Influence of Protoplast Fusion in Trichoderma Spp. on Controlling Some Soil Borne Diseases

Abstract

Protoplasts from Trichoderma harzianum NBAII Th 1 and T. viride NBAII Tv 23 were isolated using lysing enzymes. Protoplast fusion of T. harzianum and T. viride was carried out. The fused protoplasts generated and 21 fusant isolates were used to study their antagonistic activity and RAPD-PCR characterization in comparison with their parents. Among the fusant isolates, F7 isolate produced maximum growth inhibition pathogen (one and half-fold increase as compared to the parent strains). All the tested fusants isolates exhibited increased antagonistic activity against Fusarium oxysporum than the parent strains except fusant F21. Specific results for fingerprinting were obtained by the seven primers of RAPD. These markers produced different fragment patterns with varied number of bands and yielded a total of 79 distinct bands. Polymorphic bands came to be 16.5% whereas monomorphic bands came to be 83.5%. Moreover, the OPO-13 primer has showed the highest polymorphism 35.3%. While, the OPA-16 primer has shown the lowest polymorphism 9.0%. The Dendrogram based on RAPD marker results grouped the two parent strains and twenty-one fusants into two different clusters with about 83% genetic similarity. The first cluster contained the two parent strains and twenty fusants, and the second cluster contained the fusant F2. Our results in this study suggested that the protoplast fusion technique is useful for developing the superior hybrid strains and enhance antagonistic activity of Trichoderma spp. against tested pathogenic fungi.