NATARAJA KARABA, NPALLAVI, N2023-01-042023-01-042022-12-07https://krishikosh.egranth.ac.in/handle/1/5810191106Endophytes, which include fungi and bacteria are present ubiquitously and reside in the intracellular spaces of the plants symbiotically. Endophytes have been gainingimportance for their role in improving stress tolerance in the host plants. In the present study, fungal endophytes (FE) isolated from harsh environmental conditions were employed to enhance drought and salinity stress tolerance in tomato (Solanum lycopersicum L.). The fungi belonging to the Fusarium genus were found to be predominant as indicated by morphological and molecular analysis. Among ten endophytes evaluated, four endophytes sustained growth under PEG- and NaCl-induced stress conditions. Tomato varieties namely, Arka Vikas, Arka Saurabh, Arka meghali and Arka Abha were screened under PEG-8000 and NaCl-induced stresses and Arka Saurbhwas found to be stress-sensitive. Colonization of F. incarnatum (K-23) and Fusarium sp.,(P-10) significantly improved seedling growth under PEG stress whereas F. equiseti (SF-5) and F. incarnatum (K-23) enhanced tolerance for NaCl-induced stress. The best two fungi were further evaluated under rainout shelter conditions for improving drought tolerance in tomato. Colonization of K-23 and P-10 improved photosynthesis and plant growth in tomato under non-stress conditions followed by yield traits and qualityparameters under drought stress conditions. The select FEs also improved the growth of tomato under protected conditions. However, there was no significant difference in yield under-protected and field conditions. Hormone profiling of the plants colonized with K-23 and SF-5 indicated a significantly higher content of auxin (IAA) and gibberellic acid (GA3) under stress conditions. Global metabolome analysis indicated a greater number of differentially accumulated metabolites in endophyte-enriched seedlings under stressful conditions. This study demonstrated that habitat-adapted endophytes could be effectively used to improve abiotic stress tolerance in a sensitive variety of tomato.EnglishThesis