The rhizobacterial strains recovered from different rhizospheres were characterized and exposed to potassium dichromate and nickel chloride in order to discover metal tolerant bacterial strains with multiple plant growth promoting activities. A total of four metal tolerant bacterial strains belonging to genera Pseudomonas, Bradyrhizobium, Azotobacter, and Bacillus were selected and evaluated for growth promoting potential under heavy metal stress. All strains were though positive for ammonia and siderophore production, but Bacillus showed poor ammonia production at higher concentration of Cr (VI). Furthermore, the metal tolerant and plant growth promoting positive Bradyrhizobium sp. augmented the growth of mungbean grown with varying rates of heavy metals. The present study suggests that the toxic metals indeed had inhibitory impact on survivability of potential microflora but they did not completely abolish their physiological activities even under metal horror conditions. Due to these, the metal tolerant PGPR could be useful as inoculant for enhancing the overall performance of mungbean when grown even under metal enriched soils.
Heavy metals, Metal tolerant PGPR, Plant biomolecules, Vigna radiata
