Submitted to: Experiment Station Bulletins
Publication Type: Experiment station
Publication Acceptance Date: 8/12/2009
Publication Date: N/A
Citation: Interpretive Summary:
Technical Abstract: The resistance gene Pi-ta in rice has been effectively deployed around the globe to prevent the rice blast disease. It was previously known that Pi-ta interacts with the avirulence gene AVR-Pita1 in the fungus in triggering effective resistance responses. In order to predict the stability of deployed Pi-ta in commercial rice cultivars a population of 250 field fungal isolates were collected from major rice production areas worldwide to study the structural and functional properties of AVR-Pita1. Nucleotide variation at AVR-Pita1 was observed in avirulent isolates toward Pi-ta. Structure changes including frame-shift and partial and complete deletions were identified to be new mechanisms for “defeating” the Pi-ta resistance gene. The AVR-Pita1 gene was shown to restore Pi-ta-mediated resistance once it was introduced into three virulent US isolates. These findings suggest that the structural alteration of AVR-Pita1 may impact its roles in resistance and pathogenicity.