Compared to conventional expression systems, such as microbial fermentation and mammalian cell cultures, plant production systems are inexpensive, easily scalable, free from human pathogens and offer the potential for direct oral administration.

Tobacco has the most established history for the production of recombinant proteins because it is readily amendable to genetic engineering and has a high biomass yield. Furthermore, the tobacco expression platform is based on leaves, which removes the need for flowering, significantly reducing the potential for gene leakage into the environment through pollen or seed dispersal. Most importantly, tobacco is a nonfood, nonfeed crop, which minimizes regulatory barriers by eliminating the risk of plant-made recombinant proteins entering the food chain.