Journal or Publishing Institution: Outlooks on Pest Management
Study: https://www.ars.usda.gov/ARSUserFiles/64022000/publications/reddy/nandula-grw12.pdf
Author(s): Nandula, V.K., Reddy, K.N., Duke, S.O. and Poston, D.H.
Article Type: Journal Publication
Record ID: 1711
Text: Glyphosate [N-(phosphonomethyl)glycine] is a non-selective, broad spectrum, systemic, post-emergence herbicide that has been used extensively throughout the world over the past three decades. It inhibits the biosynthesis of aromatic amino acids (phenylalanine, tryptophan, and tyrosine), which leads to several metabolic disturbances, including the inhibition of protein and secondary product biosynthesis (Franz et al., 1997) and the deregulation of the shikimate pathway, leading to general metabolic disruption (Duke et al., 2003).
Since the discovery of its herbicidal properties in 1971 and commercialization in 1974, glyphosate has been used extensively in both crop and non-crop lands. Because of its lack of selectivity, glyphosate use was initially limited to preplant, post-directed, and post-harvest applications for weed control. With the introduction of glyphosate-resistant (GR) crops in the mid 1990s, glyphosate is now widely used for weed control in GR crops without concern for crop injury. GR crops were created by stable integration of a transgene from Agrobacterium sp. that encodes for glyphosate-insensitive 5-enolpyruvylshikimate-3-phosphate synthase (EPSPS), the target enzyme of glyphosate in the shikimate pathway (Padgette et al., 1996). Expression of GR EPSPS enzyme helps to maintain normal aromatic amino acid levels in GR crops treated with glyphosate. GR canola, maize, cotton, and soybean have been commercialized in North America since 1996. GR crops are now grown in several countries, with particularly strong adoption in North America, Argentina, Brazil, and China. History, development, and adoption of herbicide-resistant crops in general and GR crops in particular and their impact on weed management are the topics of recent reviews (Dill, 2005; Duke, 2005; Reddy and Koger, 2005).
No evolved resistance to glyphosate was documented until GR rigid ryegrass (Lolium rigidum) was found in 1996 (Powles et al., 1998), about 20 years after the introduction of glyphosate. In recent years, the intense use of glyphosate in GR crops has increased selection pressure to evolve natural resistance to glyphosate in several weed populations. This article briefly summarizes the current status and potential future of glyphosate resistant weeds, as well as strategies to prevent future evolution of glyphosate resistant weeds…
Keywords: Herbicide resistance, herbicide resistance mechanisms, glyphosate,
GM crops, transgenic crops, weed
Citation: Nandula, V.K., Reddy, K.N., Duke, S.O. and Poston, D.H., 2005. Glyphosate-resistant weeds: Current status and future outlook. Outlooks on Pest Management, 16(4), p.183.
