MOHAN CHAVANARUNA, P. M.2023-01-272023-01-272023-01-17https://krishikosh.egranth.ac.in/handle/1/5810192837ThesisResearch to develop biological control agents against the plant pathogens to replace the synthetic agrochemicals gained the considerable attention. The present study was conducted to assess the potential antagonistic bacteria against fungal pathogens from three different regions of Karnataka viz. Yana caves, Dandeli and GKVK campus Bengaluru. Sixty isolates were screened against Fusarium solani and Sclerotium rolfsii, among them one showed antagonism against Sclerotium rolfsii and three were showing antagonism against Fusarium solani. Further, morphological, biochemical and molecular characterization revealed that Bacillus subtilis strain OTG009 showed inhibition (55.55 %) against Sclerotium rolfsii, similarly Bacillus subtilis strain JC43, Bacillus subtilis strain P and Pseudomonas aeruginosa DSM 50071 showed inhibition (45.55 %, 43.33 %, 63.33 % respectively) against Fusarium solani. The isolates found that were able to produce siderophores(chelating agents).However, only Pseudomonas aeruginosa able to produce HCN which helps in defense against plant pathogens. This established the basis for further investigation. Spectrophotometer analysis showed that the extract showed maximum absorption from 200 nm to 400 nm indicated the present of active compounds. The qualitative analysis of compounds present in the ethyl acetate extract using GCMS revealed the presence of antimicrobial, antifungal, antibacterial compounds. Pseudomonas aeruginosa was effectively inhibiting the pathogen growth in vitro. These beneficial soil microbes can be used for the control of plant fungal diseases caused by Fusarium solani and Sclerotium rolfsii.EnglishThesis