Expanded Base Editing in Rice and Wheat Using a Cas9-adenosine Deaminase Fusion

Chao Li, Yuan Zong, Yanpeng Wang, Shuai Jin, Dingbo Zhang, Qianna Song, Rui Zhang and Caixia Gao

 

Genome Biology

DOI:10.1186/s13059-018-1443-z

 

Abstract

 

Nucleotide base editors in plants have been limited to conversion of cytosine to thymine. Here, we describe a new plant adenine base editor based on an evolved tRNA adenosine deaminase fused to the nickase CRISPR/Cas9, enabling A？T to G？C conversion at frequencies up to 7.5% in protoplasts and 59.1% in regenerated rice and wheat plants. An endogenous gene is also successfully modified through introducing a gain-of-function point mutation to directly produce an herbicide-tolerant rice plant. With this new adenine base editing system, it is now possible to precisely edit all base pairs, thus expanding the toolset for precise editing in plants.