The envelope G glycoprotein is the sole surface glycoprotein of spring viraemia of carp virus. It mediates virus attachment to host-cell receptors, facilitating viral entry via receptor-mediated endocytosis and membrane fusion. The G protein is the principal viral antigenic determinant, responsible for the infectivity and serological properties of the virus. Due to its surface exposure, it is the primary target of neutralizing antibodies generated during infection and induces protective immune responses. Owing to these properties, the G protein is widely utilized as a vaccine antigen in experimental approaches, including DNA vaccines, recombinant protein vaccines, viral-vectored vaccines, and other oral vaccines for protection against spring viraemia of carp virus.