Maize cytosolic NADP-malic enzyme (ZmCytNADP-ME): a phylogenetically distant isoform specifically expressed in embryo and emerging roots
Maize cytosolic NADP-malic enzyme (ZmCytNADP-ME): a phylogenetically distant isoform specifically expressed in embryo and emerging roots
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DOI：
10.1007/s11103-008-9375-8
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发表时间：
2008-11-01
影响因子：
5.1
通讯作者：
Drincovich, Maria F.
中科院分区：
文献类型：
--
作者：
Detarsio, Enrique;Maurino, Veronica G.;Drincovich, Maria F.
玉米质体NADP-苹果酸酶有两种同工型：位于维管束鞘的光合同工型（ZmC（4）-NADP-ME）和组成型表达的同工型（Zm-nonC（4）-NADP-ME）。在这项工作中，第一个玉米胞质NADP-ME（ZmCytNADP-ME）的特性，该转录本是专门发现在胚胎和新兴的根。ZmCytNADP-ME在根中的表达随着发育而降低，而Zm-nonC（4）-NADP-ME伴随着增加。另一方面，ZmCytNADP-ME的积累受几种胁迫条件的差异调节，并显示出与玉米幼根中Zm-nonC（4）-NADP-ME的协调。重组ZmCytNADP-ME显示明显不同的动力学参数和代谢调控比质体亚型。这种新的异构体的特殊性质和特异性表达模式表明，它可能参与控制细胞溶质苹果酸水平在新兴的根，如。G.在缺氧的时候。ZmCytNADP-ME与其他胞质单核细胞和双子叶细胞NADP-ME具有遗传相关性，数据表明它属于植物NADP-ME中的一个祖先独特的组。
Two maize plastidic NADP-malic enzyme isoforms have been characterized: the bundle sheath-located photosynthetic isoform (ZmC(4)-NADP-ME) and a constitutively expressed one (Zm-nonC(4)-NADP-ME). In this work, the characterization of the first maize cytosolic NADP-ME (ZmCytNADP-ME) is presented, which transcript is exclusively found in embryo and emerging roots. ZmCytNADP-ME expression in roots decreases with development, while Zm-nonC(4)-NADP-ME increases concomitantly. On the other hand, ZmCytNADP-ME accumulation is differentially modulated by several stress conditions and shows coordination with that of Zm-nonC(4)-NADP-ME in maize young roots. Recombinant ZmCytNADP-ME displays clearly distinct kinetic parameters and metabolic regulation than the plastidic isoforms. The particular properties and the specific-expression pattern of this novel isoform suggest that it may be involved in the control of cytosolic malate levels in emerging roots, e. g. during hypoxia. ZmCytNADP-ME is phylogenetically related to other cytosolic mono and dicot NADP-MEs, and data indicate that it belongs to an ancestral unique group among plant NADP-MEs.