A gene-for-gene relationship underlying the species-specific parasitism of Avena/Triticum isolates of Magnaporthe grisea on wheat cultivars

• Published in: Phytopathology Vol. 92; no. 11; pp. 1182 - 1188
• Main Authors: TAKABAYASHI, N, TOSA, Y, OH, H. S, MAYAMA, S
• Format: Journal Article
• Language: English
• Published: St. Paul, MN American Phytopathological Society 01-11-2002
• Subjects: Agronomy. Soil science and plant productions; Biological and medical sciences; Cultivars; Fundamental and applied biological sciences. Psychology; Fungal plant pathogens; Genetics and breeding of economic plants; Parasitism; Pest resistance; Phytopathology. Animal pests. Plant and forest protection; Plant pathogens; Variation, races, biotypes, parasitic specialization, genetics; Varietal selection. Specialized plant breeding, plant breeding aims; Monocotyledones; Temperature; Plant pathogen; Avena; Species specificity; Fungi; Resistance; Sensitivity; Magnaporthe grisea; Gene; Gramineae; Angiospermae; Isolate; Ascomycetes; Spermatophyta; Triticum aestivum; Thallophyta
• ISSN: 0031-949X; 1943-7684
• DOI: 10.1094/phyto.2002.92.11.1182

ABSTRACT To elucidate genetic mechanisms of the species-specific parasitism of Magnaporthe grisea, a Triticum isolate (pathogenic on wheat) was crossed with an Avena isolate (pathogenic on oat), and resulting F(1) progeny were subjected to segregation analyses on wheat cvs. Norin 4 and Chinese Spring. We found two fungal loci, Pwt3 and Pwt4, which are involved in the specific parasitism on wheat. Pwt3 operated on both cultivars while Pwt4 operated only on 'Norin 4'. Using the cultivar specificity of Pwt4, its corresponding resistance gene was successfully identified in 'Norin 4' and designated as Rmg1 (Rwt4). The presence of the corresponding resistance gene indicated that Pwt4 is an avirulence locus. Pwt3 was assumed to be an avirulence locus because of its temperature sensitivity. We suggest that gene-for-gene interactions underlie the species-specific parasitism of M. grisea.