Precise editing of methylated cytosine in Arabidopsis thaliana using a human APOBEC3Bctd-Cas9 fusion

Dear Editor, Precise editing of specific genomic sites holds great promise in basic research and modern crop breeding,and some cy-tosine base editors (CBEs) have been developed for this purpose (Komor et al.,2016;Zong et al.,2018).Cytosine methylation of DNA plays important roles in regulation of chromatin structure and gene expression in animals,plants and fungi (Law and Jacobsen,2010),and it is known that methylation strongly suppresses cytosine deamination cata-lyzed by some APOBEC and AID deaminases in human cells(Nabel et al.,2012).