What Does RoundUp Ready Mean?
- November 8, 2012 12:00 AM
Last week's blog explained some of the science behind GMO crops, and in particular examined Bt corn. Another type of GMO crop about which people often have questions and sometimes concerns is RoundUp Ready crops.
RoundUp Ready crops have been genetically modified to be resistant to the herbicide glyphosate – trade name RoundUp. Glyphosate is an inhibitor of the plant enzyme 5-enolpyruvylshikimate-3-phosphate synthase (EPSPS). Plants need EPSPS in order to make three critical amino acids – phenylalanine, tyrosine, and tryptophan. Since amino acids are the building blocks of proteins, if plants are not able to make these amino acids, their growth will be severely inhibited. Thus spraying plants – and weeds, of course, are just plants that we don't want! - with glyphosate greatly diminishes their growth. In contrast to plants, people do not synthesize these particular amino acids – we get them from the food that we eat. Because of this, there is no human equivalent of EPSPS, and so glyphosate is not a threat to human health.
Much of the concern surrounding the implementation of RoundUp Ready crops focuses on the idea that these crops will promote the use of glyphosate herbicides, with potentially harmful effects on people and the environment. Although it is certainly possible that at very high levels, glyphosate may be harmful to people, it is likely to be less harmful than other types of chemical herbicides, for the reason explained above – the known target of glyphosate-based herbicides is not present in people. A National Academies of Science 2010 report on GMO crop safety and environmental impact concurs with this prediction (Impact of Genetically Engineered Crops on Farm Sustainability in the United States, http://www.nap.edu/catalog.php?record_id=12804), stating that "GE soybeans, corn, and cotton are designed to be resistant to the herbicide glyphosate, which has fewer adverse environmental effects compared with most other herbicides used to control weeds."
Moving towards herbicide-free farming may be a realistic goal for some farmers. However, the majority of farmers will continue to rely on some type of herbicide in order to economically produce their product. RoundUp Ready crops make it more likely that these farmers will choose to use an environmentally-friendly method of weed control.