Expression of Escherichia coli heat-labile enterotoxin B subunit in transgenic tomato (Solanum lycopersicum L.) fruit

We report a feasibility study for expressing the LTB protein (Escherichia coli heat-labile enterotoxin B subunit) via Agrobacterium-mediated transformation of tomato (Solanum lycopersicum L.). We produced five regenerated plants obtained on the selection medium supplemented with an antibiotic. Stable integrations of the LTB gene into the genome of these plants were confirmed by Southern blot hybridization. Western blot analysis showed that only two of the five T₀ transgenic tomato plants expressed the pentameric LTB protein in the fruits. An enzyme-linked immunosorbent assay indicated that these two plants synthesized the LTB protein bound specifically to GM1 ganglioside, suggesting that the LTB subunits formed active pentamers. The LTB protein produced in tomatoes can be a potential candidate for inexpensive, safe, and effective plant-based vaccines.