A population genetics-based approach reveals candidate gene regions important in the determination of resistance specificity for the Pik family of rice blast resistance genes

Allelic resistance (R) genes at the Pik locus for rice blast resistance consist of two genes, designated as the first gene and the second gene, which each have a nucleotide-binding site and a leucine-rich repeat. We investigated allelic nucleotide sequence diversity at this locus in 36 rice lines and searched for gene regions showing high rates of nonsynonymous nucleotide substitutions. We detected such regions within and near the coiled-coil domain of the first gene but detected only a few nucleotide substitutions in the second gene, suggesting the importance of the N-terminal part of the first protein in the determination of R specificity.