ARS | Publication request: Molecular mechanisms of the instability of rice blast fungus avirulence gene AVR-Pita

Submitted to: American Phytopathological Society
Publication Type: Proceedings
Publication Acceptance Date: April 15, 2007
Publication Date: July 29, 2007
Citation: Dai, Y., Jia, Y., Correll, J. 2007. Molecular mechanisms of the instability of rice blast fungus avirulence gene AVR-Pita. American Phytopathological Society, July 28-August 1, 2007, San Diego, CA. 97:S25.

Technical Abstract: AVR-Pita in races of Magnaporthe oryzae (formerly Magnaporthe grisea) is responsible for triggering a strong response by the resistant gene Pi-ta in rice. Pi-ta is a valuable resistance gene that has been deployed to prevent blast disease worldwide. The AVR-Pita gene is located in the telomeric region of chromosome 3 in some races of M. oryzae and encodes a putative neutral zinc metalloprotease. AVR-Pita is predicted to elicit the Pi-ta gene-mediated resistance inside the plant cell. The DNA sequences of natural haplotypes of the AVR-Pita allele have been analyzed. Avirulent isolates collected from different geographic regions of US rice production were observed to have similar AVR-Pita haplotypes with minor amino acid alterations. However, DNA sequence variation has rarely been detected in the intron regions of the AVR-Pita gene. To understand the evolution of the AVR-Pita allele, further sequence analysis is being performed using large collections of M. oryzae isolates worldwide. Resulting knowledge will be useful for predicting the stability of resistance mediated by Pi-ta.