Analysis of the beta-1,3-Glucanolytic System of the Biocontrol Agent Trichoderma harzianum.
The biocontrol agent Trichoderma harzianum IMI206040 secretes beta-1,3-glucanases in the presence of different glucose polymers and fungal cell walls. The level of beta-1,3-glucanase activity secreted was found to be proportional to the amount of glucan present in the inducer. The fungus produces at least seven extracellular beta-1,3-glucanases upon induction with laminarin, a soluble beta-1,3-glucan. The molecular weights of five of these enzymes fall in the range from 60,000 to 80,000, and their pIs are 5.0 to 6.8. In addition, a 35-kDa protein with a pI of 5.5 and a 39-kDa protein are also secreted. Glucose appears to inhibit the formation of all of the inducible beta-1,3-glucanases detected. A 77-kDa glucanase was partially purified from the laminarin culture filtrate. This enzyme is glycosylated and belongs to the exo-beta-1,3-glucanase group. The properties of this complex group of enzymes suggest that the enzymes might play different roles in host cell wall lysis during mycoparasitism.
Vázquez-Garcidueñas
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S
Centro de Investigación y Estudios Avanzados, Unidad de Biotecnología e Ingeniería Genética de Plantas, Irapuato, Gto., 36500, and Instituto de Investigación en Biología Experimental, Facultad de Química, Universidad de Guanajuato, Guanajuato, Gto., 36000, Mexico.
Leal-Morales
C A
CA
Herrera-Estrella
A
A