Molecular heterozygosity and genetic exploitations of Trichoderma inter-fusants enhancing tolerance to fungicides and mycoparasitism against Sclerotium rolfsii Sacc.

Protoplast fusion is an imperative tool to develop Trichoderma inter-fusants having desire traits through genetic manipulation. Study designed to develop diverse Trichoderma fusants for fungicide tolerance (Mancozeb, Thiram, Tebuconazole, and Carbendazim) and enhanced mycoparasitic activity against Sclerotium rolfsii sacc. The mycoparasitic T. virens NBAII Tvs12 and fungicide tolerant T. koningii MTCC 796 were utilized for protoplast fusion. The derived inter-fusants were subjected to diploidization using d-camphor in minimal media followed by successive three sub culturing onto potato dextrose agar to obtain 36 stable fusants. The stable fusants were employed for conidial size, fungicide tolerance, mycoparasitism, gene specific SSR amplification and molecular heterozygosity analysis. The results explained that 22 homozygous mutants illustrated characteristic of either one parental strain and 14 heterozygous recombinants depicted traits of both parental strains. The antagonistic activity of fusants against S. rolfsii depicted highest growth inhibition (87.91%) by potent inter-fusant (Fu 21) with improved fungicide tolerance capacity. The molecular study revealed highest observed heterozygocity (0.544), coefficient of gene differentiation (0.526) and gene flow (0.387) by Fu 21 indicating better genetic exploitation of parental strains into that fusant with good genetic purity. Principal coordinate analysis of fusants and parental strains exhibited 65.07% total variation and confirmed the scattering pattern matched with UPGMA clustering pattern. The stable heterozygous Fu 21 derived from inter-fusion between Tvs 12 and MTCC 796 might be useful to practice eco-friendly bioformulation tolerance to fungicides for effective integrated stem rot disease management in groundnut.