Engineering Bacterial Blight Resistance in Rice by PE-Mediated Insertion of Multiple EBEs into the Xa23 Promoter

Bacterial blight caused by Xanthomonas oryzae pv. oryzae (Xoo) is the most serious bacterial disease that seriously reduces the yield of rice. Previous studies showed that insertion of effector binding elements (EBEs) into the Xa23 promoter can confer resistance to various Xanthomonas oryzae pv. oryzae in O. sativa japonica, a model cultivar for research purposes. Therefore, it is necessary to edit elite varieties to test whether this strategy works in rice production. In this research, the grand prime gene editing (PE) method was used to efficiently knock in four consecutive EBE sequences in the promoter region of the resistance gene Xa23 of the elite variety Suijing18. A PE vector was constructed and transformed into rice calli, and transgene-free homozygously edited plants were identified. Bioassay results show that the edited plants exhibited a significantly higher level of resistance to two strains of Xoo, PXO86 and PXO99A, than the wild-type control. This study demonstrated that Grand PE could efficiently introduce resistance to bacterial blight in elite varieties.