Agrobacterium-mediated Delivery of the CRISPR/Cas9 System in Tomato

Precise genome editing technologies such as the CRISPR-Cas9 system have been used by many researchers to improve crop traits. Several studies using the CRISPR-Cas9 system have proven its efficiency in inducing DNA double-strand breaks (DSBs) in genomes. Researchers from France reported successful transgene-free gene targeting using Agrobacterium-mediated delivery of the CRISPR-Cas9 system in tomato. Their results are published in Plant Cell Reports.

The researchers used a simple system based on a single binary vector expressing Cas9, a single sgRNA, the kanamycin resistance gene and a modified donor DNA template that is not recognized by the sgRNA for gene editing. It was shown that the efficiency of the ALS1 gene editing was high, compared to other studies applying Agrobacterium-mediated transformation. The use of kanamycin allowed transfected cells to express the Cas9 protein and the sgRNA at a level sufficient enough to ensure efficient DSBs formation and to contain at the same time sufficient DNA donor templates to favor homology-directed repair (HDR) of some of these DSBs.

The study was the first reporting of transgene-free HDR-mediated genome editing of tomato using Agrobacterium-CRISPR/Cas9 delivery. The technique used may be applied in the development of better tomato varieties as well as its related species such as potato.

Read more in Plant Cell Reports.