(News) Gene flow, confinement discussed at symposium

New Haven, Conn. – Genetically modified grass, which many believe could become a major source of golf course turf, was the topic of a symposium, “Gene Confinement for Genetically Modified Grasses,” at Yale University.

Albert Kausch, PhD., says the need for gene confinement in transgenic turfgrass is important.

Government, university and private-sector researchers from throughout the country discussed the controversial issues about the testing and production of genetically engineered grasses and how to avoid their spread to areas where they’re not wanted. Specifically, the concept of gene confinement and gene flow for genetically modified grasses and mechanisms for gene confinement were discussed.

“This is a major issue that must be resolved,” says Joe Duich, Ph.D., professor emeritus from Penn State University. “I hope it will be resolved on a technological rather than political basis.”

Genetic restriction
Harry Collins, Ph.D., vice president of technology transfer at Delta and Pine Land Co., is responsible for intellectual-property issues and is working with Syngenta on an insect-resistance trait. Collins discussed the politics of genetic use restriction technologies, which is defined as methods that regulate gene expression. GURTs can be seen as a mechanism that occurs naturally in any organism, not as a domestication of the regulation of gene expression. Plant breeders have, until now, focused their activity on the introduction and recombination of genes. GURTs will allow them to work on the expression or nonexpression of genes at any stage of crop development or generation. Some potential applications of GURTs could be:

• Increased production of specific molecules;
• Regulation of the expression of resistance genes so that resistance is expressed only when necessary;
• Preventing the spread of unwanted plants created by cross-pollination between genetically modified plants and nongenetically modified ones; and
• Improved protection of intellectual property rights.

“What we’re talking about might be academic, but we feel testing is needed,” says Collins, noting some groups are trying to place a moratorium on GURT testing.

At an international meeting about the subject in Montreal, Collins says a report included many negatives and few positives about GURTs. Organizers recommended, in view of lack of data, GURTs not be tested for commercial use. The movement for a moratorium was stopped later at the Subsidiary Body on Scientific Technical and Technological Advice meeting in Bangkok, he says.
“My point is to alert people that if companies don’t get involved, people who want to ban GURTs will have their way,” Collins says. “Everyone needs to be aware of what’s happening.”

Seed movement
Virgil Meier, Ph.D., is a biotechnologist with the Risk Assessment Group of the United States Department of Agriculture, Animal Plant Health Inspection Service, Biotechnology Regulatory Service. Before working for the USDA, he was manager of turfgrass variety development and seed research activities with The Scotts Co. During Meier’s discussion about the biology of grasses related to gene flow, he says perennial turfgrasses used on golf courses are of particular interest from a biotechnology perspective. They include bentgrass, bluegrass, fescues, ryegrass, Bermudagrass, zoysiagrass, St. Augustinegrass, buffalograss, bahiagrass and centipedegrass. Gene flow and movement of these grasses take place through pollen, seed or vegetatively, Meier says.

Most grasses are pollinated, and pollen typically survives one to three hours, but can travel a significant distance during that time. Grass also can move vegetatively via wind, water, animals, natural growth, soil, equipment and trucks.

But it’s gene flow through seed that concerns Meier most. Grass seed generally is tiny, which makes it mobile. Creeping bentgrass, for instance, has 6.1 million seeds per pound compared to wheat, which has 11,360 seeds per pound. Seed movement is affected in natural ways by wind, water, soil and animals. Movement also is caused by seeding and harvesting equipment, trucks and airplanes.

“Basically there’s no limit to how far seed can travel,” Meier says. “And dry seed can survive 10 years. Seeds are one of the major concerns I have in terms of gene flow.”

Meier says removing flowers could confine pollen movement, preventing flower formation, bagging flowers, encouraging male sterility and isolation. Seed movement can be confined by removing flowers, preventing flower formation, bagging flowers, using dedicated equipment, equipment cleaning, test-location selection, border-area establishment, proper seed containers and storage.

Bentgrass
Lidia Watrud, Ph.D., a principal investigator for the U.S. Environmental Protection Agency in Corvallis, Ore., leads research about ecological effects of gene flow from bioengineered crops. Watrud focused on pollen-mediated gene flow in creeping bentgrass.

Bentgrass is a highly outcrossing, wind-pollinated turfgrass variety that reproduces sexually and asexually. Studies on test plots in Oregon of Roundup Ready Creeping Bentgrass, a genetically engineered bentgrass resistant to the herbicide Roundup, found gene transfer in resident (noncrop) and sentinel plants. Of the sentinel plants, 54 percent showed signs of RRCB genes.

A lesson learned from the trial was that exposure can take place to a viable genetically-modified pollen over a regional area from one of the first perennial genetically modified crops, Watrud says.

Among the potential concerns regarding genetically modified turfgrasses in agriculture is contamination of neighboring farms by genetically modified pollen or seed, which might require alternative herbicides and new label uses to control, Watrud says. There also are potential concerns along waterways, on public/private lands and on golf courses.

“All we have done is measured exposure, not the effects,” says Watrud, noting the next step is ongoing monitoring and repeating the Oregon test.

Seed scatter
Carol Mallory-Smith, Ph.D., a professor of weed science at Oregon State University and president of the Weed Science Society of America, has researched gene flow from transgenic creeping bentgrass and discussed the contribution of seed scatter to gene flow in perennial grasses.

Seed scatter is the loss of seed at any time, from production through final end use. It occurs through natural dispersion, seed-production practices and a combination of various factors.

Perennial grass-seed production requires seeding equipment, application equipment, harvesting equipment, trucks, seed-cleaning equipment and seed distribution. Seed scatter from any of these steps isn’t preventable, although it can be controlled, Mallory-Smith says. Seed scatter also isn’t preventable in the various uses of turfgrass, including golf.

With regard to 400 test acres of RRCB planted in Oregon in 2002, Mallory-Smith says plants testing positive for Roundup resistance were found widely distributed in 2004, the year after a major wind. Most of the resistant plants are believed to be the result of seed scatter, with positive hosts found a mile or more away. It’s yet to be determined what the impact will be.

Even with safeguards in place, researchers learned seed couldn’t be contained. Natural dispersal, coupled with production practices, led to increased seed dispersal. An effective mitigation plan must be in place and control measures need to be developed for all test sites.

“The scatter of creeping bentgrass seed isn’t an ecological disaster nor will it create a major problem,” Mallory-Smith says. “We have learned some important lessons. Genetically altered grasses with drought, salt and disease tolerance that give an economic fitness advantage could have more of an impact. Seed will move. Pollen will move. But if the final answer is, ‘we cannot tolerate that,’ then we can’t do these studies or release these crops.”

Concerns
The next question is, “Does gene flow matter?” and if so, “How can we confine it?” according to Albert Kausch, Ph.D., professor in the department of cell and molecular biology at the University of Rhode Island and one of the symposium chairs. The need for gene confinement in transgenic turfgrass is important because of environmental concerns, public perception and commercial trespass seed inadvertently making its way from one country to another, a potentially major problem, Kausch says. GCN