Plant hormones and plant virus diseases. The auxins

Systemic virus infection impairs the steady state of auxin hormone in plant with consequent morphogenetic alterations. Most reports indicate a reduction of auxin activity in diseased plants, generally associated with stunting, but a substantial increase in auxin activity has sometimes been observed in cases of severe symptomatology. Treatments of virus-diseased plants with exogenous auxins may inhibit virus replication and reduce symptom severity, although results have been obtained by empirical application and must therefore be considered with caution. There is no information on how virus infection alters auxin metabolism or how this alteration affects both plant growth and development. The considerable progress reached in auxin biochemistry now allows more accurate re-investigations of this important relationship.