Adenine Base Editor Creates Novel Substitution Mutations in eIF4G Gene of Rice

Two single nucleotide polymorphic mutations and deletion affecting Y1059V1060V1061 amino acid residues in a host translation initiation factor four gamma (eIF4G) gene in rice are reported to confer resistance to rice tungrospherical virus in resistant genotypes. A CRISPR-based adenine base editing vector was used to target these residues in a susceptible indica cultivar, ASD16.Agrobacterium-mediated transformation of ASD16 generated 16 missense mutants and two deletion mutants. Substitution mutations occurred at A5> G5 and A4> G4, where 5.5 % and 3.37 % of adenosines got converted to guanosines, respectively. The mutantsgenerated had missense mutations affecting the YVV residues and the residues immediately adjacent to YVV.Thus,these novel mutationsare promising candidates in imparting resistance against rice tungro disease.