Marker-assisted gene introgression for resistance to Xanthomonas oryzae pv. oryzae in rice for the control of bacterial leaf blight

Bacterial leaf blight, sometimes known as BLB, is one of the most damaging diseases that may jeopardize the world’s supply of rice. It is caused by the bacterium Xanthomonas oryzae pv. oryzae (Xoo). It has caused sharp decline in production in regions of the globe that produce rice. More than 40 previously characterized resistance (R) genes enable host tolerance for diverse Xoo strains. In this study, three BLB resistant genes, including xa5, xa13, and Xa21, which have been crucial in disease prevention in Bangladesh, were introgressed into populations. These populations were created by crossing IRRI 154, a popular rice variety with a modern genetic background, with IRBB66 (resistant to BLB). Fifteen virulent bacterial isolates were used for BLB infection, and promising recombinants from the F₅ and BC₂F₄ generations were found to be resistant. Using marker assisted selection (MAS) with gene-specific primers on generations F₅ and BC₂F₄, we were able to find that 60 recombinant introgressed lines (RILs) had a pyramiding of BLB resistance genes. In terms of agronomic performance, the RILs outperformed both their donor and recipient parents, demonstrating that the RILs had pyramided three resistance genes, therefore conferring broad-spectrum BLB resistance. The produced BLB-resistant RILs offer substantial future development potential, either as cultivable crops or as BLB resistance donor material for use in boosting the yields of other rice lines.