Xanthomonas type III effector XopD targets SUMO-conjugated proteins in planta

Mol Microbiol. 2003 Oct;50(2):377-89. doi: 10.1046/j.1365-2958.2003.03730.x.


Xanthomonas campestris pathovar vesicatoria (Xcv) uses the type III secretion system (TTSS) to inject effector proteins into cells of Solanaceous plants during pathogenesis. A number of Xcv TTSS effectors have been identified; however, their function in planta remains elusive. Here, we provide direct evidence for a functional role for a phytopathogenic bacterial TTSS effector in planta by demonstrating that the Xcv effector XopD encodes an active cysteine protease with plant-specific SUMO substrate specificity. XopD is injected into plant cells by the TTSS during Xcv pathogenesis, translocated to subnuclear foci and hydrolyses SUMO-conjugated proteins in vivo. Our studies suggest that XopD mimics endogenous plant SUMO isopeptidases to interfere with the regulation of host proteins during Xcv infection.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Bacterial Proteins / metabolism*
  • Biological Transport, Active
  • Cysteine Endopeptidases / metabolism*
  • Plants / microbiology*
  • Protein Transport / physiology
  • Recombinant Proteins / pharmacology
  • SUMO-1 Protein / metabolism*
  • Xanthomonas campestris / enzymology*
  • Xanthomonas campestris / metabolism


  • Bacterial Proteins
  • Recombinant Proteins
  • SUMO-1 Protein
  • Cysteine Endopeptidases