Based on results from above experiments, we have successfully synthesized a partial SARS-CoV S gene that encodes an antigenic region of the Spike protein. We have introduced the CTB gene and the CTB-S fusion gene into low-nicotine tobacco plants. The presence of the foreign gene in the transgenic plants was confirmed by PCR. Northern blot hybridization demonstrated that the transgene was correctly transcribed in the transgenic plants. The CTB-S fusion protein was detected by western blot. GM1–ganglioside ELISA binding assay demonstrated that the plant-produced CTB-S fusion protein efficiently binds to the mucosal GM1-receptor. Thus, we have built the solid foundation for the development of a plant-derived, orally administered, safe, edible vaccine against SARS infection.