Translocation of Insecticidal Bt Protein in Transgrafted Plants

Transgrafting constitutes a technique involving the integration of genetically modified (GM) and non-GM plant organisms. Typically, edible components derived from non-GM scions are categorized as non-GM food products, attributed to the absence of exogenous genetic material within their respective genomes. Non-GM food status could be compromised if proteins translocated across the graft interface. We investigated the movement of insecticidal Bacillus thuringiensis (Bt) crystal proteins, widely utilized in GM crop species. Tobacco plants engineered to express the Cry1Ab gene exhibited trace levels of Cry1Ab protein accumulation. In transgrafted plants, translocated Cry1Ab protein originating from GM rootstocks was detectable within scion foliar tissues but not within the seeds obtained from the non-GM scion. This result unequivocally demonstrates the capacity for Bt protein translocation from rootstocks to scions yet indicates a constrained distribution confined to scion tissues relatively close to the graft junction. While regulatory considerations necessitate a thorough appraisal of potential risks associated with Bt proteins, the results shown here facilitate the commercialization of the edible components as non-GM food products.