Isolation, screening, characterization of PGPR and antagonism assay against Alternaria solani

A total six bacterial isolates were screened for different plant growth promotion activities i.e. phosphate solublization, IAA production, siderophore production. Six isolates were designated as TR25, TR21, TR22, TR23, TR24 and TR15, and characterized. In the present work, five bacterial isolates were positive for IAA production and siderophore production and one (TR25) isolates were found to be positive for phosphate solublization. Most of the isolates grown best under the temperature range of 20–28°C when compared to 10 and 37°C and very few grew at 45°C, Furthermore, most of the PGPR isolates shown antifungal activity against Alternaria solani. It was therefore, suggested that the use of PGPR isolates such as TR25, TR21, TR15, and TR22 may be used as inoculants/biofertilizers which are beneficial for tomato cultivation as they enhanced growth of tomato due to production of Indole acetic acids, phosphate solublization and also having antifungal activity against phytopathogenic fungi.