GE-Low PPO5 potatoes were developed by using disarmed Agrobacterium to transiently deliver transcriptional activator-like effector nuclease (TALEN) into plant cells, generating targeted knockouts through the introduction of a small, targeted mutation in the endogenous ppo5 gene (also known as pot32).

As a result of this small mutation, these potatoes produce reduced PPO5 protein, a polyphenol oxidase (PPO) enzyme that is responsible for enzymatic darkening and discoloration in potato tubers (black spot).

The absence of the binary vector and presence of the desired gene knockout mutation is confirmed by PCR, T7 endonuclease I assay, and Southern blot analysis. No genetic material used to create the knockouts is present in the final potato plants.