中文摘要：

【目的】克隆苹果（Malus×domestica B.）中苹果酸代谢的关键酶基因MdNADP-ME,进行序列特征分析,研究MdNADP-ME在苹果中组织表达的情况。【方法】利用RT-PCR技术获得苹果MdNADP-ME1,2,3全长的cDNA序列。对该序列进行生物信息学分析,采用荧光实时定量PCR技术研究MdNADP-ME1,2,3的组织表达。【结果】测序结果显示,获得的3个NADP-苹果酸酶基因（MdNADP-ME1、MdNADP-ME2和MdNADP-ME3;GenBank登录号为JX971883、JX971884和JX971885）,其ORF分别为1 512、1 782和1 926 bp,推测其分别编码503、593和641个氨基酸的多肽。氨基酸序列和结构分析显示,这3个基因均含有5个保守的氨基酸区域（motif I-V）,含有2个功能结构域：malic和NAD_bind_1_malic_enz。进化树分析结果显示,MdNADP-ME1和MdNADP-ME2属于双子叶植物细胞质NADP-ME型,MdNADP-ME3属于双子叶植物质体NADP-ME型。荧光实时定量PCR结果表明,MdNADP-ME1-3在被检测的组织中均有表达,但表达差异明显。【结论】MdNADP-ME1-3属于植物NADP-ME家族,结构高度保守,并且在苹果的不同组织中有不同表达模式。

英文摘要：

[Objective] This study is aimed to characterize the genes of MdNADP-MEs involved in malic acid metabolism in MalusXdomestiea B. by gene cloning, sequence and expression of MdNADP-MEs in different tissues. [Method] Three full-length eDNA sequences of MdNADP-ME1,2,3 were isolated by RT-PCR. The obtained eDNA sequences and the deduced amino acid sequences were analyzed with bioinformatics methods, qRT-PCR was used to assess the expression of MdNADP-MEs in different tissues. [Result] The sequencing results showed that three cDNAs （designated as MdNADP-ME1, 2 and 3; GenBank Accession No. JX971883, JX971884 and JX971885） were 1 512 bp, 1 782 bp and 1 926 bp. They contained an open reading frame （ORF） of 1 512 bp, 1 782 bp and 1 926 bp, respectively, and their ORFs encoded an protein with 503, 593 and 641 amino acids, respectively. Amino acid sequence and structure analysis indicated that MdNADP-MEs contained five conservative amino acid areas （motif I-V） and two functional structure domains： malic and NAD_bind 1 malic_enz. The result of phylogenetic analysis showed that MdNADP-ME1 and 2 belonged to cytosolie dicot NADP-ME （group I）, MdNADP-ME3 belonged to plastidic dicot NADP-ME. qRT-PCR result showed that MdNADP-MEs were constitutively expressed in all examined tissues, but showed different expression levels. [ Conclusion ] MdNADP-ME 1,2,3 belong to NADP-ME family, possess highly conserved structures, and show different expression patterns in different tissues of apple.