INVITRO EFFECTS OF THE POLYAMINE BIOSYNTHESIS INHIBITOR, ALPHA-DIFLUOROMETHYLORNITHINE, ON ORNITHINE DECARBOXYLASE ACTIVITIES FROM 3 PLANT PATHOGENIC FUNGI

The effects of alpha-difluoromethylornithine (DFMO) on in vitro ornithine decarboxylase (ODC) activities from three plant pathogenic fungi, Pyrenophora avenae, Pyricularia oryzae and Uromyces viciae-fabae, were studied. DFMO concentrations from 0.01 to 1.0 mmol/l produced no significant effects on ODC activities from the three fungi. However, increasing the DFMO concentration to 5 mmol/l produced a substantial reduction in in vitro ODC activity from Pyre. avenae. The ODC inhibitor, alpha-monofluoromethylornithine (2 mmol/l), significantly reduced in vitro ODC activity from Pyre. avenae, whereas RR-methyl acetylenic putrescine, an ODC inhibitor based on putrescine, produced no significant effect on the fungal enzyme.