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In plants, the NADP malic enzymes (NADP-MEs) are encoded by small gene families. These NADP-ME gene families are relatively well described in C4 plants but not well studied in C3 plants. In this study, we investigated the NADP-ME gene family in a model C3 monocot plant (rice, Oryza sativa) based on its recently released genomic DNA sequence. We found that the rice NADP-ME family is composed of four members, one plastidic NADP-ME and three cytosolic versions. Although the rice NADP-ME genes identified share a high degree of similarity with one another, one cytosolic NADP-ME (OscytME3) contains several unique amino acid substitutions within highly conserved amino acid regions. Phylogenetic analysis showed that OscytME3 might be derived from a different evolutionary branch than the other three rice genes. Expression analysis of the four rice NADP-ME genes indicated that each had a different tissue-specific and developmental profile, although all four responded to stress stimuli. 相似文献
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NADP-malic enzyme (NADP-ME, EC 1.1.1.40) functions in many different pathways in plant and may be involved in plant defense
such as wound and UV-B radiation. Here, expression of the gene encoding cytosolic NADP-ME (cytoNADP-ME, GenBank Accession No. AY444338) in rice (Oryza sativa L.) seedlings was induced by salt stress (NaCl). NADP-ME activities in leaves and roots of rice also increased in response
to NaCl. Transgenic Arabidopsis plants over-expressing rice cytoNADP-ME had a greater salt tolerance at the seedling stage than wild-type plants in MS medium-supplemented with different levels
of NaCl. Cytosolic NADPH/NADP+ concentration ratio of transgenic plants was higher than those of wild-type plants. These results suggest that rice cytoNADP-ME confers salt tolerance in transgenic Arabidopsis seedlings. 相似文献
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High level expression of C4-specific NADP-malic enzyme in leaves and impairment of photoautotrophic growth in a C3 plant, rice 总被引:8,自引:0,他引:8
Tsuchida H Tamai T Fukayama H Agarie S Nomura M Onodera H Ono K Nishizawa Y Lee BH Hirose S Toki S Ku MS Matsuoka M Miyao M 《Plant & cell physiology》2001,42(2):138-145
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In the C(4) pathway of photosynthesis two types of malate decarboxylases release CO(2) 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 neo-functionalization. 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. 相似文献
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Liu S Cheng Y Zhang X Guan Q Nishiuchi S Hase K Takano T 《Plant molecular biology》2007,64(1-2):49-58
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毛果杨NADP-苹果酸酶基因家族分析 总被引:1,自引:0,他引:1
本文分析C3树木毛果杨NADP-苹果酸酶(Populus trichocarpa NADP—malic enzyme,PtNADP-ME)基因家族及其表达特性。NADP—MEN源性检索表明,毛果杨基因组上存在5个PtNADP—ME基因,其中PtNADP-ME4编码区不完整。RT-PCRE及DNA测序结果表明,PtNADP-ME家族5个基因均转录表达。进化树构建显示,毛果杨PtNADP-ME家族5个成员分属于植物NADP—ME家族的3个进化分枝。半定量RT-PCR表明,5个PtNAP-ME家族基因没有明显的组织特异表达模式。然而,不同的PtNADP-ME基因转录表达对NaCI、PEG及甘露醇3种逆境胁迫应答与否以及应答方式存在明显的差异。 相似文献
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盐胁迫对库拉索芦荟叶片中NADP-苹果酸酶基因的诱导表达 总被引:4,自引:0,他引:4
为弄清景天酸代谢植物 库拉索芦荟中NADP 苹果酸酶 (NADP ME)基因的表达与其耐盐间的关系 ,根据已知NADP 苹果酸酶序列设计引物 ,从库拉索芦荟的 2个月幼苗中扩增克隆了NADP 苹果酸酶 4 96bp的cDNA片段 ,并对其进行了序列测定 ;选用敏感品种皂质芦荟和耐盐品种库拉索芦荟做材料 ,分别检测高盐胁迫条件下NADP ME的表达和NADP ME的活性。结果表明 ,两者在不同品种的芦荟中均被诱导 ,但诱导的强度与芦荟的耐盐程度相关。Northern杂交分析表明 ,高盐、干旱、外源ABA均能强烈诱导苹果酸酶的表达 ,但寒冷对其影响不大 ,这与库拉索芦荟的生物学特性相符合 ;此外 ,为了检测库拉索芦荟中NADP 苹果酸酶受盐诱导情况 ,利用Western印迹对样品进行了分析 ,结果显示高盐条件不仅明显诱导NADP ME的合成 ,而且随着处理时间的延长其合成量也在增多。 相似文献
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Effect of hypermethylation of CCWGG sequences in DNA of Mesembryanthemum crystallinum plants on their adaptation to salt stress 总被引:5,自引:0,他引:5
Dyachenko OV Zakharchenko NS Shevchuk TV Bohnert HJ Cushman JC Buryanov YI 《Biochemistry. Biokhimii?a》2006,71(4):461-465
