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United States Department of Agriculture

Agricultural Research Service

Research Project: DISCOVERY AND DEVELOPMENT OF NATURAL PRODUCT-BASED WEED MANAGEMENT METHODS

Location: Natural Products Utilization Research

Title: Mode of Action of Glyphosate

Authors
item Velini, Edivaldo - UNIV. ESTADUAL-BRAZIL
item Duke, Stephen
item Trindade, Maria Lucia - PESQUISADORA – BIOATIVA
item Meschede, Dana - UNIV. ESTADUAL-BRAZIL
item Carbonari, Caio - UNIV. ESTADUAL-BRAZIL

Submitted to: Book Chapter
Publication Type: Book / Chapter
Publication Acceptance Date: June 1, 2008
Publication Date: May 3, 2009
Citation: Velini, E.D., Duke, S.O., Trindade, M.B., Meschede, D.K., Carbonari, C.A. 2009. Modo de acao do Glyphosate (Mode of Action of Glyphosate in Portuguese). In Glyphosate, E.D. Velini, D.K. Meschede, C.A. Carbonari, and M.L.B. Trindade, Eds., Fundaçã de Estudos e Pesquisas Agricoloas e Florestais. Botucato-SP, Brazil. pp. 113-133.

Interpretive Summary: Although glyphosate is the most used and studied herbicide in the world, the available information is not enough to fully understand its mode of action. The molecular site of action of glyphosate is the enzyme 5-enolpyruvlyshikimate-3-phosphate synthase (EPSPS). It is the only known compound that significantly affects this enzyme. Transgenic, herbicide-resistant plants that have genes for glyphosate-resistant EPSPS from microorganisms are highly resistant to glyphosate, proving that it this is the critical target site. Inhibition of EPSPS leads to reduced levels of aromatic amino acids (tryptophan, tyrosine, and phenylalanine) needed for protein, cell wall, and secondary plant product synthesis. Furthermore, inhibition of EPSPS causes deregulation of the shikimic acid pathway, leading to a general disruption of plant carbon metabolism. This latter process is poorly understood.

Technical Abstract: Although glyphosate is the most used and studied herbicide in the world, the available information is not enough to fully understand its mode of action. The molecular site of action of glyphosate is the enzyme 5-enolpyruvlyshikimate-3-phosphate synthase (EPSPS). It is the only known compound that significantly affects this enzyme. Transgenic, herbicide-resistant plants that have genes for glyphosate-resistant EPSPS from microorganisms are highly resistant to glyphosate, proving that it this is the critical target site. Inhibition of EPSPS leads to reduced levels of aromatic amino acids (tryptophan, tyrosine, and phenylalanine) needed for protein, cell wall, and secondary plant product synthesis. Furthermore, inhibition of EPSPS causes deregulation of the shikimic acid pathway, leading to a general disruption of plant carbon metabolism. This latter process is poorly understood.

Last Modified: 4/15/2014
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