Strain Improvement of Trichoderma Harzianum by Uv Mutagenesis for Enhancing It’s Biocontrol Potential against Aflotoxigenic Aspergillus

Trichoderma is an opportunistic, avirulent plant symbiont. Chitin is the main structural component of fungi, enzyme responsible to metabolize the chitin and various techniques to enhance the chitinolytic enzyme production at the genetic level are receiving great attention to develop the efficient biocontrol agent. UV mutagenesis was found to be one of the novel strategy for developing Trichoderma mutants with enhanced chitinolytic activity. Four mutant strains were obtained from the wild T. harzianum, after UV treatment of different time period ranging from 2min, 4min, 6min, 8 min. Chitinase overproducing mutants were selected by growing on basal chitinase detection medium, based on the diameter of purple color zone formation around the colony in a shorter time. Selected mutants were tested for in vitro inhibition of test pathogen (A. flavus and A. parasiticus) by using various plate culture techniques (dual culture, pathogen at center, inverted plate technique) for their bio-efficacy.