Extracellular enzymes of Fusarium graminearum isolates from different agroecological regions

ALCONADA TERESA,; SGARBI CAROLINA; LORI GLADYS; HOURS ROQUE

Rosario Argentina

Congreso; XLII Reunión Anual SAIB; 2006

Sociedad Argentina de Investigación en Bioquímica y Biología Molecular

F. graminearum is the causal agent of the Fusarium head-blight (FHB), a destructive disease of wheat. In Argentina, under favorable environmental conditions for the occurrence of spike infection, the producing regions were grouped according to grade of damage attributable to this pathogenic fungus in: slight (IV and V regions), intermediate (II region) and serious (I and III regions). In this work, isolates from IV, V and II regions were examined according to the production of different enzyme activities: cellulase (CMCase and ß-glucosidase), hemicellulase (endoxylanase), and pectinase (PGase and PMGase). The isolates were grown in minimum salt medium supplemented with 0.25% glucose, 0.125% citric pectin and 0.125% oat bran as carbon sources and/or enzyme inducers. PGase activity was produced early (after 2 days of incubation) in all the cultures, it was found to be the highest for all the isolates. PMGase was high only for those isolates of the II region. CMCase and endoxylanase activities were particularly found at late stages (after 4 and 7 days of incubation, respectively) and the maximum values obtained were lower than pectinase activities. The in vitro enzyme production of the F. graminearum isolates could suggest that although similar enzymes were detected, their sequential and differential production profile may be related to the fungal aggressiveness.