Influence of bacterial strains on Oryza sativa grown under arsenic tainted soil: Accumulation and detoxification response.

The present study was conducted to study the role of bacterial inoculants in growth, accumulation and tolerance responses in rice grown in arsenic (As) contaminated soil. Results revealed that out of five isolated bacterial strains, strain BBAU/MMM1 (Babasaheb Bhimrao Ambedkar University/Mari Matamandir) exhibited resistant to As(III) to the level of 400 μM As(III) in comparison to other strain which showed toxicity. The isolated strain BBAU/MMM1 1was characterized as gram negative, rod shape, showed positive test nitrate, citrate, catalase and phosphate solubilization with high production of IAA and siderophore. Arsenic treated rice seedlings supplemented with bacterial inoculants BBAU/MMM1 showed increased growth characteristics viz., root length (35.41%), shoot length (32.8%) and fresh weight (30.31%) in comparison to rice treated with As(III) only. In addition, reduced lipid peroxidation and induces cysteine, GSH (reduced glutathione), GSSG (Oxidized glutathione) and antioxidant enzymatic activities were also observed in bacterial supplemented rice seedlings. Further, reduced metal accumulation in root (1351.46-968.67 μg g-1fw), shoot (488.01-378.02 μg g-1fw) and reduced translocation factor (0.583-0.390) in As(III) treated rice seedlings inoculated with bacterial strains clearly reflect protective response of bacterial strain against As toxicity. Thus, isolated bacterial strain could be used as bioremediator as well as growth inducer in paddy field contaminated with arsenic.