ARS | Publication request: Co-evolution of the rice blast resistance gene Pi-ta and Magnaporthe oryzae avirulence gene AVR-Pita1

Submitted to: Phytopathology
Publication Type: Abstract Only
Publication Acceptance Date: March 28, 2010
Publication Date: March 31, 2010
Citation: Jia, Y. 2010. Co-evolution of the rice blast resistance gene Pi-ta and Magnaporthe oryzae avirulence gene AVR-Pita1. In: 19th International Plant Resistance to Insects, Charleston, SC, March 28-31,2010.

Technical Abstract: The Pi-ta gene in rice provides resistance to races of Magnaporthe oryzae that contain the corresponding avirulence gene AVR-Pita1. Pi-ta encodes a predicted receptor protein with nucleotide binding site and leucine rich repeat domain (NBS-LRR) that directly recognizes the products of AVR-Pita1 inside plant cells triggering resistance responses. AVR-Pita1 encodes a predicted metalloprotease that may be involved in pathogen pathogenicity and fitness. Surveys thus far have only identified one resistant Pi-ta protein in diverse rice germplasm collections. Moreover, an intact transposon was identified within the Pi-ta promoter region in resistant rice accessions. Such a transposon was not found in susceptible rice germplasm accessions. Expression analysis using semi-quantitative RT-PCR show that Pi-ta can produce a total of 12 proteins, most of which contain NBS-LRR domains. In contrast, 27 AVR-Pita1 proteins with minor amino acid alterations were identified from avirulent field isolates. Deletion, point and frameshift mutations, and transposon insertions were predicted in virulent avr-pita1 proteins. These findings suggest Pi-ta engages in trench warfare with AVR-Pita1.