Isolation and screening of groundnut endophytic bacteria for multiple plant growth promoting characteristics

Abstract

Groundnut is an important oilseed crop. Endophytic bacteria help plant growth and development through various mechanisms. The aim of the present study was to isolate and screen endophytic bacteria from groundnut for multiple plant growth promoting characteristics under in-vitro conditions. A total of 50 morphologically diverse endophytic bacteria were isolated from root and leaf samples of groundnut. These endophytic bacteria were screened for multiple plant growth promoting characteristics such as indole acetic acid (IAA) production, phosphorus, potassium and zinc solubilization, moisture stress tolerance and ACC deaminase synthesizing capabilities. The isolates GEB 32 (3.45µg/ml), GEB 58 (3.36µg/ml) and GEB 62 (3.31µg/ml) showed comparatively higher IAA synthesizing capabilities. Phosphorus, potassium and zinc solubilization was observed in 14, 12 and 9 isolates respectively. The isolates GEB 61, GEB 59 and GEB 48 have recorded maximum phosphorus, potassium and zinc solubilization indices as compared to other isolates. Relatively higher moisture stress tolerance in terms of growth in 30% PEG 6000 amended medium was observed in the isolate GEB 22. On the basis of in-vitro screening 07 best isolates were selected for further studies in pot experiments.