The rice resistance protein pair RGA4/RGA5 recognizes the Magnaporthe oryzae effectors AVR-Pia and AVR1-CO39 by direct binding

Plant Cell. 2013 Apr;25(4):1463-81. doi: 10.1105/tpc.112.107201. Epub 2013 Apr 2.


Resistance (R) proteins recognize pathogen avirulence (Avr) proteins by direct or indirect binding and are multidomain proteins generally carrying a nucleotide binding (NB) and a leucine-rich repeat (LRR) domain. Two NB-LRR protein-coding genes from rice (Oryza sativa), RGA4 and RGA5, were found to be required for the recognition of the Magnaporthe oryzae effector AVR1-CO39. RGA4 and RGA5 also mediate recognition of the unrelated M. oryzae effector AVR-Pia, indicating that the corresponding R proteins possess dual recognition specificity. For RGA5, two alternative transcripts, RGA5-A and RGA5-B, were identified. Genetic analysis showed that only RGA5-A confers resistance, while RGA5-B is inactive. Yeast two-hybrid, coimmunoprecipitation, and fluorescence resonance energy transfer-fluorescence lifetime imaging experiments revealed direct binding of AVR-Pia and AVR1-CO39 to RGA5-A, providing evidence for the recognition of multiple Avr proteins by direct binding to a single R protein. Direct binding seems to be required for resistance as an inactive AVR-Pia allele did not bind RGA5-A. A small Avr interaction domain with homology to the Avr recognition domain in the rice R protein Pik-1 was identified in the C terminus of RGA5-A. This reveals a mode of Avr protein recognition through direct binding to a novel, non-LRR interaction domain.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Alternative Splicing
  • Amino Acid Sequence
  • Binding Sites / genetics
  • Disease Resistance / genetics
  • Fluorescence Resonance Energy Transfer
  • Fungal Proteins / genetics*
  • Fungal Proteins / metabolism
  • Host-Pathogen Interactions
  • Immunoblotting
  • Magnaporthe / genetics*
  • Magnaporthe / metabolism
  • Magnaporthe / physiology
  • Microscopy, Confocal
  • Molecular Sequence Data
  • Mutation
  • Oryza / genetics*
  • Oryza / metabolism
  • Oryza / microbiology
  • Plant Diseases / genetics
  • Plant Diseases / microbiology
  • Plant Proteins / genetics*
  • Plant Proteins / metabolism
  • Plants, Genetically Modified
  • Protein Binding
  • Protein Isoforms / genetics
  • Protein Isoforms / metabolism
  • Two-Hybrid System Techniques


  • Fungal Proteins
  • Plant Proteins
  • Protein Isoforms