Submitted to: Plant and Animal Genome Conference
Publication Type: Abstract Only
Publication Acceptance Date: 1/3/2020
Publication Date: 1/10/2020
Citation: Jia, Y., Zhai, H., Jia, M.H., Liu, Y. 2020. Identification of critical amino acid residues in Ptr mediated plant innate immunity [abstract]. Plant and Animal Genome Conference, San Diego, California, January 11-15, 2020.
Technical Abstract: The Ptr gene in cultivated rice varieties confers resistance to a wide range of races of Magnaporthe oryzae, which causes rice blast disease, except for US pathotypes IE-lk and IB33, the latter being one of the most virulent blast races. Ptr was identified approximately 200 kb from the Pi-ta locus encoding, a protein with 4 armadillo repeats. Here we report that an allelic variant of Ptr with minor amino acid variation in a black hull, awned weedy rice strain is responsible for resistance to IB33. One black hull, awned weedy rice x cultivated rice mapping population of 200 individuals was used for mapping with IB33 under greenhouse conditions. The resistance factor to IB33 was mapped at the Ptr locus between single nucleotide polymorphic marker (SNP) 10.633,942bp and 10.820,033 bp with the closest SNP at 10.724,430 bp excluding both Pi-ta and Pi-ta2 (another NLR protein). We then developed a gene specific marker for a portion of the Ptr gene and examined the existence of the Ptr gene in each individual of the mapping population along with their reactions to IB33. The presence of the gene specific marker of Ptr observed in individuals resistant to IB33 suggests that the haplotype of Ptr in black hulled awned weedy rice is responsible for resistance to IB33. This finding helps in the identification of critical amino acid residues of the Ptr protein for detecting the pathogen signal in triggering effective plant innate immunity. Ideas on how to utilize both Pi-ta and Ptr in preventing rice blast disease will be presented.