Planta

, Volume 225, Issue 3, pp 541–550

Medicago truncatula syntaxin SYP132 defines the symbiosome membrane and infection droplet membrane in root nodules

  • Christina M. Catalano
  • Kirk J. Czymmek
  • Janine G. Gann
  • D. Janine Sherrier
Original Article

DOI: 10.1007/s00425-006-0369-y

Cite this article as:
Catalano, C.M., Czymmek, K.J., Gann, J.G. et al. Planta (2007) 225: 541. doi:10.1007/s00425-006-0369-y

Abstract

Symbiotic association of legume plants with rhizobia bacteria culminates in organogenesis of nitrogen-fixing root nodules. In indeterminate nodules, plant cells accommodate rhizobial infection by enclosing each bacterium in a membrane-bound, organelle-like compartment called the symbiosome. Numerous symbiosomes occupy each nodule cell; therefore an enormous amount of membrane material must be delivered to the symbiosome membrane for its development and maintenance. Protein delivery to the symbiosome is thought to rely on the plant secretory system; however, the targeting mechanisms are not well understood. In this study, we report the first in-depth analysis of a syntaxin localized on symbiosome membranes. Syntaxins help define a biochemical identity to each compartment in the plant secretory system and facilitate vesicle docking and fusion. Here, we present biochemical and cytological evidence that the SNARE MtSYP132, a Medicago truncatula homologue of Arabidopsis thaliana Syntaxin of Plants 132, localizes to the symbiosome membrane. Using a specific anti-MtSYP132 peptide antibody, we also show that MtSYP132 localizes to the plasma membrane surrounding infection threads and is most abundant on the infection droplet membrane. These results indicate that MtSYP132 may function in infection thread development or growth and the early stages of symbiosome formation.

Keywords

Infection threadMedicagoNoduleSymbiosome membraneSyntaxinSNARE

Abbreviations

ELISA

Enzyme-linked immunosorbent assay

Fmoc

9-Flourenylmethloxycarbonyl

KLH

Keyhole limpet hemocyanin

MtSYP132

Medicago truncatula syntaxin

Pipes

Piperazine-1,4-bis(2-ethanesulfonic acid)

SDS-PAGE

Sodium dodecyl sulfate polyacrylamide gel electrophoresis

SNARE

Soluble N-ethylmaleimide-sensitive factor adaptor protein receptors

TBS

Tris buffered saline

TBST

TBS with Tween-20

Supplementary material

425_2006_369_MOESM1_ESM.pdf (514 kb)
Supplementary material

Copyright information

© Springer-Verlag 2006

Authors and Affiliations

  • Christina M. Catalano
    • 1
    • 2
  • Kirk J. Czymmek
    • 2
    • 3
  • Janine G. Gann
    • 1
    • 2
  • D. Janine Sherrier
    • 1
    • 2
    • 3
  1. 1.Department of Plant and Soil SciencesUniversity of Delaware NewarkUSA
  2. 2.Delaware Biotechnology InstituteUniversity of DelawareNewarkUSA
  3. 3.Department of Biological SciencesUniversity of DelawareNewarkUSA