Extraction and evaluation of gibberellic acid from Pseudomonas sp.: Plant growth promoting rhizobacteria

In current investigation thirty isolates of Fluorescent Pseudomonas sp. were isolated from apple and pear rhizosphere and characterization of 30 native fluorescent Pseudomonas strains was done phenotypically (Gram’s staining, oxidase, catalase test, gelatin liquification, denitrification test, gelatin liquification, MR/VP, citrate utilization, indole production) and genotypically (16S rRNA). They were investigated for gibberellins production. The range of the production of gibberellins was found 116.1 -485.8µg/ml. Two isolates viz., An-1-kul and An-13-kul were selected on the basis of higher production of gibberellins. The gibberellins produced by best isolates (An-1-kul and An-13-kul) were extracted and partially purified and characterized by TLC (thin layer chromatography) and estimated via high performance liquid chromatography (HPLC) in liquid culture. Extracted gibberellins gave gray coloured spot with Rf value 0.78 and 0.79 of gibberellins for An-1-kul and An-13-kul respectively. Gibberellins extracted from Pseudomonas sp. were further evaluated for alpha-amylase activity. The range of gibberellins production from fluorescent Pseudomonas isolates An-1-kul and An-13-kul was 485.8μg/ml and 419.2μg/ml culture with a retention time of 2.35 and 2.32 respectively.