CRISPR-Cas9 can be used to produce two types of gene edits, namely NHEJ and HDR repairs. The NHEJ repair is done by allowing the natural repairing system of the cells inside the plant to create new combinations or mutations in the DNA sequence, whereas HDR is done by providing a template DNA sequence to the cell so that this template would replace the original one. Comparing the two, HDR is relatively more difficult to produce. Nevertheless, researchers from Israel present a method for gene targeting and HDR in tomato.

Tal Dahan-Meir of Weizmann Institute of Science in Israel and colleagues use the replicon to serve as the template-provider for the gene-editing system. Genes CRTISO and PSY1 were precisely modified in tomato using CRISPR-Cas9 system, together with the "bean yellow dwarf virus rolling circle" replicon at 90 percent targeting efficiency. The researchers mentioned the utility of this method in other tomato genes and other crops.

For more information, read the article in The Plant Journal.