Strategies for Characterizing and Cloning Host Specificity Genes in Magnaporthe grisea, the Rice Blast Fungus

Abstract

Although field isolates of the heterothallic Ascomycete, Magnaporthe grisea Barr (anamorph, Pyricularia oryzae Cav. or P. grisea), include pathogens of many grasses, individual isolates have a limited host range, parasitizing one or a few grass species (Mackill et al., 1986). Strains of the fungus that parasitize rice (Oryza sativa) are subdivided into races, depending on the rice cultivars they can successfully infect. The rice blast fungus shows a high degree of variability in the field; new races frequently appear with the ability to attack previously resistant rice cultivars (Ou, 1985).