Schematic diagram of the SARS-CoV-2 genome [95]. The genomic structure of SARS-CoV-2 is 5′-UTR-orf1a-orf1ab-S (Spike)–E (Envelope)-M (Membrane)-N (Nucleocapsid)-3′UTRpoly (A) tail. Accessory genes are interspersed within the structural genes at the 3′ end of genome. The pp1a protein encoded by the orf1a gene and the pp1ab protein encoded by the orf1ab gene contains 10 nsps (nsp1-nsp10). The pp1ab protein also includes nsp12-nsp16.