Journal or Publishing Institution: Proceedings of the National Academy of Sciences
Study: https://web.archive.org/web/20180823123513/http://www.pnas.org/content/107/3/955.short
Author(s): Powles, S.B.
Article Type: Journal Publication
Record ID: 1942
Text: In a world of more than 6 billion people, humans heavily rely on the dependable cultivation of the global food grain crops: rice, wheat, soybeans, maize (and cotton for fiber). History shows that threats to food production have major repercussions, including famine, war, and civil unrest. A major threat to food production occurs every single growing season, when wild plant species (weeds) infest crop fields. Humans have battled since the dawn of agriculture to control weeds and to minimize their negative influence on food production. Modern herbicides have largely replaced human labor as the primary tool for weed control, and this has contributed significantly to the productivity of world cropping. However, despite the success of herbicides, weeds remain a primary challenge to food production, in part because selection pressure from herbicides has resulted in the evolution of herbicide resistance in weeds. A current and important example is evolved resistance to the world’s most important herbicide, glyphosate (1). Glyphosate resistance evolution is a major adverse development because glyphosate is a one in a 100-year discovery that is as important for reliable global food production as penicillin is for battling disease. The report by Gaines et al. (2) in this issue of PNAS shows how one economically important weed species has evolved glyphosate resistance via gene amplification.
In the past decade there has been a revolution in world cropping with the advent and widespread adoption in the Americas of transgenic soybean, maize, cotton, and canola crops (3). In these crops engineered to be glyphosate resistant, this herbicide removes infesting weeds without any damage to the crop. The massive adoption of transgenic glyphosate-resistant crops has meant excessive reliance on glyphosate for weed control across vast areas. In evolutionary terms, widespread and persistent glyphosate use without diversity in weed control practices is a strong selection pressure for weeds able to survive glyphosate. Genes endowing glyphosate resistance are initially very rare; however, repeated use of glyphosate without diversity selects for such rare glyphosate resistance genes. This is occurring particularly in areas with transgenic glyphosate-resistant crops, where glyphosate is repeatedly used as the only weed control measure. Inevitably, glyphosate resistance is evolving in many important weed species (1). In some but not all parts of the world, glyphosate resistance evolution can no longer be prevented, and therefore resistance must be managed. Globally, no weed control tools are as good as glyphosate, and its potential widespread loss because of resistance is a looming threat to global cropping and food production…
Keywords: Amaranthus palmeri, plants, amplification, genes, genetic engineering, glyphosate, herbicide resistance, herbicide resistant weeds, herbicides, molecular genetics, selection pressure, weeds, biochemical genetics, genetic manipulation, weedicides, weedkillers; Chromosomes, chloroplasts, soybeans, maize, cotton, transgenic, shikimate
Citation: Powles, S.B., 2010. Gene amplification delivers glyphosate-resistant weed evolution. Proceedings of the National Academy of Sciences, 107(3), pp.955-956.
