Differential Contribution of Malic Enzymes during Soybean and Castor Seeds Maturation

GERRARD WHEELER, M.C.; ARIAS, C.L.; RIGHINI, S.; BADIA, M.B.; ANDREO, C.S.; DRINCOVICH, M.F.; SAIGO, M.

PLOS ONE

PUBLIC LIBRARY SCIENCE

Lugar: San Francisco; Año: 2016

1932-6203

Malic enzymes (ME) catalyze the decarboxylation of malate generating pyruvate, CO2and NADH or NADPH. In some organisms it has been established that ME is involvedin lipids biosynthesis supplying carbon skeletons and reducing power. In this work westudied the MEs of soybean and castor, metabolically different oilseeds. Thecomparison of enzymatic activities, transcript profiles and organic acid contentssuggest different metabolic strategies operating in soybean embryo and castorendosperm in order to generate precursors for lipid biosynthesis. In castor, the malateaccumulation pattern agrees with a central role of this metabolite in the provision ofcarbon to plastids, where the biosynthesis of fatty acids occurs. In this regard, thegenome 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 fattyacids synthesis in the last stages of seed filling. These findings provide new insightsinto intermediary metabolism in oilseeds and provide new biotechnological targets toimprove oil yields.