Method for base editing in plants

A system for performing base editing to a target sequence in a plant genome, comprising at least one of the following (i) to (v):

• i)a base editing fusion protein, and a guide RNA;
• ii) an expression construct comprising a nucleotide sequence encoding a base editing fusion protein, and a guide RNA;
• iii) a base editing fusion protein, and an expression construct comprising a nucleotide sequence encoding a guide RNA;
• iv) an expression construct comprising a nucleotide sequence encoding a base editing fusion protein, and an expression construct comprising a nucleotide sequence encoding a guide RNA;
• v) an expression construct comprising a nucleotide sequence encoding base editing fusion protein and a nucleotide sequence encoding guide RNA;
• wherein said base editing fusion protein contains a nuclease-inactivated Cas9 domain and a deaminase domain, said guide RNA can target said base editing fusion protein to the target sequence in the plant genome,
• wherein said deaminase domain is fused through a linker to the N-terminal of said nuclease-inactivated Cas9 domain,
• wherein the base editing fusion protein comprises an amino acid sequence as encoded by the nucleotide sequence as set forth in SEQ ID NO:
• 19 or 20,
• wherein the deaminase is an apolipoprotein B mRNA editing complex (APOBEC) family deaminase having a deamination window of 7 nucleotides at positions 3-9 of the protospacer sequence, and
• wherein the nucleotide sequence encoding the base editing fusion protein is codon optimized for plants to be base edited.