Transgenic Sweetpotato (Ipomoea batatas) Expressing Spike Gene of Porcine Epidemic Diarrhea Virus

Porcine epidemic diarrhea virus (PEDV) causes acute enteritis in pigs of all ages and is often fatal for neonates. In order to develop sweetpotato plants expressing PEDV antigen, we constructed the vector expressing spike gene of PEDV under the control of sweetpotato sporamin promoter or constitutive CaMV 35S promoter. The spike protein region of PEDV was synthesized by PCR and linked to each promoter, Transgenic sweetpotato [Ipomoea batatas (L.) Lam. cv. Yulmi] plants were developed from embryogenic calli following Agrobacterium tumefaciens-mediated transformation. The co-cultured embryogenic calli transferred to selective MS medium containing 1 mg/L 2,4-D, 100 mg/L kanamycin, and 400 mg/L claforan. These embryogenic calli were subcultured to the same selection medium at 3 weeks interval. Kanamycin-resistant calli transferred to hormone-free MS medium with kanamycin gave rise to somatic embryos and then converted into plantlets in the same medium. Southern blot analysis confirmed that the spike gene of PEDV was inserted into the genome of the sweetpotato plants. RT-PCR revealed that the spike gene of PEDV was highly expressed in transgenic sweetpotato plants.