Characterization of plant growth promoting rhizobia from root nodule of Mimosa pudica grown in Assam, India

Abstract

Aim Rhizobia are diverse group of soil microorganisms that can form nodule in the roots of leguminous plants and fixes atmospheric nitrogen. In the present study, an attempt was made to characterize the plant growth promoting rhizobia from rootnodules of Mimosa pudica grown in Assam. Methodology The bacterial isolates were investigated for their phenotypic features. Plant growth promoting abilities of the isolates were determined by conducting different tests. Genotypic characterization of the isolates was carried out by 16S rDNAPCR-RFLP and 16SrDNAgene sequencing. Symbiotic efficiency of the isolates was determined by nodulation test. Results The isolates showed similarity in colony morphology, shape and Gram staining, but shaved variation in biochemical features. Most of the isolates produced indole acetic acid, ammonia and solubilized inorganic phosphate. Dendrogram based on PCR- RFLP analysis of 16S rONA gene revealed significant diversity among the isolates. Phylogenetic analysis of the isolates, based on 16S rONA gene sequences, revealed that SMP2, HMP1 and DMP2 isolates were closely related to Burkholderia mimosarum PAS44, while KMP1 was closely related to Me so rh izobi um loti MA FF303099. Interpretation The present study revealed that bacterial strains from Burkholderia genera were the major symbionts of Mimosa pudca grown in Assam. The isolates obtained in the present study possesed plant growth promoting abilities and could be used as a potent inoculants in future.