[BEIJING] Researchers in China and the United States have identified a rice gene linked to salt tolerance, raising hopes of improving the ability of Asia's most important crop to grow in saline soils.

This discovery could have tremendous significance for China's food security because approximately eight per cent of its rice fields have high levels of salt, says lead researcher Lin Hongxuan of the Shanghai Institute for Biological Sciences.

In 2001, another group of Chinese researchers developed genetically modified salt-tolerant rice, which is currently undergoing field trials.

But Lin points out that the rice developed by those researchers contains genes from other species. But the gene Lin's group identified — SKC1 — occurs naturally in a variety of Japanese rice called Nona Bokra.

Having a naturally occurring gene for salt tolerance means it should be possible for researchers to develop new salt-tolerant rice varieties using either traditional breeding or genetic engineering techniques.

The SKC1 gene controls the amount of sodium — a component of salt — that builds up in rice plants as they grow. Too much sodium is detrimental to plant growth.

Lin's team used genetic engineering methods to insert the gene into a rice variety with low salt tolerance. The sodium concentration in the modified plants fell by 25-30 per cent.

"Meanwhile, SKC1 improved the concentration of the mineral potassium by 20 per cent, which is beneficial for rice growth," Lin told SciDev.Net.

"But more work, such as testing how SKC1 interacts with other genes, must be done before this gene can be used to develop a new salt-tolerant rice variety," Lin adds.

Lin's team, from the Shanghai Institute for Biological Sciences, the Chinese Academy of Sciences and the US-based University of California at Berkeley, published their findings online in Nature Genetics, 11 September. The paper will also appear in October's print edition of the journal.

Link to abstract of paper in Nature Genetics

Reference: Nature Genetics doi:10.1038/ng1643