Journal of Genomes and Exomes

Rice blast is a continuous threat in rice ecosystems across the globe; its dynamics is becoming complex in the changing climatic conditions. Host resistance is still a viable option; hence, the exploration of resistance genes and their novel alleles is indispensable. The majority of the blast resistance genes belong to nucleotide-binding site and leucine-rich repeat (LRR) domain. In the present study, diverse LRR alleles of five major blast resistance genes (Pi2, Pi9, Pib, Pita, and Pi37) were cloned from 13 different Oryza species to determine the nucleotide diversity as well as to identify the single nucleotide polymorphisms, InDels, conserved domains, and protein functional sites. Although Pi9 and Pi2 are homologous genes, significant nucleotide variations and variants in the motifs distribution were observed. Among the five genes, Pi37 showed the highest nucleotide diversity and Pita showed the least diversity. The phylogenetic groups of alleles were correlated with the identified haplotypes. The motif (xxLxLxx) was present among all the alleles of blast R gene sequences across various Oryza species, indicating its importance. The appearance of post-translational modification sites in the protein sequences of these alleles also indicates its nature of involvement in host–pathogen interactions. The present study offers clues in further understanding the molecular evolution of the LRR domain of resistance genes, which is a key determinant of host–pathogen interactions.