Efficient generation of homozygous substitutions in rice in one generation utilizing an rABE8e base editor

Abstract

A new deaminase, TadA8e, was recently evolved in the laboratory. TadA8e catalyzes DNA deamination over 1,000 times faster than ABE7.10. We developed a high-efficiency adenine base editor, rABE8e (rice ABE8e), combining monomeric TadA8e, bis-bpNLS and codon optimization. rABE8e had substantially increased editing efficiencies at NG-protospacer adjacent motif (PAM) and NGG-PAM target sequences compared with ABEmax. For most targets, rABE8e exhibited nearly 100% editing efficiency and high homozygous substitution rates in the specific editing window, especially at Positions A5 and A6. The ability to rapidly generate plant materials with homozygous base substitutions will benefit gene function research and precision molecular breeding.

Keywords: CRISPR; base editing; rABE8e; rice.