Escaped GM grass could spread bad news
An escaped strain of transgenic grass bred for golf courses could wreak
havoc on native grassland species in the northwestern United States, ecologists
The strain, which was growing in a test plot in Oregon and hadn't yet been
approved for use by the US Department of Agriculture (USDA), has now been detected
in the wild, up to 3.8 kilometres outside the test area. While the transgenic
component of the plant might not in itself pose a problem, the hardy strain
could replace many other native grasses if it gains a foothold, ecologists say
Scientists working for the US Environmental Protection Agency (EPA) in Corvallis,
Oregon, have been monitoring the region surrounding the experimental plots where
the plants, called creeping bentgrass (Agrostis stolonifera) were being grown
The EPA team studied areas of grass within almost 5 kilometres of the experimental
plot. As they report in a forthcoming issue of Molecular Ecology, of 55 sites
examined, six contained descendants of the transgenic test plants. The researchers
believe that seeds and pollen from the test site were dispersed by the wind
EPA officials stress that the scale of the problem is not yet known. "It
could persist in the wild, but we wouldn't necessarily expect it to have an
advantage," says Jay Reichman, one of the scientists who tracked down the
grass in the wild. "Its impact remains to be seen."
The USDA has started a full environmental impact assessment of the plant.
It is not clear what advantage, if any, the grass's transgenic status will
give it in the wild. The strain, bred by The Scotts Company, based in Marysville,
Ohio, was engineered to be resistant to the herbicide glyphosate, also known
as Roundup. This means that it would be difficult to eradicate from areas where
other grasses are grown and managed with herbicides.
More pressing is the effect that the grasses might have on other local grass
species, says Tom Stohlgren, an ecologist at the US Geological Survey's National
Institute of Invasive Species Science in Fort Collins, Colorado. Plants of this
type, called 'sod-forming' grasses, can spread rapidly because they can reproduce
sexually, through widely dispersing pollen and seeds, and also asexually, by
forming a dense mat of roots from which more shoots emerge.
Although bentgrass would be unlikely to encounter herbicide in the wild, so
its transgenic status wouldn't necessarily be an issue, it might still plough
down native grasses. "Sod-forming grasses can tend to outcompete other
species," he explains. "It doesn't need to sexually reproduce - it's
like The Blob. It could potentially hit rare species or national parks."
Distances of a few dozen kilometres won't be enough to stop a tenacious grass,
Stohlgren adds. Grasses, unlike food crop plants, are perennial, meaning that
they survive from one year to the next. And their seeds are so fine that they
can easily be transferred from place to place by the wind or by sticking to
animals, people or vehicles.
Oregon's grass-seed industry, which produces some 70% of seed for US gardeners
and groundskeepers, is based in Willamette Valley, about 90 kilometres away
from the test site. If the bentgrass reaches here, it would be very hard to
Grasses have mounted widespread invasions before, Stohlgren says. In 1998,
he showed how Kentucky bluegrass (Poa pratensis) had swept through Wind Cave
National Park in South Dakota, tearing through habitats that previously contained
a diverse range of grasses. Kentucky bluegrass can now be found in every state
in the country.
The rampant spreading ability of bentgrass could also pass on the transgene
for Roundup resistance to other grass species through hybridization, Stohlgren
adds. "We've broken down the barriers - things happen so fast," he
says. "It's like Darwin on steroids."
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