Magnaporthe oryzae

The filamentous fungus Magnaporthe oryzae (anamorph: Pyricularia oryzae) causes blast, the most devastating disease of cultivated rice. M. oryzae is a haploid ascomycete that grows as branching hyphae and disperses via three-celled, tear-shaped asexual conidiospores produced sympodially on aerial hyphae. Sexual reproduction occurs in the laboratory and is also evident in population studies but has not been observed in the field. M. oryzae has a sequenced genome, can be cultured away from the host, and is readily transformable. This facilitates detailed functional genomic studies involving targeted gene deletion by homologous recombination, genome-wide '-omics' investigations, and the use of fluorescent reporters for live-cell imaging. Recent studies – focused on understanding infection-related development, host invasion, and fungal growth in rice cells – have improved our understanding of rice blast fungus biology and the molecular underpinnings of host infection. Such findings may aid the search for durable disease mitigation strategies. For example, knowledge of the proteins involved in host penetration recently led to the discovery of broad-spectrum fungicides targeting this crucial step.