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.
abstract: The 2-C-methyl-D-erythritol 4-phosphate (MEP) pathway leads to the synthesis of isopentenyl diphosphate 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 diphosphate. 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.
authors: São Paulo State University, Faculty of Agronomic Sciences, Botucatu, SP, Brazil.
authors: Natália
authors: N
authors: Corniani
authors: São Paulo State University, Faculty of Agronomic Sciences, Botucatu, SP, Brazil.
authors: Edivaldo D
authors: ED
authors: Velini
authors: São Paulo State University, Faculty of Agronomic Sciences, Botucatu, SP, Brazil.
authors: Ferdinando M L
authors: FM
authors: Silva
authors: National Center for Natural Products Research, School of Pharmacy, University of Mississippi, University, MS, United States of America.
authors: N P Dhammika
authors: NP
authors: Nanayakkara
authors: BASF SE, GVA/HC-B009, Ludwigshafen, Germany.
authors: Matthias
authors: M
authors: Witschel
authors: USDA-ARS Natural Products Utilization Research Unit, University, MS, United States of America.
authors: Franck E
authors: FE
authors: Dayan
mesh_terms: D001681:Biological Assay; D053898:Biosynthetic Pathways; D002338:Carotenoids / Q000096:biosynthesis*; D004305:Dose-Response Relationship, Drug; D055808:Drug Discovery; D004896:Erythritol / Q000031:analogs & derivatives* / Q000096:biosynthesis; D006540:Herbicides / Q000494:pharmacology*; D001467:Hordeum / Q000187:drug effects / Q000378:metabolism; D007555:Isoxazoles / Q000494:pharmacology*; D023303:Oxazolidinones / Q000494:pharmacology*; D013403:Sugar Phosphates / Q000096:biosynthesis*
chemical_list: C114232:2-C-methylerythritol 4-phosphate; D006540:Herbicides; D007555:Isoxazoles; D023303:Oxazolidinones; D013403:Sugar Phosphates; D002338:Carotenoids; C095255:clomazone; D004896:Erythritol