Coevolutionary Dynamics of Rice Blast Resistance Gene Pi-ta and Magnaporthe oryzae Avirulence Gene AVR-Pita 1

Phytopathology. 2016 Jul;106(7):676-83. doi: 10.1094/PHYTO-02-16-0057-RVW. Epub 2016 May 13.


The Pi-ta gene in rice is effective in preventing infections by Magnaporthe oryzae strains that contain the corresponding avirulence gene, AVR-Pita1. Diverse haplotypes of AVR-Pita1 have been identified from isolates of M. oryzae from rice production areas in the United States and worldwide. DNA sequencing and mapping studies have revealed that AVR-Pita1 is highly unstable, while expression analysis and quantitative resistance loci mapping of the Pi-ta locus revealed complex evolutionary mechanisms of Pi-ta-mediated resistance. Among these studies, several Pi-ta transcripts were identified, most of which are probably derived from alternative splicing and exon skipping, which could produce functional resistance proteins that support a new concept of coevolution of Pi-ta and AVR-Pita1. User-friendly DNA markers for Pi-ta have been developed to support marker-assisted selection, and development of new rice varieties with the Pi-ta markers. Genome-wide association studies revealed a link between Pi-ta-mediated resistance and yield components suggesting that rice has evolved a complicated defense mechanism against the blast fungus. In this review, we detail the current understanding of Pi-ta allelic variation, its linkage with rice productivity, AVR-Pita allelic variation, and the coevolution of Pi-ta and AVR-Pita in Oryza species and M. oryzae populations, respectively. We also review the genetic and molecular basis of Pi-ta and AVR-Pita interaction, and its value in marker-assisted selection and engineering resistance.

Publication types

  • Review

MeSH terms

  • Biological Evolution*
  • Host-Pathogen Interactions / genetics*
  • Magnaporthe / genetics*
  • Oryza / genetics*
  • Oryza / growth & development
  • Oryza / immunology
  • Plant Immunity / genetics
  • Plant Proteins / genetics*
  • Receptors, Cytoplasmic and Nuclear / genetics*


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