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Dear Editor,Targeted genome editing in plants will not only facilitate functional genomics studies but also help to discover,expand,and create novel traits of agricultural importance (Pennisi,2010).The most widely used approach for editing plant genomes involves generating targeted double-strand DNA breaks (DSBs)and haessing the two main DSB repair pathways:imprecise non-homologous end joining and precise homology-directed repair (Voytas,2013).Enzymes that specifically bind the userselected genomic sequences to create DSBs can be generated de novo as synthetic bimodular proteins containing a DNA-binding module,engineered to bind a user-defined sequence,along with a DNA-cleaving module,capable of making DSBs.Several classes of nucleases have been developed with DNA-binding domains engineered to confer sequence specificity,including homing endonucleases,zinc finger nucleases (ZFNs),and transcription activator-like effector nucleases (TALENs).Customization of these genome editing platforms,however,requires protein engineering,a time-consuming and laborintensive process (Puchta and Fauser,2014).Furthermore,delivery of genome engineering reagents into plant cells is a major barrier to the effective use of these technologies for creating novel traits (Baltes et al.,2014).