Genetically modified plants will probably play a role in any attempt to claim harsh alien soil for human use. In fact, they will apparently play a role in terrestrial agriculture. So why not extraterrestrial agriculture? Will we create 'designer life' that can make use of, say, martian soil, air, and sunlight? Might make colonization a bit easier.

Most of the article appears below.

Tomatoes Tolerate Salt

Gene Makes Tomatoes Tolerate Salt
John Travis

The birthplace of agriculture, the Mideast's Fertile Crescent, became largely a desert long ago, and salt in the soil had a lot to do with it. Today, according to some estimates, salt-laden soil ruins the farming potential of more than one-third of all irrigated lands worldwide. "Every time we water the land, we're depositing minute quantities of salt. It catches up with us," notes Eduardo Blumwald of the University of California, Davis.

Blumwald and a colleague have now made a dramatic advance in combating this agricultural nightmare (SN: 11/10/84, p. 298; 11/17/84, p. 314). They genetically modified a traditional crop plant, the tomato, so that it can thrive in salty water. Besides providing farmers with a cash crop for salted lands, such plants may also pull salt out of soils, enabling other crops to thrive again.

"It's a remarkable feat," says UC-Davis' Emanuel Epstein, who decades ago proposed endowing commercial crops with salt tolerance....

Blumwald has now duplicated his Arabidopsis work in the tomato. In the August Nature Biotechnology, he and Hong-Xia Zhang of the University of Toronto report that their altered plant can grow hydroponically in solutions with sodium chloride concentrations of 200 millimolar (mM). Most crops start dying off at 50 mM salt; seawater contains 530 mM.

The altered tomato plant draws salt from the soil mostly into its leaves, not into its fruit. According to Blumwald's unofficial and admittedly biased testing, the tomatoes "taste great...."

Blumwald remains confident. He already has introduced the salt-tolerance gene into canola, the seeds of which provide a valuable oil.

He hopes eventually to further improve plants' salt tolerance to the point where they could be irrigated with seawater. Says Blumwald: "It's not a dream anymore. It's a real possibility."