The impact of short-cutting photorespiration on carbon and nitrogen metabolism

短程光呼吸对碳氮代谢的影响

• 批准号: 134777978
• 负责人: Professorin Dr. Veronica Maurino
• 金额: --
• 依托单位: Abteilung Molekulare Pflanzenphysiologie
• 依托单位国家: 德国
• 项目类别: Research Units
• 财政年份: 2009
• 资助国家: 德国
• 起止时间: 2008-12-31 至 2016-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/134777978?language=en
• 关键词: impact; short; cutting; photorespiration; carbon

We recently produced Arabidopsis plants engineered to oxidise glycolate inside the plastids. These plants showed beneficial effects on growth and had higher CO2 assimilation rates per unit area and chlorophyll. To achieve this, it was of radical importance to introduce catalase in the plastids to eliminate H2O2 produced by glycolate oxidase. Here, we propose to work further in the optimization of this original pathway using a glycolate dehydrogenase (GlcDH), without production of H2O2. To this end, we will follow two strategies, (i) the use of Micromonas GlcDH and (ii) the combined use of Synechocystis GlcD1 and GlcD2. Transgenic lines bearing the new pathways will be selected and the impact on plant performance will be analysed at different levels. Moreover, the kinetic properties of these activities enzymes will be thoroughly investigated. On the other hand, photorespiration has been clearly demonstrated to interact with other cellular processes. In this regard, our previous work indicated a light-dependent accumulation of 2-hydroxyglutarate (2HG) in the shm1-1 mutant, which was correlated with high levels of glycine, 2-ketoglutarate and many amino acids. Moreover, we showed for the first time that both enantiomeric forms of 2HG, D-and L-2HG can be found, although at extremely low levels, in wild-type leaf extracts of plants growing in normal conditions. Our group will thus specifically focus on the cross-talk of photorespiration with processes involving 2HG (e.g. senescence, metabolic repair). For this purpose a combination of genomic, biochemical, metabolomic and flux profiling approaches will be applied to a set of photorespiratory mutants, which accumulate glycine to different levels.

最近，我们生产了拟南芥植物，这些植物在质体内部氧化乙醇酸。这些植物对生长显示出有益的影响，并且每单位面积和叶绿素的二氧化碳同化速率较高。为了实现这一目标，在质体中引入过氧化氢酶以消除乙醇酸氧化酶产生的H2O2至关重要。在这里，我们建议使用乙醇酸脱氢酶（GLCDH）进一步优化该原始途径，而无需产生H2O2。为此，我们将遵循两种策略，（i）使用Micromonas glcdh和（ii）Synechocystis glcd1和glcd2的联合使用。将选择带有新途径的转基因线，并将在不同级别分析对植物性能的影响。此外，将彻底研究这些活性酶的动力学特性。另一方面，已经清楚地证明了光呼吸与其他细胞过程相互作用。在这方面，我们以前的工作表明，SHM1-1突变体中2-羟基戊二酸（2HG）的光依赖性积累，该突变体与高甘氨酸，2-酮戊二酸和许多氨基酸的高水平相关。此外，我们首次表明，在正常条件下生长的野生型植物提取物中，在极低的水平下，可以找到两种对映体形式的2Hg，D和L-2HG。因此，我们的小组将专门针对涉及2HG的过程（例如衰老，代谢修复）的光呼吸的串扰。为此，将将基因组，生化，代谢组和通量分析方法的组合应用于一组光呼吸突变体，这些突变体将甘氨酸累积到不同的水平。