title: Expression of a bacterial feedback-insensitive 3-deoxy-D-arabino-heptulosonate 7-phosphate synthase of the shikimate pathway in Arabidopsis elucidates potential metabolic bottlenecks between primary and secondary metabolism.
abstract: The shikimate pathway of plants mediates the conversion of primary carbon metabolites via chorismate into the three aromatic amino acids and to numerous secondary metabolites derived from them. However, the regulation of the shikimate pathway is still far from being understood. We hypothesized that 3-deoxy-d-arabino-heptulosonate 7-phosphate synthase (DAHPS) is a key enzyme regulating flux through the shikimate pathway. To test this hypothesis, we expressed a mutant bacterial AroG gene encoding a feedback-insensitive DAHPS in transgenic Arabidopsis plants. The plants were subjected to detailed analysis of primary metabolism, using GC-MS, as well as secondary metabolism, using LC-MS. Our results exposed a major effect of bacterial AroG expression on the levels of shikimate intermediate metabolites, phenylalanine, tryptophan and broad classes of secondary metabolite, such as phenylpropanoids, glucosinolates, auxin and other hormone conjugates. We propose that DAHPS is a key regulatory enzyme of the shikimate pathway. Moreover, our results shed light on additional potential metabolic bottlenecks bridging plant primary and secondary metabolism.
authors.affiliation: Department of Plant Sciences, The Weizmann Institute of Science, Rehovot 76100, Israel.
authors.forename: Vered
authors.initials: V
authors.lastname: Tzin
authors.affiliation: Department of Plant Sciences, The Weizmann Institute of Science, Rehovot 76100, Israel.
authors.forename: Sergey
authors.initials: S
authors.lastname: Malitsky
authors.affiliation: The Institute of Plant Sciences and Genetics in Agriculture, Faculty of Agriculture, The Hebrew University of Jerusalem, PO Box 12, Rehovot 76100, Israel.
authors.forename: Michal Moyal Ben
authors.initials: MMB
authors.lastname: Zvi
authors.affiliation: Plant Biology Division, The Samuel Roberts Noble Foundation, Ardmore, OK 73401, USA.
authors.forename: Mohamed
authors.initials: M
authors.lastname: Bedair
authors.affiliation: Plant Biology Division, The Samuel Roberts Noble Foundation, Ardmore, OK 73401, USA.
authors.forename: Lloyd
authors.initials: L
authors.lastname: Sumner
authors.affiliation: Department of Plant Sciences, The Weizmann Institute of Science, Rehovot 76100, Israel.
authors.forename: Asaph
authors.initials: A
authors.lastname: Aharoni
authors.affiliation: Department of Plant Sciences, The Weizmann Institute of Science, Rehovot 76100, Israel.
authors.forename: Gad
authors.initials: G
authors.lastname: Galili
mesh_terms: D010723:3-Deoxy-7-Phosphoheptulonate Synthase / Q000378:metabolism*; D017360:Arabidopsis / Q000187:drug effects / Q000235:genetics* / Q000254:growth & development / Q000378:metabolism*; D004926:Escherichia coli / Q000187:drug effects / Q000201:enzymology*; D025461:Feedback, Physiological / Q000187:drug effects; D035264:Flowers / Q000187:drug effects / Q000235:genetics; D008401:Gas Chromatography-Mass Spectrometry; D015870:Gene Expression / Q000187:drug effects; D018506:Gene Expression Regulation, Plant / Q000187:drug effects; D008031:Lignin / Q000378:metabolism; D053858:Metabolic Networks and Pathways / Q000187:drug effects; D018547:Plant Stems / Q000187:drug effects / Q000235:genetics; D030821:Plants, Genetically Modified; D025341:Principal Component Analysis; D012765:Shikimic Acid / Q000378:metabolism*; D014364:Tryptophan / Q000031:analogs & derivatives / Q000494:pharmacology
chemical_list: C004182:5-methyltryptophan; D012765:Shikimic Acid; D014364:Tryptophan; D008031:Lignin; D010723:3-Deoxy-7-Phosphoheptulonate Synthase