PlantForm | Newsroom | U.S. Patent Office allows PlantForm's patent application for novel approach to boost yields of plant-based protein products

U.S. Patent Office allows PlantForm's patent application for novel approach to boost yields of plant-based protein products

GUELPH, Ont., Aug. 22, 2023 – The United States Patent Office has allowed PlantForm Corporation’s application to patent a novel approach to enhancing yields of plant-based protein products by suppressing post-translational gene silencing.

The application, no. 16/635,402 “Transient Silencing of Argonaute1 and Argonaute4 to Increase Recombinant Protein Expression in Plants,” covers technology that complements and extends the capabilities of PlantForm’s vivoXPRESS® platform and associated glycan engineering techniques.

“With the Notice of Allowance for this patent application, we’ve achieved an important milestone in our IP strategy to extend and strengthen protection for the vivoXPRESS® platform,” said Dr. Don Stewart, PlantForm’s President and CEO. “This novel approach to suppressing the gene-silencing machinery of plants will expand the potential array of therapeutic protein products that we can produce, at low cost, using additional varieties of Nicotiana plants.”

In simple terms, the vivoXPRESS® system works by infiltrating Nicotiana benthamiana with a bacterium containing the genetic sequence of the target protein. This causes the plants to express the protein in their cells as they grow; after five to six weeks, the plants are harvested and the target protein extracted and purified. However, protein expression is always impeded by post-translational gene silencing, part of the plant’s natural defenses against invading pathogens that works by impeding the transfer of genetic material to the host. ARGONAUTE (AGO) proteins play a central role in this process through RNA interference (RNAi). Suppression of RNAi has been demonstrated to improve transient protein expression.

For two decades, the benchmark standard has been to use co-expression of protein P19 to suppress gene silencing and improve protein expression. But while P19-based systems work well with N. benthamiana, P19 may damage other varieties and isn’t suitable for expression of some proteins. This limits the potential hosts that can be used for recombinant protein expression, which is problematic because other Nicotiana species produce greater biomass and therefore may be more cost-effective for large-scale protein production.

The patent application covers PlantForm’s novel approach that shows how high levels of target protein expression can be achieved suppressing AGO1 and AGO4 in the host plants.

“This is an exciting step forward that further demonstrates the potential of our made-in-Canada platform for producing a wide variety of antibody drugs, protein drugs and vaccines, and for making them accessible and affordable worldwide,” Stewart said.


About PlantForm Corporation (
PlantForm Corporation is a biopharmaceutical company focused on the low-cost production of high-value antibody and protein drugs and vaccines using the proprietary vivoXPRESS® plant-based manufacturing platform. The vivoXPRESS® plant expression system produces biologic drugs at a significantly reduced cost compared to standard mammalian cell systems. The platform is fast (drug production in as little as six weeks), versatile and easily scalable. PlantForm’s pipeline features an innovative antidote to ricin exposure, and biosimilar versions of the brand name biologic drugs Lucentis® and Keytruda®Learn more.

Rounded Corners