SGT1b is required for HopZ3-mediated suppression of the epiphytic growth of Pseudomonas syringae on N. benthamiana

Plant Signal Behav. 2012 Sep 1;7(9):1129-31. doi: 10.4161/psb.21319. Epub 2012 Aug 17.


Type III secreted effectors shape the potential of bacterial pathogens to cause disease on plants. Some effectors affect pathogen growth only in specific niches. For example, HopZ3 causes reduced epiphytic growth of Pseudomonas syringae strain B728a on Nicotiana benthamiana. This raises the question of whether genes important for effector-triggered disease resistance are needed for responses to effectors whose major effect is in the epiphytic niche. We report that SGT1b, a protein known to be important for defense activation, is essential for HopZ3-mediated suppression of PsyB728a epiphytic growth. SGT1b is required for HopZ3- and AvrB3-induced cell death in N. benthamiana plants that express the Pto resistance gene from tomato. We suggest that HopZ3 activates R gene mediated responses in N. benthamiana.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Bacterial Proteins / metabolism*
  • Cell Death / genetics
  • Disease Resistance / genetics*
  • Genes, Plant*
  • Lycopersicon esculentum / genetics
  • Plant Diseases* / genetics
  • Plant Diseases* / microbiology
  • Plant Leaves / microbiology
  • Plant Proteins / genetics
  • Plant Proteins / metabolism
  • Plants, Genetically Modified
  • Protein Serine-Threonine Kinases / genetics
  • Pseudomonas syringae* / growth & development
  • Pseudomonas syringae* / pathogenicity
  • Tobacco / genetics*
  • Tobacco / metabolism
  • Tobacco / microbiology


  • Bacterial Proteins
  • Plant Proteins
  • Pto protein, Lycopersicon
  • Protein Serine-Threonine Kinases