Isolation of Heavy Metal-Tolerant PGPR Strains and Amelioration of Chromium Effect in Wheat in Combination with Biochar

In the present study, detection of heavy metals was carried out in a textile industry soil by ICPOES method. Chromium was the most abundant heavy metal in the examined soil samples and its concentration (95-1180 ppm) exceed the EPA limit. Furthermore, six chromium-tolerant bacterial strains were isolated, most of which belong to Bacillus spp. The maximum tolerance limit of strains was 0.5 ppm for K2Cr2O7. Cr-tolerant strains in consortium were used for the inoculation in combination with biochar. The maximum increase in shoot and root length was (22-23.4%), and maximum increase in chlorophyll and SOD was (28-40%). In the similar way, the proline and sugar contents were improved up to 20.5% and 9.6%, respectively. Significant reduction in Cr uptake was recorded in dry biomass of wheat plants where Cr concentration was 0.28 +/- 1.01 mg/kg as compared to control. Hence, according to the findings, PGPR and biochar are an important tool for amelioration of chromium and can be used as inoculums for better plant production.