Controllable Auto-Excision Now Possible with CRISPR-Cas9

A new CRISPR-Cas9-based vector system that can deliver the target gene-of-interest into plants while removing undesired genetic traces was developed in Canada. The new system features controllable auto-excision through its core design of embedded multi-clonal sequence and the use of inducible promoters to control the expression of the Cas9 nuclease.

The embedded multiclonal sequence is what controls the inserted sequences. This feature has three pre-designed CRISPR-Cas9 sites for targeted editing and two types of restriction enzyme sites for each functional component. The mosaic design allows the end-user to have more control of what will happen to each functional component in the end product. This gives breeders the option to choose a restriction site for their identified gene or genes of interest, and it has the potential to make rearrangement of other components through common cloning techniques.

Using the new system, the developers were able to demonstrate that novel cisgenic plant germplasms with the desired traits can be developed in just one or two generations. They also noted that heat treatment at 37°C could significantly improve the editing efficacy and that no off-target mutations were identified.

This novel vector system is the first CRISPR-Cas9-based genome editing tool for cisgenic plant breeding.

Read more about its potentials in the International Journal of Plant Sciences.