KAUR, MOHINDERKUMARI, MANORMA2018-01-202018-01-202017-12http://krishikosh.egranth.ac.in/handle/1/5810039705ABSTRACT The aim of present study was production and characterization of lytic enzymes i.e. protease and chitinase produced by fluorescent Pseudomonas sp. isolated from the normal and replant sites of apple orchards. Eleven Pseudomonas sp. were isolated from the replant sites of Rauni and Maggota of Shimla district. Four isolated strains of fluorescent Pseudomonas sp. from replant sites of apple were also used for screening of direct and indirect plant growth promoting activities like lytic enzymes (protease & chitinase), siderophores, phosphate solubilization and production of HCN, ammonia, plant growth regulators (auxins, cytokinins and gibberellins), antifungal and antibacterial activity. By 16S rRNA gene characterization, isolates Rn1 and Mgn1 showed 99.0% and 97.0% similarity with Pseudomonas brassicacearum KU139391 and Pseudomonas aeruginosa respectively. The pathogenic fungal isolates from replant sites of orchard at Rauni i.e. RF3 showed 99.0% similarity with Phytopythium litorale and from Maggota i.e. MF5 showed 99.0% similarity with Pythium ultimum by ITS gene sequencing. Optimization of media, time of incubation, temperature, pH, carbon, nitrogen and mineral sources were done for the production and characterization of protease & chitinase from four Pseudomonas strains L (Pseudomonas putida), M (Pseudomonas fluorescens), G and H (Pseudomonas aeruginosa), which were also used for mass multiplication of inoculum for field trials. Purification of protease and chitinase was done through Sephadex G-75 column chromatography. Through SDS-PAGE electrophoresis, the molecular weight of Protease was recorded as 31.0 to 43kDa and 26.0 to 38.0kDa for chitinase. This study also reported significant role of protease & chitinase in antagonistic activity against Dematophora necatrix, Phytopythium litorale and Pythium ultimum. Lytic enzymes (protease and chitinase) are responsible for the lysis and hyperparasitism of antagonists against deleterious fungal and bacterial pathogens. Lytic enzymes along with other plant growth promoting activities may be the reasons for better establishment and growth promotion of replanted apple. Treatments with bioformulations of consortia were found to be more effective in growth and establishment of replanted apple. Therefore these strains can be exploited for the management of replant problem of apple.ennullThesis