New Fields For Food

Mary-Dell Chilton's DNA discoveries launched the field of genetically modifying plants to ward off pests, use less water, and improve yields. Supporters say it could help feed the world. Opponents say it's not safe, threatening the environment and people in ways that may not be known yet. By discovering the mechanism of DNA transfer, Chilton bestowed that power to humans.

RESEARCH TRIANGLE PARK - Ask almost any scientist working on food, nutrition and agriculture issues what the ultimate goal of their research is, and chances are you’ll hear something like:

“I want to help feed the world’s hungry!”

Last year, one of those researchers, Mary-Dell Chilton, who works at Syngenta in Research Triangle Park, was awarded the World Food Prize for her discovery in the field of genetically modified crops.

In the 1980s, Chilton and her team became pioneers in the field with the discovery that genetically modified seeds will carry DNA that has been altered to express a favorable trait, such as the resistance to a pest or a fungus.

That technology would be enough for most people to have discovered in one lifetime. But at age 74, Chilton is still hard at work. And she is searching for new discoveries in a lab that bears her name. Oh yes, the Syngenta building where the lab is located is also named after Chilton.

“It’s curiosity-driven, I want to find out why things work,” says Dr. Chilton. “We use this kind of technology to find out what makes a plant cell work, what genes do they express, what do they do when we do this. This technology is not just a tool for genetic engineering, it’s a tool for the plant biologist to find out how things work.”

That drive to understand how things work led to groundbreaking research on how a plant bacterium can be used as a tool to insert genes from other organisms into plant cells, which could then produce crop varieties with new traits. Chilton was leading a group of researchers at the University of Washington. They harnessed the gene-transfer mechanism of the bacterium agrobacterium.

“So when we first discovered that agrobacterium is putting novel DNA into plant cells and somehow it was managing to stay there and replicate, I didn’t believe it,” Dr.Chilton says, laughing. It turns out the discovery was made while trying to prove it didn’t actually happen.

“In fact, I set out to prove that it wasn’t true, and in trying to prove it wasn’t true, I found it was happening,” she adds.

And that led to the production of the first transgenic plant. It also helped to create the field of genetic engineering of plants. Chilton won the World Food Prize in 2013 for her work. Now, 30 years after the discovery, dozens of companies, including Syngenta, are following in her footsteps. They believe genetic engineering can protect plants from the environment, including pests and disease, as well as increase the amount of a crop that farmers can produce.

A good example of what Chilton’s groundbreaking work has led to is found in labs down the hall from where she continues her research. Dr. Eric Chen is raising corn root worms in a specially designed bug nursery. He and his colleagues have genetically modified corn plants with a trait that will kill the corn root worm. An infestation of this tiny bug can devastate hundreds of acres of corn.

“We call it a trait gene,” says Dr. Chen. “It’s a piece of the gene, or DNA, that we engineered in the lab and identified the activity that will kill root worm. We put it into the plant and into the plant genome. So when the farmer buys the seed, the trait gene is already in it, so the farmer just needs to grow the seed. It’s season-long protection.”

That’s right, by changing the plant’s DNA, researchers have created corn that will express a protein in every cell of the corn plant that will kill a root worm soon after it takes a few nibbles of the plant. That effectively stops an infestation before it gets out of control. 

Hope Hart, who works on the project with Dr. Chen, shows off a chart with a list of proteins. They are color coded and look very similar to the service bars on a military dress uniform.

“So this is the protein, this is the protein recognition site and these are four amino acids that proteins in the root worm gut can recognize,” says Dr. Hart. “We clip the protein and then once the worm eats the corn that contains the proteins, the amino acids in the corn combine with those in root worm gut. When it activates, it forms pores or holes in the gut and kills the root worm.”

Hart says her work helps farmers because using genetically modified crops is a more precise and cost effective way to deal with pests than spraying fields with chemicals. It also lasts all season. 

“If a farmer buys the seeds up front, then has good, consistent protection all season,” says Dr. Hart. “They don’t have to worry about chemicals washing away or getting diffused in the soil because the protection is inside the plant. Essentially, this offers another option for farmers. They can spray if they want or they have a GM solution.”

It takes almost 15 years from when a product is first conceived to when it goes on sale. And almost half of that is spent in safety testing. Researchers need to know if a genetically modified product is is safe to eat and if it is safe for the environment.

Syngenta tests its potential new genetically modified seeds in a high tech greenhouse in Research Triangle Park. It’s one of the largest greenhouse facilities in the world. There are 30 climate-controlled growth areas, so the environment in Kansas can be simulated in one room with Africa in the next.

Throughout that time, scientists take tissue samples from the roots, stalk, and ears to make sure the gene is expressed at the right time, at the right place and in the right level of expression. If studies reveal the plants grown in the greenhouse show a single, intact copy of DNA, meaning the genetic transfer was successful, the plant is moved to field testing, to see if it is performing the way it should.

“The field testing is just as intense as in the greenhouse because we’ll do basic characterization studies so we completely understand what went in and where it went in," says Kevin Leiner, Syngenta Team Leader, Traits Safety Assessment. “We’ll do studies to show does it grow the same as conventional varieties of the same plant, does it have the same composition, in terms of fats, carbohydrates, lipids, amino acids, etc."

Researchers want to understand how the genetically modified plant compares with the conventional variety of the crop, and that includes similarities and differences.

Every phase of the plant’s life cycle, the part it plays in the environment and its potential use, is studied.

But despite the safety assurances, genetically modified crops have become a lightening rod for those concerned about food safety and environmental issues. 

“When we make decisions about new products, we often think safety and benefits and those are really the only two parameters that should matter,” says Jennifer Kuzma, a professor in the School of Public and International Affairs at North Carolina State University. “But then we take a step back and think safety and safety is based on science. However, safety is based on more than that.”

And Kuzma believes that’s one of the reasons why genetic engineering is so controversial. It turns out safety is not only based on science. It is based on shared notion of where we draw the line and what’s safe to me may not be safe to you. In addition, she says where our tolerance as a society for these products is, is based on risk, trust, our cultural world-view, and other factors, including gender and race.

The debate surrounding genetically modified crops prompted NC State to create a program in genetic engineering and society. Researchers will examine the cultural, policy and economic aspects of genetically modified organisms. More than 17 million farmers around the world grow genetically enhanced crops, primarily in the United States, South America and Asia. But much of Europe and Asia have blocked their use.

“People have seen these technologies come and go and here’s another one coming along and no one is quite sure what to make of it,” says Dr. Fred Gould, a professor of Entomology and Co-Director of the Genetic Engineering and Society Program. “And not only that, but this has two ingredients that make people nervous; one, it’s their food, it’s what they eat, and two, it's genetics, and that has a long history of hot buttons issues with people.”

“Genetically modified engineering seems to be falling through the cracks," says Matthew Morse Booker, a member of the study group and an Associate Professor of History at NC State. “Either it's completely prohibited, as it is with certain ones, or it is completely unregulated and that’s the great fear. So, there’s this interesting moment where folks on all sides of the discussion are calling for regulatory reform.” 

Amidst all of the debate, Dr. Mary-Dell Chilton continues her work and focuses on the potential of her discovery to feed the world. Her new goal is to figure out the best way to direct a selected genetic trait to a specific place in the DNA sequence of a plant.

“My task is often working with the biggest molecules,” Chilton says modestly. “It turns out I’m good at that, better than most people. I have a lot of experience.”


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