Future potatoes

Potatoes not only reveal essential characteristics of the past and the present, but they foretell our future too. Genetic manipulation of potatoes through selective breeding started on the terraces at Macchu Pichu thousands of years ago. Now genetic manipulation continues in the laboratories of the first world for the fields of the third world. Like a snailshell curving back around to where it began, but bigger than when it started, genetically engineered potatoes are part of a whole movement of genetically engineered foods infiltrating farmers’ fields and storming supermarket shelves. Instead of being confined by the principles of natural selection and naturally occurring genetic variation within a species, genetic engineering combines the genes of different species, so that plants have insect, bacteria, or animal genes within their cells. This produces soybeans resistant to an herbicide, or potatoes complete with sticky hairs to catch bugs. Now scientists can produce transgenic potatoes that contain vaccines within their cells for deadly diseases like E. coli and cholera.

In countries without adequate water, sanitation, or medical facilities, cholera and other diarrheal diseases are responsible for one-third of the deaths of children under 5 and one-quarter of the deaths of children between five and 14. Doctors must keep children with these diseases hydrated, but large amounts of unsanitary water may contain even more dangerous diseases. However, these countries without sanitary water usually don’t have the adequate refrigeration or transportation infrastructures needed to preserve and administer traditional vaccines either. Seeing these problems, a team of scientists including Charles J. Arntzen put together recent work in plant genetics and edible vaccines to deliver a vaccine within the raw tuber of the potato plant. Arntzen wrote about the research behind the idea in a 1997 article for Public Health Reports.

Bacteria like E. coli and cholera have two parts: a binding protein sub-unit that attaches to cells in the intestinal walls and an enzyme activated by the first protein that actually causes the disease. The binding sub-unit attaches to the intestinal walls and activates the enzyme. The enzyme changes the environment of the cells in the intestinal walls so that water flows out of the cells and the body in very thin diarrhea, and the patient becomes massively dehydrated. But the body will produce an immune response with the presence of just the first binding protein subunit. The first piece of inspiration, Arntzen writes, came from current work producing vaccines from "recombint" organisms--organisms with genes combined from two or more species. Scientists can produce vaccines by combining the genes of a pathogen with the genes of another organism like yeast. The new organism produces antigens like the pathogen but does not actually cause the disease. The antigens produced by the recombint organism can be distilled into injectable vaccines that produce antibodies in the blood or edible vaccines that produce an immune response in the mucous of the gut. The second piece inspiring the creation of plant-based vaccines was the agricultural revolution which led scientists to think about plant genetics in a whole new way. Scientists can combine and manipulate plant genes which produce resistances to the mortal enemies of agricultural plants like insects and herbicides. Combining these two ideas, Arntzen and his team worked to produce a plant that would contain genes to produce the binding protein subunit of E. coli and cholera.

After initial experiments with hepatitis B and tobacco plants (both genomes have been extensively mapped and experimented with), the team moved on to experiments with potatoes, E coli, and cholera. They used potatoes because the plants grew and reproduced quickly, and test animals would eat them. The transgenic potatoes produced the right proteins, but generating enough of the proteins for a whole dose in a single potato caused cellular damage. In May of 1998 Vaccine Weekly reported "First Human Trial Shows that Edible Vaccine is Feasible."

At first this seems like a great leap for humankind, a glorious light for underdeveloped countries shining from the labs of benevolent scientists. But the situation is more complicated than that. Other scientists and citizens are concerned about transgenic plants and genetic engineering in general. We only know about the short-term effects of genetic engineering on these plants. The long-term effects on these plants and the environment could be dangerous. They worry about a practice motivated solely by short-term profits and not long-term sustainability. Research aimed at short-term profits has led to environmental disaster in the past--remember DDT? Even some of these short-term benefits are troublesome. For instance, the herbicide resistance of Roundup Ready soybeans has already passed over to the surrounding weeds. And boll weevil resistant cotton already has infestations of toxin-resistant bugs. When these plants and animals escape into the wild they could wreak havoc on the natural ecosystem. Many religious organizations object to tampering with such basic patterns of life as DNA and worry about the ethical aspects of combining the genes of different species. Europeans refuse to eat or trade genetically modified foodstuffs, and lots of citizens in the US are lobbying for labels on genetically engineered food. This new plant-based vaccine proposes shipping a product to poorer countries as humanitarian aid that we probably would refuse to eat ourselves. This suggests all sorts of disturbing things about what first world countries think of third world countries. Perhaps they are not quite worthy of the high ethical and environmental standards we hold so important in America and Europe. It reveals an attitude in first world countries that third world countries are children that need parenting. As we look at potatoes in the future, we must demand answers to questions about the place of biotechnology in the everyday life and health of the planet and the people on it.