Developing herbicide tolerance in common bean through genome editing technology.

Herbicide tolerance is a key trait for crop management. For Phaseolus vulgaris (common bean) the herbicide Pursuit is generally utilized pre-emergence or preplant incorporated to control broadleaf weeds. Although common beans have good tolerance to this herbicide, a major disadvantage is a narrow margin of crop safety which can result in crop injury and reduced yield. Pursuit is part of the imidazolinone or group 2 herbicides which act as inhibitors of acetolactate synthase (ALS). Other crop species with resistance to this herbicide have been developed and marketed in parts of Canada. These cultivars integrate variants of the ALS enzyme incorporating mutations rendering the enzyme insensitive to the imidazolinone inhibitor acting as the herbicide. We have determined the locations of the putative mutation that would be required to induce tolerance to Pursuit in common bean ALS genes. Using our successful regeneration methods, we are in the progress of developing a whole plant transformation system in Olathe Pinto bean variety. In parallel, we are working to build a CRISPR/Cas9 platform that will allow us to use that technology to specifically target the area of interest in the ALS gene via homology-directed repair mechanism. Downstream goals of this project are to apply efficient tissue culture techniques in common bean to developing herbicide resistant cultivars for Canadian agriculture in combination with genome editing.