Relationship between in vitro cellulase production of uv-induced mutants of Trichoderma harzianum and their bean rhizosphere competence

Strains of Trichoderma harzianum with either elevated or reduced production of cellulase-complex enzymes β-glucosidase and endoglucanase were constructed using uv-light mutagenesis. In tests for rhizosphere competence two of the cellulase minus strains were found to have significantly enhanced rhizosphere competence, whilst two cellulase overproducers were found not to colonize either the rhizosphere or rhizoplane of bean plants. These results indicate that rhizosphere competence of Trichoderma strains is not always associated with extracellular enzyme production.