European and American groups announced simultaneously yesterday that they have put genes from bacteria into petunias and other plants and have gotten the genes to continue functioning normally.
Such a feat has been accomplished in bacteria, and some other small creatures such as the fruit fly, but never yet in plants.
The development is a milestone in scientists' attempt to use gene engineering to alter the basic makeup of plants. It is also a crucial step toward the developing more practical uses for plant genetics such as the creation of self-fertilizing or drought-resistant plants.
"This is the first big step in something we have been working toward in many laboratories around the country for a long time. It is a fundamental step forward, the first time we have inserted a gene into a plant cell and gotten it expressed to function ," said Ernest G. Jaworski, director of Monsanto's Molecular Biology Group.
"It is a first step, but still a long way from what we are all after--that is, transforming plants in a genetically useful manner," Jaworski said.
The European group, led by Josef Schell, a plant geneticist from the University of Ghent in Belgium, and three scientists at Monsanto--Robert Horsch, Robert T. Fraley, and Stephen G. Rogers--announced simultaneously but in separate papers that they had succeeded in transferring a bacterial gene into a variety of plants, including petunias, sunflowers, tobacco and carrots.
The method that both groups used was nearly identical: they piggybacked the foreign genes into plants. There is a bacterium in nature called Agrobacterium tumefaciens which can insert tumor-causing genes into plants.
But the researchers silenced or removed the tumor-causing genes of the bacterium, while keeping the all-important "carrier" genes which had allowed the tumor material to be inserted into the plant without being rejected.
They then attached to this "carrier" or "vector" gene the one they wished to be transferred into the plant. The transplanted genes were taken up by the plant and continued to operate. In this case, the researchers transferred into the plants, for technical reasons, a gene that confers resistance to the antibiotic kanamycin.
Plants do not normally have such antibiotic-resistant genes. The plants so far tested have been able to survive doses of antibiotics that would normally kill them. The plants have not yet grown to full-size, normal adult plants, but they are up to eight times more resistant to kanamycin than normal plants of their type.
Scientists have for some years wanted to use the Agrobacterium's power to inject genes. What is now necessary is to grow a crop of normal plants with the working foreign gene from the experiment.
Then, said Jaworski, scientists could begin looking for useful genes to transfer into plants. For example, genes that help plants resist herbicides or resist disease might be candidates for insertion into crop plants.
Papers announcing the results were presented at the 15th Miami Winter Symposium on biology.