FUNGICIDAL ACTIVITY OF THE SYNTHETIC PUTRESCINE ANALOG, (E)-1,4-DIAMINOBUT-2-ENE, AND DERIVATIVES

The putrescine analogue, (E)-1,4-diaminobut-2-ene (E-BED), synthesized as the dihydrochloride salt, controlled five economically important crop pathogens, Erysiphe graminis DC fsp. hordei Marchal, Uromyces viciae-fabae (Pers.) Schroet, Botrytisfabae Sardina, Podosphaera leucotricha (Ell. & Ev.) Salm. and Phytophthora infestans (Mont) De Bary. The Z-isomer, Z-BED, was also fungicidal, although less so than E-BED. Post-inoculation treatment with E-BED gave greater control of powdery mildew infection on barley and rust and chocolate spot on broad bean than did pre-inoculation application. It was also effective in vitro against Botrytis cinerea Pers. ex Fr., Pyricularia oxyzae Br. & Cav. and Pyrenophora avenae Ito & Karibay. When P. avenae was grown in the presence of E-BED dihydrochloride at 81.5 mg litre-1, growth was reduced by 58% and there were significant reductions in soluble ornithine decarboxylase (ODC) and S-adenosylmethionine decarboxylase (AdoMetDC) activity. These changes were accompanied by a sevenfold increase in putrescine concentration, a 60% increase in spermine concentration and a 32% reduction in spermidine concentration within the fungal tissue.