Borrowed gene helps wild sunflower. (Tougher Weeds?).
Tests of sunflowers show for the first time that a gene from a genetically engineered genetically engineered adjective Recombinant, see there crop gives a wild, weedy relative an edge in life outdoors, say researchers. That extra toughness feeds worries that genes escaping from transgenic crops could create feistier weeds.
Thanks to a gene borrowed from the Bacillus bacillus (bəsĭl`əs), any rod-shaped bacterium or, more particularly, a rod-shaped bacterium of the genus Bacillus. Some bacterium in the genus cause disease, for example B. thuringiensis bacterium, the sunflower variety used in the test makes built-in Bt pesticide. When researchers crossed these souped-up plants with wild sunflowers, the Bt gene passed to some of the offspring, report Allison Snow of Ohio State University Ohio State University, main campus at Columbus; land-grant and state supported; coeducational; chartered 1870, opened 1873 as Ohio Agricultural and Mechanical College, renamed 1878. There are also campuses at Lima, Mansfield, Marion, and Newark. in Columbus and her colleagues.
To mimic the effect of a manipulated gene escaping into the wild, the scientists then crossed the first generation of transgenic hybrids with wild plants. The offspring of this mating performed well outdoors, setting extra seeds and reducing pests, the researchers reported in Tucson last week at the annual meeting of the Ecological Society of America The Ecological Society of America (ESA) is a professional society for ecologists located in the United States. It has about 9,000 members.
The society was formed at a meeting at Columbus Ohio, on December 28,1915, with the aims to:
Earlier research had already shown that genes can readily leak out of crops into wild plants, according to Neal Stewart of the University of Tennessee The University of Tennessee (UT), sometimes called the University of Tennessee at Knoxville (UT Knoxville or UTK), is the flagship institution of the statewide land-grant University of Tennessee public university system in the American state of Tennessee. in Knoxville, who studies canola. "The genes are going to move," he says. "What people haven't done is look at the consequences."
Another investigator of wandering transgenes, Norman Ellstrand of the University of California, Riverside The University of California, Riverside, commonly known as UCR or UC Riverside, is a public research university and one of ten campuses of the University of California system. , agrees that "we know very little about the performance of [transgenic] hybrids in the field." He calls the sunflower work "significant and important."
The specter of escaping transgenes haunts some crops more than others. Corn and soybeans, for example, don't have close relatives near U.S. fields, but the Snow team points out worrisome neighbors for some 20 other crops, including rice, sorghum sorghum, tall, coarse annual (Sorghum vulgare) of the family Gramineae (grass family), somewhat similar in appearance to corn (but having the grain in a panicle rather than an ear) and used for much the same purposes. , canola, strawberries, and turf grasses. The sunflowers look especially prone to gene swapping since botanists consider the crop varieties and a wild weed, Helianthus annuus Helianthus annuus,
n See sunflower.
toxic plant in the family Asteraceae; causes nitrate-nitrite poisoning. Called also summer flower. , to be the same species.
Ellstrand cautions that a transgene transgene
a gene that has been incorporated into the genome of another organism. won't necessarily help a weed. The wild plant may already have enough defenses against pests, for example, or the gene may exact a metabolic cost.
So far, no transgenic sunflowers have hit the U.S. market. Snow and her colleagues worked with an experimental variety and its wild relatives. Following strict containment procedures, the researchers planted their selected second-generation hybrids outdoors.
In a high-pest zone in Nebraska, sunflowers carrying the borrowed Bt gene set 55 percent more seeds than hybrid descendants without the gene did. Even in the less-insect-infested site in Colorado, the transgenic hybrids beat the others by 14 percent in seed setting. Also, the Bt-producing offspring suffered fewer attacks from insects.
In the greenhouse, there was no evidence that the transgenic descendants paid a price for the Bt advantage, even under drought or low-nutrient regimens, say the researchers.
The project shows that the transgene adds an edge, says Ellstrand, but now he asks whether that advantage will boost the weed's invasion power.