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


OBJECTIVE
To explore pectinolytic enzyme production in Argentinian 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 (1.08U/ml PG, 1.05U/ml PMG, 156U/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 with PL, which 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.
Ramos
Araceli Marcela
AM
Dpto. de Biodiversidad y Biología Experimental, Facultad de Ciencias Exactas y Naturales, PROPLAME-PRHIDEB-CONICET, Universidad de Buenos Aires, Argentina. laulevin@gmail.com
Gally
Marcela
M
García
María C
MC
Levin
Laura
L
D020231:Colletotrichum / Q000201:enzymology*; D010368:Pectins / Q000378:metabolism*; D010935:Plant Diseases / Q000382:microbiology; D013025:Glycine max / Q000382:microbiology*
D010368:Pectins