Genetically Engineered Tomato Plant Grows In Salty Water

As the first truly salt-tolerant crop, these tomatoes offer hope that other crops can also be genetically modified for planting in many areas of the world that have salty irrigation water and salt-damaged soils.

"Since environmental stress due to salinity is one of the most serious factors limiting the productivity of crops, this innovation will have significant implications for agriculture worldwide," said Eduardo Blumwald, who led the research team that discovered the salt-tolerance gene. The research, much of which was done at the University of Toronto, continues in the UC Davis Department of Pomology.

The most recent findings by Blumwald and Hong-Xia Zhang, a postdoctoral fellow at the University of Toronto, will be published July 31 in the August issue of the journal Nature Biotechnology.

Worldwide an estimated 24.7 million acres (10 million hectares) -- about one-fifth the area of California -- of once agriculturally productive land are being lost annually because of irrigation-induced salinity, according to the U.S. Department of Agriculture. Crop production is limited by salinity on 40 percent of the world's irrigated land and on 25 percent of irrigated land in the United States.

This progressive loss of farmable land is on a collision course with the expanding global population, which over the next 30 years is expected to require an increase in food production of 20 percent in developed countries and 60 percent in developing nations.

Although scientists have been trying to develop salt-tolerant crop varieties using selective breeding techniques throughout the past century, none of those efforts has proven successful.

Crop irrigation is an age-old practice that allows farmers to be less dependent on seasonal rainfall and the uncertainties of the weather. However, irrigation also increases the salinity of soils and water by depositing in the fields soluble salts such as sodium, calcium, magnesium, potassium, sulfate and chloride that the water has picked up from the soils and rocks it has passed through. Eventually these salts accumulate in the irrigated soils at levels that decrease the vigor and productivity of the crops grown there.

Salty irrigation water wreaks havoc on most plants by upsetting their ability to take in water through their root cells. In fact, if salt concentrations in the soil are very high, flow of water into the plant is actually reve