Characterization of Substitution Mutations of eIF4G Gene Generated through Adenine Base Editors in Rice

Adenine base editor (ABE) creates A to G transitions within its editing window. In the present study, an ABE was used to target a stretch of six amino acid residues, VLFPNL in translation initiation factor four gamma (eIF4G) gene of rice. Agrobacterium-mediated transformation of rice cultivar ASD16 resulted in T0 events with high mutation efficiency of 89.29 %. Substitution mutations of A > G occurred within the editing window of four to eight bases at A7 > G7 (74.67 %) and A4 > G4 (2.46 %). Non-canonical substitutions of G > C/A was also observed at G15 > C15 (9.29 %) and G8 > A8 (1.15 %). A total of 15 missense base substitution events affecting the target residue was identified. Taken together, the present study showed that ABEs create unexpected base substitutions besides efficient canonical editing of A > G in the rice genome