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

SANNAZZARO A, ALVAREZ C, MENÉNDEZ A, PIECKENSTAIN FL, ALBERTÓ E & RUIZ OA.

Bariloche, Argentina

Congreso; XXXIX Reunión Anual de la Sociedad Argentina de Investigación en Bioquímica y Biología Molecular; 2003

Sociedad Argentina de Invesitigación en Bioquímica y Biología Molecular

The aim of the present study was to increase the knowledge onpolyamine metabolism in AM fungi and to determine whetherinhibitors of polyamine synthesis (which could be used asfungicides) may cause negative effects on spore germination andhyphal growth of Gigaspora rosea. In vivo decarboxylation ofradioactive substrates, showed that the ODC pathway is activeand ADC activity occurs in G. rosea spores. Results showed thaturease is active during spore germination and provided evidenceon the activity of NCPase, downstream the ADC. Effect ofpolyamine synthesis inhibitors on free polyamine content of spores,germination and germinating tube growth was studied. Spermineand spermidine were reduced by DFMA at concentrations 0.05and 0.5 mM, whereas CHA or DFMO did not affect spermine andspermidine levels. DFMA and DFMO, either alone or incombination, and putrescine, exerted no significant effects on sporegermination at any of the assayed concentrations. In contrast, CHAreduced spore germination by far than 70%. On the base of ourresults, the use of polyamine biosynthesis inhibitors to controlfungal pathogens would not affect germination and growth of G.rosea.