Agriculture/Harvest Public Media
Mon February 18, 2013
Science of the Seed Part 1
The vast majority of the corn and soybeans in United States grow from seeds that have been genetically modified. The technology is barely 30 years old and the controversy surrounding it somewhat younger. But how did it even become possible?
First, a note about terminology. Genetic modification, gene transformation and genetic engineering, even biotechnology in an agricultural context, all refer to the same thing: taking a gene from one organism (usually bacteria) and inserting it into another.
The scientists who discovered this technology back in the 1980s weren’t even looking for ways to improve plants. Iowa State University agronomy professor Kan Wang worked was on the laboratory frontline then, working with biochemists studying agrobacteria and plant tumors.
“Their motivation [was] to cure human disease,” she said. “By working on the plant disease, they hoped [they] would get some knowledge, but they completely opened up a different can of worms.”
Scientists discovered that certain agrobacteria could infect a plant, cause a tumor, and then leave the disease behind even after the bacteria was removed. It’s like if you had strep throat — a bacterial infection — but then after your course of antibiotics, the strep is gone but the sore throat remains —forever. Sounds horrible, right? The researchers figured out that the evil bacteria had a particular plasmid that did the dirty deed.
“What happens is a piece of the DNA comes off of this plasmid and it goes through [the] bacteria cell wall and cross[es] through [the] plant cell wall and then gets into [the] plant cell nucleus,” Wang said.
Once inside, it integrates into the plant cell chromosome and permanently transforms the plant’s genetics. This understanding changed the course of the research, Wang said.
“The light bulb switched on and we say, hey, we have a tool!” she said.
The research focus moved away from human cancer. Scientists in both academic and industry labs set about determining how they could harness this tool to move good traits. St. Louis-basedMonsanto emerged early as a leader in biotech. The company demonstrated successful gene transfer in tomato plants in 1987.
“We have scientists that figured out that gene that the bacteria moved? [We] take that gene out and we put a gene into the bacteria that we’d like to have moved, and the bacteria move the gene for us,” said Tom Hoogheen, a tour guide at Monsanto’s Chesterfield Village Research Facility near St. Louis
In a long dimly lit hallway, he pointed to a large flat-screen monitor showing an illustration of the soy bean genome. He said the key is to identify a protein that has a desired effect on a plant and then figure out what gene to transfer to force the plant to produce that protein.
“What if I can find a protein that slows down sap flow in a corn plant? Doesn’t need as much water —drought,” he said. “What if I can find a protein that allows a plant to photosynthesize a new way? So I can spray RoundUp over the top and not kill it?”
RoundUp is Monsanto’s widely used herbicide, which previously farmers had to be careful not to spray on their crop plants, because it would kill everything. But inserting the bacterial gene in the soybean seed made the soyplants resistant to Round Up. Hoogheen noted that the researchers working on RoundUp resistance found the vital gene in bacteria living in the wastewater treatment plant at the place where RoundUp was made.
In 1996, after meeting newly established regulatory requirements, RoundUp Ready soy beans hit the market. So from “a-ha” moment to farmers’ fields took less than 10 years.
And today, genetic engineering is ubiquitous … and controversial. With young technology, there’s only so much data about safety and long-term implications. And now that the technology is out of the lab and in people’s pantries, many people are skeptical of the science and fearful of the implications.
“Some people call it like Frankenseeds,” said Mike Stahr, manager of the Seed Lab at Iowa State University, adding that public perceptions vary by culture. In Europe, GMO products remain more closely regulated than here.
“There’s just more of a concern for some reason in Europe about you’re messing with the genetics. I’ve done a great deal of testing and people ask me whether I’m concerned about biotech seeds,” he said. “Well, I’m not.”
Stahr has a small farm. Like many farmers, he’s seen good results — even during last year’s drought —from seeds containing modern traits, including genetically engineered ones. Within the scientific community, though, there is some recognition that the safety demonstrated today can’t predict the ultimate impact on humans, plants or the environment. Several states, including Iowa and Missouri, are considering mandatory labeling of foods containing genetically modified organisms — which is many. More than 90 percent of the country’s corn and soybeans contain GMOs, which means they’re in products from cereal to candy to soda.