EFFECT OF POLYAMINE BIOSYNTHESIS INHIBITORS ON GROWTH AND PATHOGENESIS OF Ustilago maydis

GÁRRIZ, A; GONZALEZ, ME; MARINA, M; RUIZ-HERRERA, J AND RUIZ, OA.

Pinamar. Buenos Aires. Argentina

Congreso; 10th Congress of PABMB and 41th Reunión Anual SAIB; 2005

SAIB

Polyamines (putrescine, spermidine and spermine) are ubiquitous polycationic compounds that have demonstrated to be essential for growth and development of all organisms. Inhibitors of its biosynthesis have largely been tested on its capability to prevent fungal plant diseases. In this work, we evaluated the effect of well-known polyamine biosynthesis inhibitors on growth, differentiation and pathogenesis of Ustilago maydis, the causal agent of the corn smut disease. This fungus shows a dimorphic transition during its life cycle, that is, grows saprophytically in a yeast-like form but become filamentous when two compatible cells fuse at plant surface, a process that implies conjugative tube formation. All the inhibitors demonstrated to affect vegetative growth as well as pH-induced dimorphic transition. Interestingly, the inhibitors also inhibited conjugative tube formation but mating of compatible cells and mycelial formation was not necessarily prevented. Finally, application of inhibitors before inoculation of Arabidopsis thaliana seedlings demonstrated to favor plant infection, suggesting an effect of inhibitors on plant polyamine metabolism. Posible implications and potential use of inhibitors to prevent fungal plant diseases are discussed.