Page Banner

United States Department of Agriculture

Agricultural Research Service

Research Project: Using Genetic Approaches to Reduce Crop Losses in Rice Due to Biotic and Abiotic Stress

Location: Dale Bumpers National Rice Research Center

Title: Induction of avirulence by AVR-Pita1 in virulent U.S. field isolates of Magnaporthe

Authors
item Dai, Yuntao -
item Winston, Eugenia -
item Correll, James -
item JIA, YULIN

Submitted to: The Crop Journal
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: November 12, 2013
Publication Date: December 12, 2013
Citation: Dai, Y., Winston, E., Correll, J.C., Jia, Y. 2013. Induction of avirulence by AVR-Pita1 in virulent U.S. field isolates of Magnaporthe. The Crop Journal. http://dx.doi.org/10.1016/j.cj.2013.12.002.

Interpretive Summary: The AVR-Pita1 gene of rice blast fungus is an effector that determines the efficacy of the Pi-ta rice blast resistance gene. In the present study, the avirulence function of AVR-Pita1 was induced by transformation of field isolates (TM2, ZN19, B2 and B8) that originally were collected from the U.S. and are virulent on Pi-ta-carrying rice cultivars. The results of pathogenicity assays demonstrated that the AVR-Pita1-transformed isolates were not able to infect US rice cultivars Katy and Drew carrying Pi-ta. Our findings demonstrate that AVR-Pita1 can be used to induce novel gene-specific blast resistance in nature.

Technical Abstract: The AVR-Pita1 gene, from the Chinese isolate O-137 of Magnaporthe oryzae, is an effector that determines the efficacy of the Pi-ta rice blast resistance gene. In the present study, the avirulence function of AVR-Pita1 was induced by transformation of field isolates (TM2, ZN19, B2 and B8) that originally were collected from the U.S. and are virulent on Pi-ta-carrying rice cultivars. The presence of AVR-Pita1 from O-137 in independent transformants was detected by PCR using AVR-Pita1 specific primers and verified by DNA sequencing and Southern blot analysis using the AVR-Pita1 coding region as a probe. The results of pathogenicity assays showed that the AVR-Pita1-transformed isolates were not able to infect rice cultivars Katy and Drew carrying Pi-ta. Control isolates that were transformed with inserts lacking the AVR-Pita1 gene remained virulent. Our findings demonstrate that AVR-Pita1can be used to induce novel gene-specific blast resistance in nature.

Last Modified: 9/10/2014
Footer Content Back to Top of Page