|Wang, Xueyan - University Of Arkansas|
|Wamishe, Yeshi - University Of Arkansas|
Submitted to: American Phytopathological Society
Publication Type: Abstract Only
Publication Acceptance Date: 5/15/2015
Publication Date: 8/1/2015
Citation: Wang, X., Bianco, T.A., Lin, M.J., Wamishe, Y., Jia, Y. 2015. Quick survey of avirulence genes in field isolates of Magnaporthe oryzae in the past 60 years. APS annual meeting, Pasadena, California, August 1-5, 2015. American Phytopathological Society. p. 312.
Technical Abstract: Avirulence (AVR) genes in Magnaporthe oryzae determine deployment of effective corresponding resistance (R) genes. Instability of AVR genes is the major cause for resistance breakdown. Information on the presence or absence (P/A) of AVR genes can be used as a predictor of the stability of deployed R genes in different rice growing regions. The P/A of AVR genes, AVR-Pi9, AVR-Pita1, AVR-Pik, AVR -Pizt, and ACE1 (AVR-Pi33), in 1000 field isolates collected from the southern USA were examined using AVR gene specific PCR primers. M. oryzae isolates stored on desiccated filter papers were used directly for PCR amplification. This survey revealed 74%, 65%, 82%, 20%, and 76% of the tested isolates carrying AVR-Pi9, AVR-Pita1, AVR-Pizt, AVR-Pik, and AVR-Pi33, respectively. The results indicated that R genes, Pi-9, Pi-ta, Pi-k, Pi-zt, and Pi33, are still effective in preventing rice blast disease in the USA. However, the effectiveness of the resistance can vary by variety grown, location and season. The underlying mechanisms of AVR gene instability are being investigated and results will be reported.