Identification of a new locus, Ptr(t), required for rice blast resistance gene Pi-ta-mediated resistance

Mol Plant Microbe Interact. 2008 Apr;21(4):396-403. doi: 10.1094/MPMI-21-4-0396.


Resistance to the blast pathogen Magnaporthe oryzae is proposed to be initiated by physical binding of a putative cytoplasmic receptor encoded by a nucleotide binding site-type resistance gene, Pi-ta, to the processed elicitor encoded by the corresponding avirulence gene AVR-Pita. Here, we report the identification of a new locus, Ptr(t), that is required for Pi-ta-mediated signal recognition. A Pi-ta-expressing susceptible mutant was identified using a genetic screen. Putative mutations at Ptr(t) do not alter recognition specificity to another resistance gene, Pi-k(s), in the Pi-ta homozygote, indicating that Ptr(t) is more likely specific to Pi-ta-mediated signal recognition. Genetic crosses of Pi-ta Ptr(t) and Pi-ta ptr(t) homozygotes suggest that Ptr(t) segregates as a single dominant nuclear gene. A ratio of 1:1 (resistant/susceptible) of a population of BC1 of Pi-ta Ptr(t) with pi-ta ptr(t) homozygotes indicates that Pi-ta and Ptr(t) are linked and cosegregate. Genotyping of mutants of pi-ta ptr(t) and Pi-ta Ptr(t) homozygotes using ten simple sequence repeat markers at the Pi-ta region determined that Pi-ta and Ptr(t) are located within a 9-megabase region and are of indica origin. Identification of Ptr(t) is a significant advancement in studying Pi-ta-mediated signal recognition and transduction.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Alleles
  • Genes, Plant / genetics*
  • Genotype
  • Immunity, Innate / genetics
  • Magnaporthe / growth & development*
  • Mutation
  • Oryza / genetics*
  • Oryza / microbiology
  • Plant Diseases / genetics*
  • Plant Diseases / microbiology
  • Sequence Analysis, DNA