摘要Exploiting novel endogenous glyphosate-tolerant alleles is highly desirable and has promising potential for weed control in rice breeding.Here,through fusions of different effective cytosine and adenine deaminases with nCas9-NG,we en-gineered an effective surrogate two-component composite base editing system,STCBE-2,with improved C-to-T and A-to-G base editing efficiency and expanded the editing window.Furthermore,we targeted a rice endogenous OsEPSPS gene for artificial evolution through STCBE-2-mediated near-saturated mutagenesis.After hygromycin and glyphosate selection,we identified a novel OsEPSPS allele with an Asp-213-Asn(D213N)mutation(OsEPSPS-D213N)in the predicted glyphosate-binding domain,which conferred rice plants reliable glyphosate tolerance and had not been reported or applied in rice breeding.Collec-tively,we developed a novel dual base editor which will be valuable for artificial evolution of important genes in crops.And the novel glyphosate-tolerant rice germplasm generated in this study will benefit weeds management in rice paddy fields.