Need for Detecting GMOs?
Patricia, a producer in Eastern Nebraska, grows predominantly corn and soybeans, two important crops for that state. She encounters significant challenges each growing season. One major challenge is controlling European corn borer that, in some years, causes significant yield loss in her corn crop. Another challenge is weed control, which can require many hours of her time to till the fields with a tractor and implement (Figure 1). Alternatively, she can use a different tillage system which utilizes herbicides, but these chemicals can harm her crops or not effectively control weeds.
She is also looking for other viable markets for her crops, so a more nutritious soybean variety might open new opportunities for her. Like any successful business person, Patricia continually looks for ways to address the challenges in her enterprise.
Advances in biotechnology have provided tools to growers such as Patricia that address these types of challenges. Through biotechnology, novel DNA sequences, from unrelated species, can be inserted into the chromosomes of plants, enabling them to express new traits. Bt corn for example, expresses a trait that was derived from the bacterium, Bacillus thuringensis.
This Bt variety of corn does not require the application of pesticides, but is inherently lethal to the European corn borer (for more information see European Corn Borer and Bacillus thuringiensis). Roundup Ready corn and Roundup Ready soybeans (Figure 2) allow producers to spray glyphosate herbicides to control weeds, while leaving the crop unharmed (see Inhibitors of Aromatic Amino Acid Biosynthesis). This provides excellent weed control, leading to higher yields. At the same time, it minimizes tillage required, which can reduce soil erosion and fuel costs. Research developments are currently underway to produce crops with enhanced nutritional characteristics such as high oleic soybean, a more nutritious and healthy soybean for consumers (Buhr et al., 2002).
As these examples suggest, transgenic technology has introduced traits into food and fiber crops that are attractive to producers and the technology has the potential to provide many traits that meet the needs of specific consumers. As a result, there is a growing need for the development of technologies that detect transgenes and identify transgenic crops in the food, feed and fiber markets. For example scientists who insert transgenes into crop varieties using biotechnology processes utilize laboratory procedures to monitor their success (Figure 3).
Plant breeders who cross these novel genes into plant germplasm can benefit from efficient methods to distinguish plants that are homozygous (two copies) as hemizygous (one copy) for the transgene. Similarly, detection techniques are needed for researchers interested in understanding potential impacts of the escape of these transgenes (gene flow) to non-adapted germplasm pools. Finally, sometimes consumers, regulators and food processors are interested in knowing whether the foods they are purchasing contain genes inserted by means of biotechnology.
Discussion Question : Why would a scientist need DNA information about a biotechnology-enhanced crop?
Answer: They may need to know if the gene, and how many copies of it, successfully integrated into a plant.
Discussion Question :
Why would a consumer be interested in the DNA characteristics of a crop?
Answer: They may be more comfortable in buying foods which contain only very low amounts of the transgenic variety.