Antifungal activity and polyphasic characterization of endophytic bacterial isolates obtained from Shamba (Oroxylum indicum), an ethnomedicinal plant of Manipur, India

A total of 57 isolates were obtained from root, stem and leaf samples of Oroxylum indicum. All the isolates were tested for antifungal activity against test fungal pathogens, Rhizoctonia solani (MTCC 4633) and Pyricularia oryzea (MTCC1477). Among 57, 8 (OInL1, OInL6, OInL11, OInL14, OInS13, OInS20, OInR13 and OInR15) and 11 isolates (OInL1, OInL6, OInL7, OInL11, OInL13, OInL14, OInS8, OInS20, OInR13, OInR17 and OInR1) exhibited antifungal activity against Rhizoctonia solani (MTCC 4633) and Pyricularia oryzea (MTCC1477) respectively. All isolates were also characterized for their polyphasic characteristics. Growth of the isolates was checked at different pH values (3, 4, 7, 9 and 10) and different salt (NaCl) concentrations (0, 2, 4, 6 and 8 % w/v). Optimal growth was observed at alkaline pH (7, 9 and 10) as growth was poor in acidic condition. Of 57 isolates, 56 grew well in all NaCl concentrations ranges tested except OInS19 which grew poorly with or without NaCl. Among 57 isolates, only one (OInS19)and 19 isolates (OInL1, OInL4, OInL6, OInL7, OInL11, OInL12, OInL13, OInL14, OInS2, OInS8, OInS20, OInR8, OInR12, OInR13, OInR14, OInR15, OInR16, OInR17 and OInR18) were found positive in MR and VP tests respectively. Furthermore, indole production, catalase activity, gelatin and starch hydrolysis test were performed for each bacterial isolate.