Molecular characterization and biocontrol-traits evaluation of trichoderma virens tvh3 against fusarium oxysporum, the causal agent of tomato wilt.

Abstract

In attempt to screen for new biological control agents (BCA) with high activity against soil-borne fungal pathogens, an isolate of the BCA Trichoderma virens was obtained, identified using molecular techniques and named TVH3. The antagonistic activities of this isolate were tested against Fusarium oxysporum, a major soil-borne fungal pathogen of diverse crops. Our results revealed that T. virens TVH3 displayed high antagonistic potential against F. oxysporum via different mechanisms to control its prey, such mechanisms include competition for the available space and nutrients, mycoparasitism and production of antimicrobial secondary metabolites including volatile organic compounds (VOCs). The antifungal soluble metabolites in Trichoderma’s culture filtrate were found to be thermal-stable and T. virens TVH3 was found to possess high natural immunity against antimicrobial metabolites in F. oxysporum culture filtrate. In the biocontrol assay, isolate T. virens TVH3 was applied as seed coat on tomato seeds before planting them in heavily infested soil with pathogenic strain of F. oxysporum and the obtained results revealed that such seed treatment had significantly reduced wilt signs on plants and provided the seedlings with effective shield against pathogenic infection.