A novel locus from the wild allotetraploid rice, Oryza latiolia Desv. confers bacterial blight (Xanthomonas oryzae pv. oryzae) resistance in rice (O. sativa L.)

Bacterial blight caused by Xanthomonas oryzae pv. oryzae (Xoo) is a major limiting factor to rice productivity worldwide. Genetic control through the identification of novel sources of bacterial blight resistance and their utilization in resistance breeding in rice remains the most effective and economical strategy to manage the disease. Here we report the identification of a novel locus from the wild rice species, Oryza latifolia, conferring a race-specific resistance to Philippine Xoo race 9A (PXO339). The locus was identified from two introgression lines i.e. WH12-2252 and WH12-2256 that segregated from O. latifolia monosomic alien addition lines (MAALs). The discrete segregation ratio of susceptible and resistant phenotypes in the F2 (χ2[3:1] = 0.22 at p>0.05) and F3 (χ2[3:1] = 0.36 at p>0.05) populations indicates that PXO339 resistance in the MAAL-derived introgression lines (MDILs) is controlled by a single, recessive gene. Genotyping of a total of 216 F2, 1130 F3 and 288 F4 pl