Fungicidal Activity of Two Spermidine Analogues

The potential use of polyamine analogues as inhibitors of polyamine biosynthesis to control plant pathogenic fungi is well established. However, all of this information relates to the use of putrescine analogues and no data exist for spermidine analogues. It! the present work, two spermidine analogues. Nʹ- and N^-acetylspermidine were evaluated against powdery mildew on barley. Post-inoculation treatments reduced infection by 59.7% and 51.5%. respectively. Since the barley powdery mildeu fungus cannot be grown axenically. mode of action studies were undertaken using the oat leaf-stripe pathogen Fyrenophora avenae. Neither of the analogues had any effect on polyamine biosynthesis in P. avenae grown in vitro. .Although the tnechanism(s) by which inhibitors affect in vivo fungal growth and in vitro growth may differ, it is unlikely that the antifungal properties of the analogues are the result of a perturbation in polyamine biosynthesis