Observation and identification of 2-C-methyl-d-erythritol-2,4-cyclopyrophosphate in horseweed and ryegrass treated with glyphosate

Glyphosate is the world’s most important and widely used herbicide with a global market forecast to exceed a million metric tons before end of the current decade. While using 31P NMR in vivo to determine the fate of glyphosate in horseweed (Conyza canadensis (L.) Cronquist), we observed the glyphosate-induced appearance of an unexpected phosphorous containing compound that, in some cases, presented at millimolar concentrations [X. Ge, D.A. d’Avignon, J.J.H. Ackerman, R.D. Sammons, Rapid vacuolar sequestration: the horseweed glyphosate resistance mechanism, Pest Manag. Sci. 66 (2010) 345–348.]. Additional studies showed appearance of the same compound could be induced in ryegrass (Lolium multiflorum Lam) and other plant species by glyphosate exposure. We have isolated and identified the phosphorous containing compound as 2-C-methyl-d-erythritol-2,4-cyclopyrophosphate (MEcPP), one of the intermediates of the methylerythritol 4-phosphate (MEP) pathway, which is critical in plants for the production of isoprenoids. Herein, we describe conditions under which MEcPP can be produced in plants as well as the isolation and characterization of this metabolite.

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► In vivo31P NMR of glyphosate treated weeds.
► Glyphosate treatment leads to accumulation of MEcPP, a key intermediate of the non-mevalonate (MEP) pathway in higher plants.
► Plant exposure to intense light and high temperatures increases glyphosate-initiated production of MEcPP.
► MEcPP extraction (from horseweed), purification, and structural identification are described.