Isolation, molecular characterization and growth-promotion activities of a cold tolerant bacterium Pseudomonas sp NARs9 (MTCC9002) from the Indian Himalayas

A bacterium that grows and expresses plant growth promotion traits at 4 degrees C was isolated from the rhizospheric soil of Amaranth, cultivated at a high altitude location in the North Western Indian Himalayas. The isolate was Gram negative and the cells appeared its rods (2.91 x 0.71 mu m in size). It grew at temperatures ranging from 4 to 30 degrees C, with a growth optimum at 28 degrees C. It exhibited tolerance to a wide pH range (5-10; optimum 8.0) and salt concentrations up to 6% (wt/vol). Although it was sensitive to Rifampicin (R 20 mu g ml(-1)). Gentamicin (G 3 mu g ml(-1)), and Streptomycin (S 5 mu g ml(-1)), it showed resistance to higher concentrations of Ampicillin (A 500 mu g ml(-1)), Penicillin (P 300 mu g ml(-1)), Polymixin B sulphate (Pb 100 mu g ml(-1)) and Chloramphenicol (C 200 mu g ml(-1)). The 16S rRNA sequence analysis revealed maximum identity with Pseudomonas lurida. The bacterium produced Indole Acetic Acid (IAA) and solubilizes phosphate at 4, 15 and 28 degrees C. It also retained its ability to produce rhamnolipids and siderophores at 15 degrees C. Seed bacterization with the isolate enhanced the germination, shoot and root lengths of thirty-day-old wheat seedlings by 19.2. 30.0 & 22.9% respectively, as compared to the un-inoculated controls.