Boosting CRISPR/Cas9 multiplex editing capability with the endogenous tRNA-processing system

Significance The clustered regularly interspaced short palindromic repeat (CRISPR)/CRISPR-associated protein 9 nuclease (Cas9) system has recently emerged as an efficient and versatile tool for genome editing in various organisms. However, its targeting capability and multiplex editing efficiency are often limited by the guide RNA (gRNA)-expressing device. This study demonstrates a general strategy and platform for precise processing and efficient production of numerous gRNAs in vivo from a synthetic polycistronic gene via the endogenous tRNA-processing system. This strategy is shown to significantly increase CRISPR/Cas9 multiplex editing capability and efficiency in plants and is expected to have broad applications for small RNA expression and genome engineering.