A miniature alternative to Cas9 and Cas12: Transposon-associated TnpB mediates targeted genome editing in plants

Identifying and engineering RNA-guided genome editing nucleases for size reduction is a highly coveted pursuit aimed at overcoming various bottlenecks. The size reduction not only facilitates effective delivery but also contributes to the generation of fusion proteins, enabling versatile applications in genome engineering. In this study, we demonstrate high-efficiency genome editing in both monocots and dicots, with average editing rates ranging from 0.63% to 33.58% and reaching up to 69%, using a 408-amino acid-long transposon-associated TnpB. Furthermore, we repurpose a catalytically dead TnpB system for transcriptional activation and base editing. This miniature TnpB, approximately one-third the size of canonical Cas9/Cas12a, emerges as a highly valuable tool for diverse applications in plant genome engineering and gene regulation.