In the former, the coat protein (CP) of the virus has been observed to interact directly with the binding sites (receptors) present in the stylet of the aphid; in the latter mechanism, an additional non-structural protein namely HC-Pro (helper component proteinase) induces the binding between CP and the aphid receptor component, thus creating a reversible “molecular bridge” that leads to effective infection by the aphid vector. The gene discussed is CP; the disease is infection.