Each year, nearly 25 million acres of once-farmable land are lost to salty irrigation water. The salts deposited in the fields disrupt a plant's ability to soak up water through the roots, lowering productivity and sometimes even dehydrating the plant entirely. Scientists have tried for decades to develop salt-tolerant crops through selective breeding but to no avail. Now findings described in the August issue of the journal Nature Biotechnology are offering the first seeds of hope. According to the report, researchers have genetically engineered tomato plants that flourish in salty water.

Earlier research had identified a plant protein that isolates salt, stowing it in intracellular compartments where it cannot upset the plant's normal biochemical routine. Building on that work, Eduardo Blumwald of the University of California at Davis and University of Toronto postdoctoral fellow Hong-Xia Zhang genetically manipulated tomato plants to manufacture more of this so-called transport protein. The resulting plants grow and produce fruit even when irrigated with water that's 50 times saltier than normal¿more than a third as salty as seawater.

The researchers grew the salt-tolerant plants in greenhouses, but Blumwald hopes to conduct field trials in salt-damaged soils in the future. If all goes as planned, he notes, scientists could develop commercially useful versions of these transgenic tomato plants within three years.