Resumo

GONZALEZ, Ivonne et al. BIOCHEMICAL CHARACTERIZATION OF PROMISORY ISOLATES OF Trichoderma spp. AS BIOLOGICAL CONTROL AGENTS. I. EXPRESSION OF CHITINASE ACTIVITY. Rev. Protección Veg. [online]. 2010, vol.25, n.1, pp. 58-63. ISSN 2224-4697.

Most of the Trichoderma species fungi are used as biological control agents for the management of the diseases caused by phytopathogen fungi of the genera Phytophthora, Rhizoctonia, Sclerotium, Pythium and Fusarium. It is possible due to the capacity of these fungi to secrete hydrolytic enzymes such as chitinases. Trichoderma isolates present different secretion levels of chitinase enzymes, thus it is of special interest to reckon on indicators that allow selecting the most promissory isolates as biological control agents. In this work, the dynamics of chitinase induction of ten Trichoderma spp. isolate was evaluated in three liquid media: basal medium, basal medium supplemented with chitin 0,5% and basal medium supplemented with gelatine 0,2%. The enzymatic activity was determined in the supernatants at the first, third, fifth and seventh days of the cultures. The isoaltes showed different levels of chitinase activity depending on the culture medium and isolate analyzed. The medium with chitin turned out to be the most advantageous in stimulating chitinase induction and, therefore, for the selection of the best candidates as biological control agents.

Palavras-chave : Trichoderma; chitinases; biological control; biochemical characterization.

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