-Microscopie, Fédération de Recherche FR3450
  • Nicolas Denancé
    • Université de Toulouse, UPS, UMR 5546, Laboratoire de Recherche en Sciences Végétales
    • Centre National de la Recherche Scientifique, CNRSUMR 5546, Laboratoire de Recherche en Sciences Végétales
  • Marine Chasseray
    • Université de Toulouse, UPS, UMR 5546, Laboratoire de Recherche en Sciences Végétales
    • Centre National de la Recherche Scientifique, CNRSUMR 5546, Laboratoire de Recherche en Sciences Végétales
  • Patrick Dabos
    • Institut National de la Recherche Agronomique, INRAUMR 441, Laboratoire des Interactions Plantes Microorganismes
    • Centre National de la Recherche Scientifique, CNRSUMR 2594, Laboratoire des Interactions Plantes Microorganismes
  • Philippe Ranocha
    • Université de Toulouse, UPS, UMR 5546, Laboratoire de Recherche en Sciences Végétales
    • Centre National de la Recherche Scientifique, CNRSUMR 5546, Laboratoire de Recherche en Sciences Végétales
  • Yves Marco
    • Institut National de la Recherche Agronomique, INRAUMR 441, Laboratoire des Interactions Plantes Microorganismes
    • Centre National de la Recherche Scientifique, CNRSUMR 2594, Laboratoire des Interactions Plantes Microorganismes
  • Alain Jauneau
    • Centre National de la Recherche Scientifique, CNRSPlateforme Imagerie-Microscopie, Fédération de Recherche FR3450
    • Université de Toulouse, UPS, UMR 5546, Laboratoire de Recherche en Sciences Végétales
    • Centre National de la Recherche Scientifique, CNRSUMR 5546, Laboratoire de Recherche en Sciences Végétales
Original Article

DOI: 10.1007/s00425-012-1694-y

Cite this article as:
Digonnet, C., Martinez, Y., Denancé, N. et al. Planta (2012) 236: 1419. doi:10.1007/s00425-012-1694-y

Abstract

The compatible interaction between the model plant, Arabidopsis thaliana, and the GMI1000 strain of the phytopathogenic bacterium, Ralstonia solanacearum, was investigated in an in vitro pathosystem. We describe the progression of the bacteria in the root from penetration at the root surface to the xylem vessels and the cell type-specific, cell wall-associated modifications that accompanies bacterial colonization. Within 6 days post inoculation, R. solanacearum provoked a rapid plasmolysis of the epidermal, cortical, and endodermal cells, including those not directly in contact with the bacteria. Plasmolysis was accompanied by a global degradation of pectic homogalacturonanes as shown by the loss of JIM7 and JIM5 antibody signal in the cell wall of these cell types. As indicated by immunolabeling with Rsol-I antibodies that specifically recognize R. solanacearum, the bacteria progresses through the root in a highly directed, centripetal manner to the xylem poles, without extensive multiplication in the intercellular spaces along its path. Entry into the vascular cylinder was facilitated by cell collapse of the two pericycle cells located at the xylem poles. Once the bacteria reached the xylem vessels, they multiplied abundantly and moved from vessel to vessel by digesting the pit membrane between adjacent vessels. The degradation of the secondary walls of xylem vessels was not a prerequisite for vessel colonization as LM10 antibodies strongly labeled xylem cell walls, even at very late stages in disease development. Finally, the capacity of R. solanacearum to specifically degrade certain cell wall components and not others could be correlated with the arsenal of cell wall hydrolytic enzymes identified in the bacterial genome.

Keywords

ArabidopsisCell wallCytologyPlant–pathogen interactionRalstoniaRoot

Abbreviations

dpi

Days post-inoculation

HG

Homogalacturonan

PEL

Pectate lyase

PG

Polygalacturonase

PL

Pectin lyase

PME

Pectin methylesterase

TEM

Transmission electron microscopy

Supplementary material

425_2012_1694_MOESM1_ESM.doc (49 kb)
Supplementary material 1 (DOC 49 kb)
425_2012_1694_MOESM2_ESM.ppt (433 kb)
Supplementary material 2 (PPT 433 kb)

Copyright information

© Springer-Verlag 2012