EFFECT OF ALLOPURINOL TREATMENT ON THE DEVELOPMENT OF RUST DISEASES OF KIDNEY-BEAN, BROAD-BEAN AND WHEAT PLANTS

The effect of a xanthine oxidase (XO) inhibitor, allopurinol, was stud ied in three host-rust interactions. Application of allopurinol in an incompatible interaction (wheat- Puccinia recondita f. sp. tritici) di d not significantly alter symptom expression nor result in an increase in lipid peroxidation (LP) and electrolyte leakage as compared to non -treated control plants. On the other hand, application of allopurinol in three compatible host-rust interactions suppressed, in a concentra tion-dependent manner, the formation of uredospores which was accompan ied by a transient increase in electrolyte leakage and LP during the b iotrophic fungal growth (5-6 days after infection). These results sugg est that (i) allopurinol can inhibit fungal growth in later developmen tal stage(s) developing only in compatible hosts and (ii) XO is not th e primary source of the generation of reactive oxygen species (ROS) in incompatible rust combinations.