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Identification of Magnaporthe oryzae Avirulence Genes to Three Rice Blast Resistance Genes

March 2004 , Volume 88 , Number  3
Pages  265 - 270

C. X. Luo , Faculty of Agriculture, Saga University, Saga, 840-8502, Japan ; Y. Fujita , National Agricultural Research Center for Hokkaido Region, Sapporo, 062-8555, Japan ; N. Yasuda , National Agricultural Research Center, Tsukuba, 305-8666, Japan ; K. Hirayae , National Agricultural Research Center, Joetsu, 943-0193, Japan ; T. Nakajima , National Agricultural Research Center for Kyushu Okinawa Region, Kumamoto, 861-1192, Japan ; N. Hayashi , National Institute of Agrobiological Sciences, Tsukuba, 305-8602, Japan ; and M. Kusaba and H. Yaegashi , Faculty of Agriculture, Saga University, Saga, 840-8502, Japan

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Accepted for publication 9 October 2003.

The segregation of avirulence/virulence was studied in 115 F1 progeny isolates of Magnaporthe oryzae from a cross of two field isolates on three Japanese race-differential rice cultivars Kanto 51, Fukunishiki, and Toride 1. The χ2 tests of goodness-of-fit for a 1:1 ratio indicated that avirulence on cvs. Kanto 51, Fukunishiki, and Toride 1 was under monogenic control. The relationship between the avirulence (Avr) gene in the parental isolate and the Avr gene in the standard isolate was investigated by using 100 lines each of three F3 families from the crosses of the rice cultivars Norin 3/Kanto 51, AK61/Fukunishiki, and Norin 3/Toride 1, respectively. Based on the resistant reactions of the F3 rice lines to the parental isolates and the standard isolates harboring three known Avr genes, three genetically independent Avr genes, AvrPik, AvrPiz, and AvrPiz-t, were identified. The three identified Avr genes were mapped using random amplified polymorphic DNA (RAPD) analysis, and a partial linkage map was constructed with 17 RAPD markers closely linked to the Avr genes. Twelve markers and AvrPik, three markers and AvrPiz, and two markers and AvrPiz-t, as well as mating locus MAT1, constructed linkage groups A, B, and C, respectively.

Additional keywords: Pyricularia oryzae, rice blast fungus

© 2004 The American Phytopathological Society