Ornithine and arginine decarboxylase activities and effect of some polyamine synthesis inhibitors on Gigaspora rosea germinating spores

SANNAZZARO ANALÍA, ÁLVAREZ CORA, MENÉNDEZ ANA, PIECKENSTAIN FERNANDO, ALBERTÓ EDGARDO, RUIZ OSCAR

San Carlos de Bariloche, Argentina

Congreso; Sociedad Argentina de Bioquímica y Biología Molecular; 2003

Sociedad Argentina de Bioquímica y Biología Molecular

The aim of the present study was to increase the knowledge on polyamine metabolism in AM fungi and to determine whether inhibitors of polyamine synthesis (which could be used as fungicides) may cause negative effects on spore germination and hyphal growth of Gigaspora rosea. In vivo decarboxilation of radioactive substrates, showed that ODC pathway is active and ADC activity occurs in G. rosea spores. Results showed that Urease is active during spore germination and provided evidence on the activity of NCPase, downstream the ADC. Effect of polyamine synthesis inhibitors on free polyamine content of spores, germination and germinating tube growth was studied. Spermine and spermidine were reduced by DFMA at concentrations 0.05 and 0.5mM, whereas CHA or DFMO did not affect spermire and spermidine levels. DFMA and DFMO, either alone or in combination, and putrescine, exerted no significant effects spore germination at any of the assayed concentrations. In contrast, CHA reduced spore germination by far than 70%. On the base of our results, the use of polyamine biosynthesis inhibitors to control fungal pathogens would not affect germination and growth of G. rosea.