Figure 4.

A modified form of a figure from [107,108], which shows the novel GETs without producing the DSBs; (base editing (a), epigenetic modification (b), and prime editing (c)). In (a), by using the base editing approach, two genes (TaALS and TaACCase) are co-edited. This approach is used by coupling the dCas9 with a cytosine base editor (CBE). In this way, such types of transgenic wheat plants are developed, which did not produce any DSBs. (b) is epigenetic editing; in this approach, dCas9-Suntag-hTET1cd is coupled with dCas9 for demethylation of the FWA promoter to activate the FWA gene expression. (c) is prime editing that works by developing a complex interaction between pegRNA, Cas9 nickase-reverse transcriptase (RT), and target DNA. In the pegRNA, except for the primer binding site (PBS), the desired genome sequence is also present, which is introduced in the host genome. For RT, pegRNA produces primer; RT copies the information of pegRNA, and the RT product is integrated with the target genomic site. Initially, modification happens only at one targeted DNA strand. Later, modification is present on both strands due to the cell’s repairing mechanism.