Mutagenesis and inter-specific protoplast fusion between Trichoderma koningii and Trichoderma reesei for biocontrol improvement

Abstract

The present work aimed to apply mutagenesis and inter-specific protoplast techniques of two locally isolated Trichoderma spp. to enhancement their biocontrol abilities against some important plant fungal pathogens which cause root-rot and damping-off diseases that attacking different crops. A combination of UV-light and nitrate treatment induced seven mutants (T. koningii, 3 mutants and T. reesei, 4 mutants). The inter-specific protoplast fusion between T. koningii and T. reesei gave fusion frequency reached 1.25% and thirteen fusants were isolated. In vitro bioassay of the parental Trichoderma spp., their selected mutants and fusants indicated the effective of both T. koningii and T. reesei in suppressive the tested fungal pathogens. On the other hand, most of the selected mutants and fusants showed superiority in their antagonistic activity against these pathogens than their parental strains. the superiority in biological control activities of the selected mutants or fusants than their parents against the tested pathogens may be due to the effect of the genetic treatments (i.e. mutagenesis an protoplasts fusion) on their genetic back ground to be varied that allow to change in genetic control of antifungal metabolites production to be more effective. The results indicated that mutation and protoplast fusion techniques are successful tools to enhance the antagonistic effects of Trichoderma species against several fungal plant pathogens.