LAKSHMINARAYANA REDDY), C. N.NANDAN, M2023-01-052023-01-052021-03-31Th-12894https://krishikosh.egranth.ac.in/handle/1/5810191276Studies on fungal endophytes against soil-borne fungal pathogens of tomato was conducted in-vitro and in-vivo. Thirty-five fungal endophytic OTUs were isolated from leaf, stem and root tissues of Tridax procumbens, Cassia tora and Parthenium hysterophorus and one potential fungal endophyte from previous studies, i.e.,Trichoderma asperellum isolate 1 (TA1) were evaluated against targeted pathogens, Sclerotium, Fusarium and Rhizoctonia infecting tomato by dual culture technique.OTU’s showing more than 50 per cent inhibition against targeted pathogens and three pathogens mentioned above were taken for further characterization through ITS region sequencing and analysis. To decipher the mechanism involved by potential endophyte Trichoderma asperellum isolates against selected pathogens, disc diffusion assay and double Petri dish assay was conducted. Further, endophytes showing positive inhibition of pathogen in these assays were processed for LC-ESI-MS/MS and GC-MS analysis and diffusible and volatile compounds involved in interaction were identified, respectively, which showed the presence of antimicrobial diffusible and volatile compounds produced by isolates of T. asperellum. To confirm the antimicrobial nature of diffusible compounds in-silico docking analysis was performed, which revealed the potentiality of diffusible compounds in binding to β-tubulin and inhibiting the targeted pathogens. Scanning electron microscopic studies showed the parasitizing behaviour of T. asperellum against Rhizoctonia and Fusarium pathogens. Tomato seed primed with endophyte, T. asperellum showed delayed in the onset of Sclerotium wilt in comparison with control plants. The gene expression studies using qRT-PCR analysis for seven genes involved in resistance pathways showed increase in their expression indicated the role of T. asperellum in inducing the plant systemic resistance.EnglishThesis