Glyphosate is the world's most widely used herbicide due to favorable attributes of low cost, low toxicity, and high efficacy in controlling a wide range of weed species. The genetic engineering of important crops with the glyphosate-tolerant trait has led to extensive and largely exclusive glyphosate usage in many areas. The resulting selective evolutionary pressure has resulted in the emergence of glyphosate-resistant weed biotypes. Glyphosate contains a phosphonate (-CPO3 2-) chemical group, with variable protonation depending upon pH, that provides for convenient detection and monitoring via 31P NMR in plant tissue extracts as well as in vivo. Insights provided through 31PNMR studies of weed species exposed to glyphosate have improved our understanding of herbicide uptake and compartmentalization, resulting in key insights regarding resistance mechanisms. For example, we have previously reported the discovery and characterization of glyphosate vacuole sequestration as the principal resistance mechanism in horseweed (Conyza canadensis) and in ryegrass (Lolium spp.) from several continents. Herein, we expand our prior published 31P-NMR studies to include additional weed biotypes, characterizing glyphosate uptake, vacuole sequestration and chloroplast exclusion.
|Title of host publication||Handbook on Herbicides|
|Subtitle of host publication||Biological Activity, Classification and Health and Environmental Implications|
|Publisher||Nova Science Publishers, Inc.|
|Number of pages||29|
|State||Published - Jan 1 2013|