Endogenous changes in citokinin activity in systemically virus-infected plants

Viral diseases may alter cytokinin activity in plants, an effect associated with morphological and physiological changes. Experimental evidence indicates that the level of cytokinins may be both reduced or increased depending on different viral diseases. Circumstantial evidence suggests a change in virus-diseased plants showing specific alterations such as tumors and disorders in carbon partitioning and chlorophyll metabolism. The knowledge reached on cytokinin changes is not yet adequate to the importance of their role during viral pathogenesis. Furthermore, unclear results are available on the effect of cytokinins on virus replication. There is little information on how systemic virus infection alters cytokinin metabolism and no information on how this alteration can affect plant metabolism. Nevertheless, a possible control of some viral diseases by biomanipulation of plants to modify the endogenous levels of such hormone may be suggested, provided that higher levels of cytokinins do not increase the rate of virus replication.