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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: Novel bioassay for the discovery of inhibitors of the 2-C-Methyl-D-Erythritol 4-Phosphate (MEP) and terpenoid pathways leading to carotenoid biosynthesis

Authors
item Corniani, Natália -
item Velini, Edivaldo -
item Silva, Ferdinando M. L -
item Nanayakkara, Dhammika N.P. -
item Witschel, Matthias -
item Dayan, Franck

Submitted to: PLoS One
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: July 1, 2014
Publication Date: July 31, 2014
Citation: Corniani, N., Velini, E.D., Silva, F., Nanayakkara, D., Witschel, M., Dayan, F.E. 2014. Novel bioassay for the discovery of inhibitors of the 2-C-Methyl-D-Erythritol 4-Phosphate (MEP) and terpenoid pathways leading to carotenoid biosynthesis. PLoS One. 98:E103704.

Interpretive Summary: The synthesis of carotenoids is an important pathway for herbicide discovery. We have developed a new, simple and inexpensive bioassay that can detect the activity of compounds inhibiting this pathway. This concept was tested with known inhibitors of steps of the MEP pathway and validated against representative herbicides known to target processes outside of the pathways involved in the synthesis of carotenoids. This assay enables the rapid screen of new inhibitors of enzymes preceding the synthesis of phytoene, though there are some limitations related to the non-specific effect of some inhibitors on this assay.

Technical Abstract: The 2-C-methyl-D-erythritol 4-phosphate (MEP) pathway leads to the synthesis of isopentenyl-phosphate (IPP) in plastids. It is a major branch point providing precursors for the synthesis of carotenoids, tocopherols, plastoquinone and the phytyl chain of chlorophylls, as well as the hormones abscisic acid and gibberellins. Consequently, disruption of this pathway is harmful to plants. We developed an in vivo bioassay that can measure the carbon flow through the carotenoid pathway. Leaf cuttings are incubated in the presence of a phytoene desaturase inhibitor to induce phytoene accumulation. Any compound reducing the level of phytoene accumulation is likely to interfere with either one of the steps in the MEP pathway or the synthesis of geranylgeranyl pyrophosphate. This concept was tested with known inhibitors of steps of the MEP pathway. The specificity of this in vivo bioassay was also verified by testing representative herbicides known to target processes outside of the MEP and carotenoid pathways. This assay enables the rapid screen of new inhibitors of enzymes preceding the synthesis of phytoene, though there are some limitations related to the non-specific effect of some inhibitors on this assay.

Last Modified: 11/21/2014
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