Phylogenetic identification of nitrogen-fixing bacteria isolated from the rhizosphere of asparagus plants using 16s rRNA and the effect of zinc on isolated strains

Introduction: Considering the role of microorganisms in nitrogen stabilizers for the fertility of the soil and growth and development of plants, application of the chemical fertilizers, zinc sulfate (ZnSo4), as micronutrient index in agriculture is taken into account. Due to the toxic effects of zinc metal, the aim of this research was the isolation and identification of nitrogen stabilizer microorganisms of asparagus rhizosphere and to evaluate toxic effect of zinc metal on the growth of bacteria. Material and Method: In order to isolate microorganisms in nitrogen stabilizer, soil samples were prepared from the asparagus rhizosphere and cultured in medium lacking nitrogen with a temperature of 30 °C for 48 hours. Phylogenetic identification was accomplished using 16s rRNA and MIC of the isolated strain was determined in different concentrations of zinc metal. Findings : From the rhizosphere soil samples a strain of bacterium was isolated and its phylogenetic was determined as Acinetobacter calcoaceticus species using the 16s rRNA. The MIC of the species was evaluated at the 52.32 ppm concentration of zinc metal. Discussion & Conclusion: One of the rhizosphere nitrogen stabilizer strains in the asparagus plant is Acinetobacter calcoaceticus bacterium. Elevation of zinc metal causes damage to the microorganism and the maximum allowable amount of zinc metal in this study, was determined to be less than 52.32 ppm.