Plant growth promoting endophytic bacteria (PGPE) influences the plant growth by various direct mechanisms. To look for efficient PGPE strains having multiple activities, 80 bacterial isolates were isolated from different tissues of rice obtained from major rice growing districts of Tamil Nadu. From 80 isolates, 20 efficient bacterial isolates were selected based on their plant growth promoting traits like production of indole acetic acid (IAA), phosphate solubilizing, hydrogen cyanide (HCN), siderophore and catalase activity. These 20 bacterial isolates of Bacillus showed potential plant growth promoting activity. All selected bacterial isolates in comparison with the control also showed increase in both the shoot and the roots of rice seedlings. PGPE were tested for seed germination and seedling vigor using rice seeds in roll towel method. Among the 20 isolates Bacillus sp. strain EBPBS 4 has multifaceted beneficial characteristics. This strain exhibited the production of 104 Âµg/ml of indole-3-acetic acid (IAA) in tryptophan-supplemented medium. It was able to solubilize 50.6 mg Lâˆ’1 tri-calcium phosphate, and inhibited >70% growth of Sheath blight fungal phytopathogen (Rhizoctonia solani) tested in vitro. It may be an ideal plant growth promoting as well as biocontrol agent, for its integrated use in disease and nutrient management strategies.
Keywords: Bio pesticides, Bacillus, plant growth promoting bacteria.