IsDge10 is a hypercompact TnpB nuclease that confers efficient genome editing in rice

Dear Editor,Cas9 and Cas12a have been widely applied in genome engineering in both plant and human cells(Tang and Zhang,2023).However,the relatively large sizes restrict their delivery into cells via viral vectors.As hypothetical ancestors of Cas9 and Cas12a,IscB and TnpB have been reported as RNA-guided DNA endonucleases suitable for genome editing in human cells(Han et al.,2023;Xiang et al.,2023).More recently,a eukaryotic RNA-guided endonuclease named Fanzor has demonstrated genome editing capabilities in human cells(Saito et al.,2023).These nucleases,such as IsDge10,are significantly smaller(∼390 amino acids for IsDge10)compared to Cas9 and Cas12a(e.g.,∼1300 amino acids for SpCas9).However,the applicability of TnpB,IscB,or Fanzor for plant genome engineering remained unexplored.Here,we evaluated a series of nucleases from the TnpB,IscB,and Fanzor families and successfully developed a miniature plant genome editor using IsDge10,a TnpB nuclease from Deinococcus geothermalis.