Direct Interaction of Resistance Gene and Avirulence Gene Products Confers Rice Blast Resistance

EMBO J. 2000 Aug 1;19(15):4004-14. doi: 10.1093/emboj/19.15.4004.

Abstract

Rice expressing the Pi-ta gene is resistant to strains of the rice blast fungus, Magnaporthe grisea, expressing AVR-Pita in a gene-for-gene relationship. Pi-ta encodes a putative cytoplasmic receptor with a centrally localized nucleotide-binding site and leucine-rich domain (LRD) at the C-terminus. AVR-Pita is predicted to encode a metalloprotease with an N-terminal secretory signal and pro-protein sequences. AVR-Pita(176) lacks the secretory and pro-protein sequences. We report here that transient expression of AVR-Pita(176) inside plant cells results in a Pi-ta-dependent resistance response. AVR-Pita(176) protein is shown to bind specifically to the LRD of the Pi-ta protein, both in the yeast two-hybrid system and in an in vitro binding assay. Single amino acid substitutions in the Pi-ta LRD or in the AVR-Pita(176) protease motif that result in loss of resistance in the plant also disrupt the physical interaction, both in yeast and in vitro. These data suggest that the AVR-Pita(176) protein binds directly to the Pi-ta LRD region inside the plant cell to initiate a Pi-ta-mediated defense response.

MeSH terms

  • Binding Sites
  • Biolistics
  • Gene Transfer Techniques
  • Genes, Fungal*
  • Genes, Plant*
  • Magnaporthe / genetics*
  • Magnaporthe / pathogenicity
  • Metalloendopeptidases / genetics
  • Metalloendopeptidases / metabolism
  • Oryza / genetics*
  • Plant Diseases / genetics*
  • Plant Leaves / microbiology
  • Plant Proteins*
  • Protein Binding
  • Receptors, Cytoplasmic and Nuclear / genetics
  • Receptors, Cytoplasmic and Nuclear / metabolism
  • Two-Hybrid System Techniques

Substances

  • Pi-ta protein, Oryza sativa
  • Plant Proteins
  • Receptors, Cytoplasmic and Nuclear
  • AVP-Pita protein, Oryza sativa
  • Metalloendopeptidases