Developments in Brief : Gene Therapy Really Smoking for Tobacco

Scientists have for the first time inserted a gene from a virus into a plant and demonstrated that the altered plant is subsequently resistant to viral infections.

If their results can be transferred to field crops, the economic potential is large. Each year, the tobacco mosaic virus, for example, does $50 million in damage to tomatoes, destroying about 5% of the crop. The wheat streak mosaic virus causes about $95 million in damage to wheat.

Scientists have previously shown that infection of plants with a benign virus can reduce or prevent subsequent infection by a disease-causing virus, but that is an expensive process.

Now, biologists Roger Beachey of Washington University and Robert Fraley of the Monsanto Co. report in the journal Science that they and their colleagues have used genetic engineering techniques to insert a gene from the tobacco mosaic virus into cells from tobacco and tomato plants. Intact plants grown from the altered cells produced the viral protein and passed the gene along to about 75% of their progeny.

When seedlings from the plants were exposed to low concentrations of the virus in a greenhouse, about 60% of the seedlings did not become infected and infection of the rest was delayed by as long as 10 days.

Beachy said in a telephone interview that “the level of resistance in the plants is quite good and it should provide protection in the field.” The investigators are not ready to conduct field experiments yet, however, “because we simply haven’t accumulated the paper work,” he said.

Beachy predicted that they would apply to the Department of Agriculture for permission to test the technique in the field within a year.