in what could make growing paddy on vast, virgin seashores a reality, scientists at Kolkata's Bose Institute have discovered a gene responsible for salt tolerance in mangroves and mimicked its mechanism to produce a wonder rice variety that can survive salinity.

Arun Lahiri Majumder and his team from the institute's Centre for Plant and Molecular and Cellular Genetics department, have successfully grown bounty crops of saline-resistant rice and mustard under greenhouse conditions by cloning the gene from a wild rice variety that is found in the Sunderbans mangrove delta.

The scientists have submitted the gene to the international gene bank. They have also applied for a patent on the gene in the us and in Europe. Their patent applications are in the final stage.

The discovery followed an extensive study conducted to understand the biological processes of mangrove vegetation, which can withstand extraordinarily high levels of salinity. The salt-tolerant gene expresses an enzyme that catalyses a reaction to trigger production of inositol, one of the several chemicals that contribute to salt tolerance.

In normal plants, the enzyme inositol synthatase stops functioning in saline environments and the plants wither due to a salt shock, says Lahiri Majumder. But mangrove plants produce enough inositol for them to survive in saline water.

The team found this enzyme in the Porteresia coarcata rice variety from the Sunderbans, obtained a full-length clone dna for the inositol synthatase gene from its leaf and sequenced it. The scientists conducted a series of experiments, following which they found that the recombinant gene was ideal for incorporating into rice varieties as it retained its salt-tolerant character.

The scientists are breeding the transgenics under contained trial conditions on 18 acres (about 7 hectares) at the Centre for Agricultural Biotechnology in Madhyamgram near Kolkata. After the fourth generation of transgenics, they will be handed over to the government's department of biotechnology (dbt), which has funded the project. dbt will then carry out large-scale field trials.