Engineer and split an efficient hypercompact CRISPR–CasΦ genome editor in plants

Abstract

The programmable CRISPR-Cas genome editing technology, adopted from prokaryotic adaptive immune systems, has revolutionized genome engineering in plants (Liu et al., 2022a). Many efforts have been made to improve the activity, specificity, and protospacer adjacent motif (PAM) variants of Class 2 Cas nucleases, such as Cas9, Cas12a, and Cas12b (Liu et al., 2022a). However, their large size (∼1000–1400 amino acids) poses a challenge in scenarios requiring a compact Cas nuclease, particularly in urgent situations like plant virus-induced genome editing (Cheuk and Houde, 2018; Li et al., 2021; Varanda et al., 2021).