Title:	Tracking extra-celullar enzyme production by Trichoderma harzianum in the rhizosphere.
Authors:	FAULL, J. L. MELO, I. S. de GRAEME-COOK, K. A.
Affiliation:	EMBRAPA-CNPMA; ITAMAR SOARES DE MELO, CNPMA.
Date Issued:	1998
Citation:	In: SIMPÓSIO DE CONTROLE BIOLÓGICO, 6., 1998, Rio de Janeiro. Anais: conferências e mesas-redondas. Rio de Janeiro: FIOCRUZ/EMBRAPA, 1998. p.361.
Description:	The exact role of extracellular enzyme production in the activities of Trichoderma harzianum as a biological control agent are much debated. Production of such enzymes as cellulase, proteinase, endoglucanase, (glucosidase and chitinase has been linked to biological control in vitro experiments (Elad et al, 1982, Ahmad & Baker, 1988 a,b) bur it has been difficult to prove that these enzymes are important in vivo. Baker (1991) demonstrated that mutant strains of Trichoderma with improved rhizosphere competence had higher extracellular cellulase production than wild types strains, and he speculated that enhanced cellulase production might lead to better utilisation of rhizosphere substrates and thus improved colonisation of the resource. However, it has been recently shown that rhizosphere competence of Trichoderma strains is not always associated with improved in vitro production of extracellular enzymes (de Melo, Faull, J, L, and Graeme-Cook, 1997). In order to extend this work to the soil environment we have developed a sensitive, quantifiable assay for extracellular enzymes that uses a fluorescent substrate to detect enzyme activity in soil. Using a number of different strains of Trichoderma with known in vitro extra-cellular enzyme production patterns (both high and low) we will demonstrate differences in the production of enzymes in the rhizosphere with varying soil depth. We will attempt to relate these differences to the root colonisation ability of the Trichoderma strain.
Thesagro:	Controle Biológico Enzima Trichoderma
Type of Material:	Resumo em anais e proceedings
Access:	openAccess
Appears in Collections:	Resumo em anais de congresso (CNPMA)