Disruption of CYP88B1 by transcription activator-like effector nuclease in potato and potential use to produce useful saponins

Potatoes produce steroidal glycoalkaloids (SGAs), toxic secondary metabolites associated with food poisoning. SGAs are synthesized by multiple biosynthetic enzymes. Knockdown of the CYP88B1 gene, also known as PGA3 or GAME4, is predicted to reduce toxic SGAs and accumulate steroidal saponins. These saponins not only serve as a source of steroidal drugs but are also anticipated to confer disease resistance to potatoes. In this study, we employed transcription activator-like effector nucleases (TALENs) for genome editing to disrupt CYP88B1. We introduced the TALEN expression vector via Agrobacterium-mediated transformation into seven potato lines. In six of these lines, disruption of the CYP88B1 gene was confirmed. Liquid chromatography-mass spectrometry analysis revealed that SGAs were reduced to undetectable levels, corroborating the accumulation of steroidal saponins observed in previous knockdown studies. Our findings demonstrate the feasibility of generating low-toxicity potato lines through CYP88B1 gene disruption using genome editing techniques.