Characterisation of a psychrotolerant plant growth promoting Pseudomonas sp strain PGERs17 (MTCC 9000) isolated from North Western Indian Himalayas

A psychrotolerant, Gram negative, rod shaped, plant growth promoting bacterium (PGPB) was isolated from high altitude of North Western Indian Himalayas. The identity of the bacterium was confirmed by morphological, biochemical and sequencing of the 165 rRNA gene. The sequence analysis revealed maximum similarity with Pseudomonas vancouverensis. It exhibited tolerance to 3 wide pH range (5-12; optimum 7.0) and salt concentrations up to 5% (w/v). The isolate produced 8.33 and 1.38 mu g/ml of IAA at 15 degrees C and 4 degrees C respectively, on the third day after incubation. It solubilised 42.3, 66.3 and 74.1 mu g/ml of tricalcium phosphate at 4, 15 and 28 degrees C respectively after seven days of incubation. The strain also possessed HCN and siderophore production abilities at 4 degrees C. It exhibited inhibitory activity against several phytopathogenic fungi in three different bioassays. The maximum relative growth inhibition was recorded against Sclerotium rolfsii and Rhizoctonia solani (100%), followed by Pythium sp. (73.1%) and Fusarium oxysporum (19.7%;, in volatile compound assays. Seed bacterization with the isolate enhanced the germination of wheat seedlings grown at 18 +/- 1 degrees C by 20.3%. Bacterized seeds also recorded 30.2 and 27.5% higher root and shoot length respectively, compared to uninoculated controls.