Differential Contribution of Malic Enzymes during Soybean and Castor Seeds Maturation.
Differential Contribution of Malic Enzymes during Soybean and Castor Seeds Maturation.
复制标题
DOI：
10.1371/journal.pone.0158040
复制
发表时间：
2016
期刊：
影响因子：
3.7
通讯作者：
Saigo M
中科院分区：
文献类型：
--
作者：
Gerrard Wheeler MC;Arias CL;Righini S;Badia MB;Andreo CS;Drincovich MF;Saigo M
苹果酸酶 (ME) 催化苹果酸脱羧生成丙酮酸、CO2 和 NADH 或 NADPH。在一些生物体中，已经确定 ME 参与脂质生物合成，提供碳骨架并还原能量。在这项工作中，我们研究了大豆和蓖麻这两种代谢不同的油籽的 ME。酶活性、转录谱和有机酸含量的比较表明，大豆胚和蓖麻胚乳中存在不同的代谢策略，以产生脂质生物合成的前体。在蓖麻中，苹果酸的积累模式与该代谢物在向质体提供碳方面的核心作用一致，而脂肪酸的生物合成发生在质体中。在这方面，蓖麻的基因组拥有编码假定的质体NADP-ME的单个基因，当脂质沉积活跃时，其表达水平很高。另一方面，NAD-ME 对大豆胚的成熟具有重要贡献，可能推动碳从线粒体转移到质体，以支持种子灌浆最后阶段的脂肪酸合成。这些发现为油籽的中间代谢提供了新的见解，并为提高油产量提供了新的生物技术目标。
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.