title: Differential Contribution of Malic Enzymes during Soybean and Castor Seeds Maturation.
abstract: Malic enzymes (ME) catalyze the decarboxylation of malate generating pyruvate, CO2 and NADH or NADPH. In some organisms it has been established that ME is involved in lipids biosynthesis supplying carbon skeletons and reducing power. In this work we studied the MEs of soybean and castor, metabolically different oilseeds. The comparison of enzymatic activities, transcript profiles and organic acid contents suggest different metabolic strategies operating in soybean embryo and castor endosperm in order to generate precursors for lipid biosynthesis. In castor, the malate accumulation pattern agrees with a central role of this metabolite in the provision of carbon to plastids, where the biosynthesis of fatty acids occurs. In this regard, the genome of castor possesses a single gene encoding a putative plastidic NADP-ME, whose expression level is high when lipid deposition is active. On the other hand, NAD-ME showed an important contribution to the maturation of soybean embryos, perhaps driving the carbon relocation from mitochondria to plastids to support the fatty acids synthesis in the last stages of seed filling. These findings provide new insights into intermediary metabolism in oilseeds and provide new biotechnological targets to improve oil yields.
authors.affiliation: Centro de Estudios Fotosintéticos y Bioquímicos (CEFOBI-CONICET), Universidad Nacional de Rosario (UNR), Rosario, Santa Fe, Argentina.
authors.forename: Mariel Claudia
authors.initials: MC
authors.lastname: Gerrard Wheeler
authors.affiliation: Centro de Estudios Fotosintéticos y Bioquímicos (CEFOBI-CONICET), Universidad Nacional de Rosario (UNR), Rosario, Santa Fe, Argentina.
authors.forename: Cintia Lucía
authors.initials: CL
authors.lastname: Arias
authors.affiliation: Centro de Estudios Fotosintéticos y Bioquímicos (CEFOBI-CONICET), Universidad Nacional de Rosario (UNR), Rosario, Santa Fe, Argentina.
authors.forename: Silvana
authors.initials: S
authors.lastname: Righini
authors.affiliation: Centro de Estudios Fotosintéticos y Bioquímicos (CEFOBI-CONICET), Universidad Nacional de Rosario (UNR), Rosario, Santa Fe, Argentina.
authors.forename: Mariana Beatriz
authors.initials: MB
authors.lastname: Badia
authors.affiliation: Centro de Estudios Fotosintéticos y Bioquímicos (CEFOBI-CONICET), Universidad Nacional de Rosario (UNR), Rosario, Santa Fe, Argentina.
authors.forename: Carlos Santiago
authors.initials: CS
authors.lastname: Andreo
authors.affiliation: Centro de Estudios Fotosintéticos y Bioquímicos (CEFOBI-CONICET), Universidad Nacional de Rosario (UNR), Rosario, Santa Fe, Argentina.
authors.forename: María Fabiana
authors.initials: MF
authors.lastname: Drincovich
authors.affiliation: Centro de Estudios Fotosintéticos y Bioquímicos (CEFOBI-CONICET), Universidad Nacional de Rosario (UNR), Rosario, Santa Fe, Argentina.
authors.forename: Mariana
authors.initials: M
authors.lastname: Saigo
mesh_terms: D002244:Carbon / Q000378:metabolism; D002367:Ricinus communis / Q000201:enzymology* / Q000254:growth & development; D050356:Lipid Metabolism; D008291:Malate Dehydrogenase / Q000378:metabolism*; D010940:Plant Proteins / Q000378:metabolism*; D018087:Plastids / Q000378:metabolism; D012639:Seeds / Q000201:enzymology* / Q000254:growth & development; D013025:Glycine max / Q000201:enzymology* / Q000254:growth & development
chemical_list: D010940:Plant Proteins; D002244:Carbon; D008291:Malate Dehydrogenase; C046446:malate dehydrogenase-(oxaloacetate-decarboxylating) (NAD+)