Economic Significance of Satellites

Plant viruses are responsible for many economically important crop diseases worldwide. The viruses themselves cause the majority of these diseases but in a number of cases very severe or new disease symptoms are associated with a satellite component of the virus. Economic losses attributable to the viral satellite are difficult to separate from those due to the virus, with the exception of few cases. However, since host genetic determinants for symptoms induced by either DNA or RNA viral satellites are beginning to be delineated in an increasing number of records, it is expected that new data will be available soon to dissect the contribution of the viral infection to the disease from that of its satellite. An account is given of economic losses caused by begomoviruses in association with a recently discovered essential DNA-Beta satellite component, and by groundnut rosette virus and cucumber mosaic virus in association with harmful variants of their satellite RNAs.