Genetic dissection and identification of blast resistance genes in an elite broad-spectrum resistance rice variety Xiushui114

Rice blast, caused by Magnaporthe oryzae ( M . oryzae ), is one of the most destructive diseases of rice and poses a critical threat to global food security. Breeding rice varieties with broad-spectrum and durable resistance through the deployment of resistance ( R ) genes remains the most effective and economical control strategy. In this study, we identified a highly blast-resistant rice variety, Xiushui114 (XS), by screening diverse rice accessions across three blast nurseries from 2016 to 2019. Pathogenicity assays demonstrated that XS exhibits resistance to more than 16 M. oryzae strains collected from major rice-growing regions, indicating a broad-spectrum resistance phenotype. Genetic analyses revealed that XS carries multiple R genes. Using a map-based cloning approach and sequence analysis further confirmed the presence of several known blast R genes, including Pizh , Pik-KA , Pita , and Pib , in XS. Resistance-spectrum evaluation indicated that Pizh contributes predominantly to the strong resistance observed in XS. Together, these findings establish XS as a valuable germplasm resource for improving rice blast resistance and provide new insights for breeding programs aiming to develop durable, broad-spectrum blast-resistant cultivars. 1. XiuShui114 exhibits high and stable resistance to diverse Magnaporthe oryzae isolates. 2. Major resistance gene Pixs1 was fine-mapped and shown to be allelic to Pizh. 3. Functional assays reveal Pixs1 as the dominant contributor to resistance. 4. Multi-gene combinations in XiuShui114 demonstrate strong complementary effects for durable blast resistance.