title: Arabidopsis uses two gluconeogenic gateways for organic acids to fuel seedling establishment.
abstract: Gluconeogenesis is a fundamental metabolic process that allows organisms to make sugars from non-carbohydrate stores such as lipids and protein. In eukaryotes only one gluconeogenic route has been described from organic acid intermediates and this relies on the enzyme phosphoenolpyruvate carboxykinase (PCK). Here we show that two routes exist in Arabidopsis, and that the second uses pyruvate, orthophosphate dikinase (PPDK). Gluconeogenesis is critical to fuel the transition from seed to seedling. Arabidopsis pck1 and ppdk mutants are compromised in seed-storage reserve mobilization and seedling establishment. Radiolabelling studies show that PCK predominantly allows sugars to be made from dicarboxylic acids, which are products of lipid breakdown. However, PPDK also allows sugars to be made from pyruvate, which is a major product of protein breakdown. We propose that both routes have been evolutionarily conserved in plants because, while PCK expends less energy, PPDK is twice as efficient at recovering carbon from pyruvate.
authors: Department of Plant Biology and Crop Science, Rothamsted Research, West Common, Harpenden, Hertfordshire AL5 2JQ, UK.
authors: Peter J
authors: PJ
authors: Eastmond
authors: Department of Plant Sciences, University of Cambridge, Downing Street, Cambridge CB2 3EA, UK.
authors: Holly M
authors: HM
authors: Astley
authors: Department of Plant Sciences, University of Cambridge, Downing Street, Cambridge CB2 3EA, UK.
authors: Kate
authors: K
authors: Parsley
authors: Department of Plant Sciences, University of Cambridge, Downing Street, Cambridge CB2 3EA, UK.
authors: Sylvain
authors: S
authors: Aubry
authors: Department of Plant Sciences, University of Cambridge, Downing Street, Cambridge CB2 3EA, UK.
authors: Ben P
authors: BP
authors: Williams
authors: Department of Plant Biology and Crop Science, Rothamsted Research, West Common, Harpenden, Hertfordshire AL5 2JQ, UK.
authors: Guillaume N
authors: GN
authors: Menard
authors: Department of Plant Biology and Crop Science, Rothamsted Research, West Common, Harpenden, Hertfordshire AL5 2JQ, UK.|College of Natural and Agricultural Sciences, Center for Plant Cell Biology, University of California, Riverside, California 92521, USA.
authors: Christian P
authors: CP
authors: Craddock
authors: Max-Planck-Insitüt für Molekulare Pflanzenphysiologie, Am Mühlenberg 1, Potsdam-Golm D-14476, Germany.|Departmento de Biologia Vegetal, Universidade Federal de Vicosa, Vicosa, Minas Gerais 36570-000, Brazil.
authors: Adriano
authors: A
authors: Nunes-Nesi
authors: Max-Planck-Insitüt für Molekulare Pflanzenphysiologie, Am Mühlenberg 1, Potsdam-Golm D-14476, Germany.
authors: Alisdair R
authors: AR
authors: Fernie
authors: Department of Plant Sciences, University of Cambridge, Downing Street, Cambridge CB2 3EA, UK.
authors: Julian M
authors: JM
authors: Hibberd
mesh_terms: D017360:Arabidopsis / Q000235:genetics / Q000254:growth & development / Q000378:metabolism*; D002241:Carbohydrates / Q000096:biosynthesis; D002244:Carbon / Q000378:metabolism; D003998:Dicarboxylic Acids / Q000378:metabolism; D018506:Gene Expression Regulation, Plant; D005943:Gluconeogenesis / Q000235:genetics*; D050356:Lipid Metabolism / Q000235:genetics; D009154:Mutation; D010730:Phosphoenolpyruvate Carboxylase / Q000235:genetics / Q000378:metabolism*; D011772:Pyruvate, Orthophosphate Dikinase / Q000235:genetics / Q000378:metabolism*; D019289:Pyruvic Acid / Q000378:metabolism; D036226:Seedlings / Q000235:genetics / Q000254:growth & development / Q000378:metabolism*; D012639:Seeds / Q000235:genetics / Q000254:growth & development / Q000378:metabolism*; D015398:Signal Transduction
chemical_list: D002241:Carbohydrates; D003998:Dicarboxylic Acids; D002244:Carbon; D019289:Pyruvic Acid; D011772:Pyruvate, Orthophosphate Dikinase; D010730:Phosphoenolpyruvate Carboxylase