Isolation screening and molecular characterization of zinc solubilizing bacteria and their effect on the growth of wheat (Triticum aestivum)

Abstract

Wheat (Triticum aestivum) is a major cereal crop grown worldwide. Most of the world population depends on wheat for their nutrient requirement. Zinc (Zn) is one of the most crucial elements required for the development of wheat plant. It is one of the micronutrients required in many biochemical cycles. It has been found that the concentration of Zn is below the required level in the soil and hence it remains deficient in the crops. To ameliorate the deficit, chemical fertilizers are added in the soil, where as biofertilizers are preferred over chemicals in sustainable agriculture. The paper describes the isolation, screening and molecular characterization of the zinc solubilizing bacteria (ZSB) to improve plant growth. A total of 100 soil samples were collected from the rhizospheric soil of wheat plants. ZSB were isolated by dilution plating on Bunt and Rovira media. The 50 isolates were selected and screened for their Zn solubilization. The zinc tolerance of all the isolates varied from 0.5% to 2% of insoluble Zn. Based on the Zn tolerance ability, 15 bacterial isolates were screened for Phosphate solubilization and further analyzed for the synthesis of IAA, NH3, siderophore production and chitinase activity. The three isolates were selected on the basis of the plant growth promoting characteristics for molecular characterization and were found to be homologous to Bacillus cereus, Pseudomonas aeruginosa and Bacillus tropicus. This study documented the establishment and survival of ZSB in the wheat rhizosphere and enhanced plant productivity, thus indicating the potential of isolates as commercial biofertilizers.