The cDNAs were then in vitro transcribed to the full-length RNA transcripts using a mMessage mMachine T7 transcription kit (Ambion, Austin, CA, USA) and immediately electroporated into 800 μL of 107 cells/mL Vero cells in RNase-free phosphate buffered saline (PBS) along with 5 μg of PEDV nucleocapsid (N) transcripts.