Fig. S1.

Check of cross-reactivity of designed primer among Betacoronavirus. RNA of SARS-CoV and murine hepatitis virus (MHV) were extracted with the QIAamp Viral RNA kit, and genomic RNA of SARS-CoV-2 was purchased from ATCC (VR-1986D™). cDNA was synthesized with the High-Capacity cDNA Reverse Transcription Kit. 3 μg of cDNA was used for templates and PCR-amplified with Ex Taq polymerase. A gel electrophoresis of the amplified products was performed to visualize the PCR products under ultraviolet light.