Under salt stress conditions, the level of CpNpG-methylation (N is any nucleoside) of the nuclear genome of the facultative halophyte Mesembryanthemum crystallinum in the CCWGG sequences (W = A or T) increases two-fold and is coupled with hypermethylation of satellite DNA on switching-over of C3-photosynthesis to the crassulacean acid metabolism (CAM) pathway of carbon dioxide assimilation. The methylation pattern of the CCWGG sequences is not changed in both the 5'-promoter region of the gene of phosphoenolpyruvate carboxylase, the key enzyme of C4-photosynthesis and CAM, and in the nuclear ribosomal DNA. Thus, a specific CpNpG-hypermethylation of satellite DNA has been found under conditions of expression of a new metabolic program. The functional role of the CpNpG-hypermethylation of satellite DNA is probably associated with formation of a specialized chromatin structure simultaneously regulating expression of a large number of genes in the cells of M. crystallinum plants on their adaptation to salt stress and switching-over to CAM metabolism. 相似文献
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Primary Metabolism in Plant Defense (Regulation of a Bean Malic Enzyme Gene Promoter in Transgenic Tobacco by Developmental and Environmental Cues) 总被引:1,自引:0,他引:1 下载免费PDF全文
NADP-dependent malic enzyme (NADP-ME, EC 1.1.1.40) catalyzes the oxidative decarboxylation of malate to pyruvate, producing CO2 and NADPH. We have examined regulatory properties of a 2.8-kb promoter-leader fragment of a bean (Phaseolus vulgaris L.) NADP-ME gene (PvME1) predicted to encode a cytosolic form of the enzyme by expression analysis of promoter-[beta]-glucuronidase fusions in transgenic tobacco plants. The PvME1 promoter directed strong expression in stems, which was confined to vascular and pith tissues, and was also active in floral and reproductive tissues. Wounding caused a marked induction of promoter activity, which was further strongly enhanced upon application of stimuli related to pathogen defense. Glutathione (reduced form) was the strongest inducer, but oxidized glutathione, fungal elicitor, cellulase, catalase, ascorbic acid, and NADPH were additional potent promoter-stimulating agents. Responsiveness to reduced glutathione was also shown at the level of PvME1 mRNA accumulation in bean plants. The putative contributions of NADP-ME gene expression to the plant defense response and possible mechanisms of defense gene regulation by conditions of oxidative stress as well as by H2O2 and antioxidant levels are discussed. 相似文献
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NADP-malic enzyme (NADP-ME) (E.C. 1.1.1.40) is situated in the cytosol of Drosophila melanogaster. Both the tissue activity and CRM level of NADP-ME parallel changes in the dosage of a gene, Men+, located in region 87C2-3 to 87D1-2 of the third chromosome. The tissue activity of NADP-ME is very high in early third instar larvae, providing about 33% of the NADPH at this life stage. The tissue activity declines during pupal development but increases as the adult ages. The concentration of NADP-ME CRM and tissue activity are coordinately increased in third instar larvae by dietary carbohydrate and decreased by dietary lipid. 相似文献
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Takaomi Fushimi Masaaki Umeda Tetsuo Shimazaki Atsushi Kato Kinya Toriyama Hirofumi Uchimiya 《Plant molecular biology》1994,24(6):965-967
We have isolated a rice cDNA clone that is homologous to the gene for the maize NADP-dependent malic enzyme (EC 1.1.1.40; NADP-ME). The deduced amino acid sequence coded for by the cDNA indicates a high level of homology to chloroplast type NADP-ME, including a transit peptide with pronounced hydrophobic properties at the amino terminus. Northern blot analysis indicates that the expression of this gene is regulated by external stress such as submergence. 相似文献
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Phosphoenolpyruvate carboxylase from pennywort (Umbilicus rupestris). Changes in properties after exposure to water stress. 总被引:2,自引:0,他引:2 下载免费PDF全文
Umbilicus rupestris (pennywort) switches from C3 photosynthesis to an incomplete form of crassulacean acid metabolism (referred to as 'CAM-idling') when exposed to water stress (drought). This switch is accompanied by an increase in the activity of phosphoenolpyruvate carboxylase. This enzyme also shows several changes in properties, including a marked decrease in sensitivity to acid pH, a lower Km for phosphoenolpyruvate, very much decreased sensitivity to the allosteric inhibitor malate, and increased responsiveness to the allosteric effector glucose 6-phosphate. The Mr of the enzyme remains unchanged, at approx. 185 000. These changes in properties of phosphoenolpyruvate carboxylase are discussed in relation to the roles of the enzyme in C3 and in CAM plants. 相似文献
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