Molecular identification and characterizations of rhizobacterial isolates collected from lentil rhizosphere of Indo-gangetic plains.

Abstract

Plant growth promoting rhizobacteria (PGPR) are also known to colonize in the soil rhizosphere and prevent the development of other soil borne pathogens residing in the root surface. These microorganisms play a vital role in growth and development of the plant and also enhances the soil fertility by enriching the soil with different beneficial nutrients. This study was aimed at isolation of different rhizobacteria and their molecular characterization in search of efficient bacterial strains with multiple growth regulating activities. A total 36 bacteria were isolated from lentil root nodule as well as soil from different lentil growing fields with a view to screen/evaluate their plant growth promoting potential. Morphological characterization of isolated rhizobacterial candidates were done by observing the colonies on YEMA and nutrient agar media. Determination of CFU, Congo red test and gram staining tests were done to further screen them according to their morphology. All the isolates were then undergone molecular phylogenetic analysis using the partial sequences of the 16S rDNA. Based upon the Gram staining test, all the isolates were negative in gram reaction except six Bacillus isolates, PSB2 and AB3. Results of Ribosomal Database Project (RDP) and Basic Local Alignment Search Tool for Nucleotide Sequences (BLASTn) from 16S rDNA gene sequences showed that these isolates are genetically diverse. A total of 15 isolates of Rhizobium, 6 isolates of Bacillus, 3 isolates of Pseudomonas, 2 isolates of Phosphate Solubilizing Bacteria, 4 isolates of actinomycetes were identified by molecular sequencing of their 16S rDNA region and comparing them with the other isolates enlisted in the database of NCBI for the similarity percentage, query coverage. The purpose of the present study was to select native rhizosphere bacteria from the lentil nodule and soil of Lentil field and to evaluate their plant growth promoting potential as an alternative of chemical fertilizer for sustainable, environment friendly agriculture and assessment of their phylogenetic characterization.