Screening of bacterial strains for developing effective pesticide-tolerant plant growth-promoting microbial consortia from rhizosphere soils of vegetable fields of eastern Uttar Pradesh, India

Abstract

The current study was intended to isolate and characterize the plant growth-promoting properties and pesticide (chlorpyripfos) tolerance ability of microbial strains for sustainable vegetable productions. Plant growth-promoting microorganism is a group of microbial consortia to improve crop growth and yield by various direct mechanisms, e.g. nitrogen fixation, phosphate solubilization, production of plant growth hormones, ammonia and siderophore, and indirect mechanisms, e.g. production of antibiotic, hydrogen cyanide to help as biocontrolling agent. Totally, 50 microbes were isolated from soils of vegetable field. Out of 50, 14 strains were selected on the basis of morphological, growth biochemically characters (e.g. gram staining, amylase, cellulase, catalase and citrate test) and plant growth-promoting properties. All strains have ability of ammonia production. Out of 14 strains, IESDV2, IESDV3, IESDV4, IESDV11, IESDV12 and IESD28 were found significant increase in production of IAA, ammonia and phosphate solubilization than others. Strains IESDV3 and IESDV11 showed tolerant at 6 μl/ml concentration of chlorpyrifos which is three-time increase concentration of recommended dose (2 μl/ml). Others strains IESDV12, IESDV13 and IESDV28 were also showed resistance or tolerance at different concentrations of pesticide 2, 4, 6 and 20 μl/ml. These strains also showed plant growth-promoting rhizobacteria activities. Therefore, the main result of this study is to screen and identify that three strains (IESDV3, IESDV11, IESDV12 and IESDV28) can be used as effective pesticide-tolerant plant growth-promoting microbial consortia for vegetable production under sustainable agriculture at eastern Uttar Pradesh.