Indian team decodes TB bacteria genome

Indian scientists have decoded the genetic makeup of a friendly bacterium, which, incidentally, is the progenitor of the harmful tuberculosis and leprosy bacteria worldwide.

This is the first time that an Indian team has decoded the complete genome of a bacterium without the support of foreign scientists.

The decoding of the genome of the soil-inhabiting and friendly Mycobacterium indicus pranii (MIP) will give scientists an insight into the evolutionary history of the bacteria responsible for tuberculosis and leprosy. It will also tell the genetic story of how a harmless bacterial species like MIP underwent changes over a period to give rise to the most challenging health problem in the form of TB.

The decoding of the genome is crucial in evolving effective control measures against mycobacterial infections, including leprosy and TB.

Scientists from the University of Delhi South Campus, the University of Hyderabad, the Indian Institute of Technology, Delhi, and the National Institute of Plant Genome Research were involved in the decoding of the MIP genome.

Eminent scientist Dr Syed E. Hasnain, who is not associated with IIT, Delhi, led the research team. The other team members were Vikram Saini, Saurabh Raghuvanshi, Jite-ndra P. Khurana, Niyaz Ah-med and Akhilesh K. Tyagi.

“The evolutionary and genomic mechanisms responsible for turning the soil-derived saprophytic mycobacteria into lethal intracellular pathogens is a critical step towards the development of strategies for the control of mycobacterial diseases,” said Dr Hasnain, adding that MIP is of specific interest because of its unique immunological and evolutionary significance.

In terms of evolution, MIP is the progenitor of opportunistic pathogens, belonging to M avium complex, and is endowed with features that place it between saprophytic (feeding on decaying material) and pathogenic (disease-causing) species. The MIP has been used in the treatment of leprosy, which India has successfully controlled. However, the fight against TB is still on as it is increasingly becoming resistant to known drugs.

“We show, for the first time for Mycobacterium, that MIP genome has mosaic architecture. These gene acquisitions have led to the enrichment of selected gene families, critical to MIP physiology,” he said.

The genome of the MIP is 5.6 Mb in size and is shaped by a large number of lateral gene acquisitions.
Mycobacterium indicus pranii has been named after India (indicus) and senior scientist Dr Gursaran Pran Talwar (pranii).

Courtesy: Deccan Chronicle