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首页> 外文期刊>Journal of Experimental Botany >Malate decarboxylases: evolution and roles of NAD(P)-ME isoforms in species performing C-4 and C-3 photosynthesis
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Malate decarboxylases: evolution and roles of NAD(P)-ME isoforms in species performing C-4 and C-3 photosynthesis

机译：苹果酸脱羧酶：进行C-4和C-3光合作用的物种中NAD（P）-ME同工型的进化和作用

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In the C-4 pathway of photosynthesis two types of malate decarboxylases release CO2 in bundle sheath cells, NADP- and NAD-dependent malic enzyme (NADP-ME and NAD-ME), located in the chloroplasts and the mitochondria of these cells, respectively. The C-4 decarboxylases involved in C-4 photosynthesis did not evolve de novo; they were recruited from existing housekeeping isoforms. NADP-ME housekeeping isoforms would function in the control of malate levels during hypoxia, pathogen defence responses, and microspore separation, while NAD-ME participates in the respiration of malate in the tricarboxylic acid cycle. Recently, the existence of three enzymatic NAD-ME entities in Arabidopsis, occurring by alternative association of two subunits, was described as a novel mechanism to regulate NAD-ME activity under changing metabolic environments. The C-4 NADP-ME is thought to have evolved from a C-3 chloroplastic ancestor, which in turn would have evolved from an ancient cytosolic enzyme. In this way, the C-4 NADP-ME would have emerged through gene duplication, acquisition of a new promoter, and neofunctionalization. In contrast, there would exist a unique NAD-ME in C-4 plants, which would have been adapted to perform a dual function through changes in the kinetic and regulatory properties of the C-3 ancestors. In addition to this, for the evolution of C-4 NAD-ME, insertion of promoters or enhancers into the single-copy genes of the C-3 ancestors would have changed the expression without gene duplication.
机译：在光合作用的C-4途径中，两种类型的苹果酸脱羧酶在束鞘细胞中释放CO2：NADP和NAD依赖性苹果酸酶（NADP-ME和NAD-ME），分别位于这些细胞的叶绿体和线粒体中。 。涉及C-4光合作用的C-4脱羧酶没有从头进化。他们是从现有的客房整理异构体中招募的。 NADP-ME管家同工型将在缺氧，病原体防御反应和小孢子分离过程中控制苹果酸水平，而NAD-ME在三羧酸循环中参与苹果酸的呼吸作用。最近，通过两个亚基的选择性结合，拟南芥中存在三个酶促NAD-ME实体，这被描述为一种在不断变化的代谢环境下调节NAD-ME活性的新机制。 C-4 NADP-ME被认为是从C-3的叶绿体祖先进化而来的，而C-3的叶绿体祖先又是从古老的细胞溶质酶进化而来的。这样，C-4 NADP-ME将通过基因复制，新启动子的获得和新功能化而出现。相反，在C-4植物中将存在一个独特的NAD-ME，它可以通过改变C-3祖先的动力学和调节特性来执行双重功能。除此之外，对于C-4 NAD-ME的进化，在C-3祖先的单拷贝基因中插入启动子或增强子会改变表达而没有基因重复。

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