Rhizobium Leguminosarum: A Model Arsenic Resistant, Arsenite Oxidizing Bacterium Possessing Plant Growth Promoting Attributes

The threat of arsenic (As) pollution has become serious and leading to opt of low-cost microbial remediation strategies.Some bacteria have the ability to resist As. A group of rhizosphere bacteria have the ability to absorb arsenic. So these bacteria may be a good candidate for arsenic bioremediation from contaminated environment. Our present study of identifying suitable rhizobacterial strains led to the isolation of As-tolerant strains from arsenic pollutedrhizospheric soils of lentil in West Bengal, India.The isolated rhizobacterial strain LAR-7 had a high MIC (minimum inhibitory concentration) towards arsenate (260 mM) and arsenite (27.5 mM) and transformed 39% of arenite to arsenate under laboratory condition. Further, the strain LAR-7 had enormous plant growth-promoting characteristics (PGP), as categorized by efficient ability to solubilize phosphate, siderophore production, production of indole acetic acid-like molecules, ACC deaminase production, and nodule formation under As stressed condition. Based on 16S rRNA homology the LAR-7 was identified as Rhizobium leguminosarum andemerged as the most potent strain for As decontamination and plant growth promoter under the stress environment of As.