Mild Reductions in Mitochondrial Citrate Synthase Activity Result in a Compromised Nitrate Assimilation and Reduced Leaf Pigmentation But Have No Effect on Photosynthetic Performance or Growth1[W]
Mild Reductions in Mitochondrial Citrate Synthase Activity Result in a Compromised Nitrate Assimilation and Reduced Leaf Pigmentation But Have No Effect on Photosynthetic Performance or Growth1[W]
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DOI：
10.1104/pp.108.117978
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发表时间：
2008-03
期刊：
影响因子：
7.4
通讯作者：
Agata Sienkiewicz-Porzucek;A. Nunes‐Nesi;Ronan Sulpice;J. Lisec;D. Centeno;P. Carillo;Andrea Leisse;Ewa Urbańczyk-Wochniak;A. Fernie
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文献类型：
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作者：
Agata Sienkiewicz-Porzucek;A. Nunes‐Nesi;Ronan Sulpice;J. Lisec;D. Centeno;P. Carillo;Andrea Leisse;Ewa Urbańczyk-Wochniak;A. Fernie
转基因番茄（Solanum lycopersicum）植物，表达的线粒体柠檬酸合酶基因的片段在反义方向和表现出温和的减少，这种酶的总细胞活性，显示基本上没有明显的表型改变从野生型。一个更详细的生理特性，然而，揭示了，虽然这些植物的特点是相对较少的变化，光合参数，它们显示通过三羧酸循环和呼吸速率增加的相对流量减少。此外，生化分析表明，转化体表现出相当大的改变代谢，其特征在于轻微的三羧酸循环，光合色素的有机酸的水平下降，并在一个单一的行中的蛋白质含量，但增加硝酸盐，几种氨基酸和淀粉的水平。我们还确定了最大的催化活性的主要代谢酶的范围广泛，进行有针对性的定量PCR分析柠檬酸合酶的所有三个亚型，并进行了更广泛的转录分析使用TOM 1微阵列。这些研究的结果证实，如果这些品系在硝酸盐同化方面受到一定程度的损害，它们不会受到严重影响，这表明存在重新编程代谢以弥补这种缺陷的策略。结果进行了讨论的背景下，碳-氮相互作用和interorganellar协调代谢。
Transgenic tomato (Solanum lycopersicum) plants, expressing a fragment of the mitochondrial citrate synthase gene in the antisense orientation and exhibiting mild reductions in the total cellular activity of this enzyme, displayed essentially no visible phenotypic alteration from the wild type. A more detailed physiological characterization, however, revealed that although these plants were characterized by relatively few changes in photosynthetic parameters they displayed a decreased relative flux through the tricarboxylic acid cycle and an increased rate of respiration. Furthermore, biochemical analyses revealed that the transformants exhibited considerably altered metabolism, being characterized by slight decreases in the levels of organic acids of the tricarboxylic acid cycle, photosynthetic pigments, and in a single line in protein content but increases in the levels of nitrate, several amino acids, and starch. We additionally determined the maximal catalytic activities of a wide range of enzymes of primary metabolism, performed targeted quantitative PCR analysis on all three isoforms of citrate synthase, and conducted a broader transcript profiling using the TOM1 microarray. Results from these studies confirmed that if the lines were somewhat impaired in nitrate assimilation, they were not severely affected by this, suggesting the presence of strategies by which metabolism is reprogrammed to compensate for this deficiency. The results are discussed in the context of carbon-nitrogen interaction and interorganellar coordination of metabolism.