Why in News:

• Using two indigenous strains of bacterium isolated from arsenic-contaminated field, researchers from CSIR-National Botanical Research Institute (CSIR-NBRI), Lucknow and the University of Lucknow have shown that arsenic can be effectively removed from contaminated soil with the help of microbes.

Details:

• Bacillus flexus and Acinetobacter junii is the bacteria that can promote plant growth.
• Using arsenic-contaminated water for agricultural purposes can lead to increased concentration of arsenic in fruits and grains, proving toxic to humans.
• It is found that the two bacteria under different concentrations of arsenate and arsenite, the toxic forms of heavy metal.
  Arsenic treatment did not stunt or delay the growth of both the bacterial strains.
• B. flexus exhibited resistance to high levels (150 mmol per litre) of arsenate and A. junii to about 70 mmol per litre of arsenite. This is higher than previously reported arsenic tolerant bacteria and so were regarded as hyper-tolerant strains.
• Both the bacteria have a special ars C gene, which aids in arsenic detoxification.
• Both the bacteria were able to solubilise phosphorus. Phosphate solubilising bacteria have been reported to increase phytoavailability of phosphate, thus facilitating plant growth.
• These two bacterial strains were also found to produce siderophores and ACC deaminase enzyme. Siderophore increase the bioavailability of iron and other metal ions in polluted soil environment and ACC deaminase is a well-known plant growth promoting enzyme.
• These bacteria can live symbiotically in the roots of plants in arsenic- contaminated soils and help them uptake the required nutrients without causing toxicity.
• It has the potential to accumulate arsenic within the cells and transform it into less phytotoxic forms, making the strains more proficient candidate for bioremediation.

Background: / National Botanical Research Institute

• The National Botanical Research Institute (NBRI) is a research institute of CSIR in Lucknow. It is engaged in the field of taxonomy and modern biology

CSIR

• CSIR is government’s autonomous research agency, established in 1942.
• CSIR has over 4,500 scientists working across 38 laboratories and employs over 9000 scientific and technical personnel.
• The research bodies under CSIR cover science and technology focus areas ranging from aeronautics, instrumentation, mining, environmental engineering and to oceanography, geophysics, chemicals, drugs, genomics and biotechnology.