Pectinolytic enzyme production by Colletotrichum truncatum, causal agent of soybean anthracnose

A.M. RAMOS; M. GALLY; C. GARCÍA; L. LEVIN

REVISTA IBEROAMERICANA DE MICOLOGIA

ASOCIACION ESPANOLA MICOLOGIA-AEM

Año: 2010 vol. 27 p. 186 - 190

1130-1406

Colletotrichum truncatum is the most common pathogenic fungus associated with soybean anthracnose, a prevalent disease in Argentina. Pectinolytic enzymes are involved in the pathogenicity of a wide range of plant pathogenic fungi. Objectives: By exploring pectinolytic enzyme production, contribute to the physiological characterization of Argentinean Colletotrichum strains isolated from diseased soybean plants from different geographic locations, as a preliminary step to establish the biological role of the pectinolytic enzymes in the Colletotrichum spp.-soybean system, yet unknown. Methods: Ten strains were screened for in vitro pectinolytic enzyme production on a defined medium based on pectin as carbon source. Results: All isolates were able to grow in this medium and polymethylgalacturonase (PMG), polygalacturonase (PG) and pectin lyase (PL) activities were detected. On the whole, the peak of polygalacturonases activities preceded the day of maximum growth, while PL activity reached its highest level afterwards. Strain BAFC 3097 (from Santa Fe province), yielded high titles of the three enzymes (1.08 U/ml PG, 1.05 U/ml PMG, 156 U/ml PL), after a short incubation period (7-10 days). Low synthesis of polygalacturonases in cultures containing glucose as unique carbon source suggests that these enzymes are constitutive in contrast to PL that was not detected. Conclusions: The disparity observed in enzyme production among strains cannot be related to fungal growth, since no major differences in mycelial yield were found; it was not connected with their geographic origin, but might be associated with differences in virulence among strains, not yet evaluated.