The isolation of Pi1, an allele at the Pik locus which confers broad spectrum resistance to rice blast.

We report the isolation of Pi1, a gene conferring broad-spectrum resistance to rice blast (Magnaporthe oryzae). Using loss- and gain-of-function approaches, we demonstrate that Pi1 is an allele at the Pik locus. Like other alleles at this locus, Pi1 consists of two genes. A functional nucleotide polymorphism (FNP) was identified that allows differentiation of Pi1 from other Pik alleles and other non-Pik genes. A extensive germplasm survey using this FNP reveals that Pi1 is a rare allele in germplasm collections and one that has conferred durable resistance to a broad spectrum of pathogen isolates.