Identification of Major QTLs Conferring Rice Blast Resistance Using an SNDH Population

초록

The rice blast pathogen, Magnaporthe oryzae, remains a significant threat to global rice production, often causing substantial yield losses in regions with favorable environmental conditions. Given the limitations of chemical control and the rapid evolution of pathogen populations, developing rice varieties with durable and broad-spectrum blast resistance is crucial for long-term disease management and reducing the overall impact on rice cultivation. To address this need, a qualitative trait locus (QTL) analysis was performed using a set of representative Korean isolates and a ‘Samgang/Nagdong’ doubled haploid (SNDH) population to identify key loci associated with rice blast resistance. Two major and significant loci, qrbr2 (chromosome 2; RM318 –s2038) and qrbr6 (chromosome 6; s6015–s6018), were detected with LOD values of 4.13 and 5.15, accounting for 44% and 43% of the phenotypic variation, respectively. Among the candidate genes within these regions, Os02g0674700 (Osrbrq2), which shares a strong homology with RING-type E3 ubiquitin protein ligases, has emerged as a promising gene that contributes to resistance within the qrbr2 locus. These findings underscore the importance of qrbr2 and qrbr6, along with the Osrbrq2 candidate gene, in shaping rice defense responses, and provide a valuable basis for further characterization and marker-assisted breeding to enhance rice blast resistance.

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