Transmission by a vector is a common feature among viruses, especially plant viruses. While animal arboviruses infect literally their vector ("biological transmission"), plant viruses are mostly transmitted "mechanically". This mode of transmission is seemingly quite simple - the virus contaminates the vector mouthparts and subsequently is mechanically inoculated into new healthy hosts. In fact, the process involves astonishingly complicated virus-vector interactions that have been the focus of many studies. Nowadays, this phenomenon is considered far from being purely "mechanical" and has been renamed "non-circulative" transmission. In addition to specific ligand/receptor-like interactions between the virus and the vector, sophisticated regulatory mechanisms occur between the host cell and the virus, which seem to be dedicated exclusively to successful virus transmission. The aim of this review is to illustrate, using Cauliflower mosaic virus as a model, the remarkable intricacy of the noncirculative mode of transmission, and possibly instigate analogous research for animal viruses.
Keywords: CaMV; aphid; insect; non-circulative transmission; plant virus; vector-transmission.