Metabolic control of plant non-photosynthetic metabolism

非光合代谢在植物生物学中起着重要的作用。糖酵解降解光合作用产生的糖，并为细胞呼吸提供能量以产生代谢能量。糖酵解和呼吸也产生碳分子，作为各种植物生物合成途径的前体。植物也利用糖酵解和呼吸代谢来适应各种生物和非生物胁迫。在世界人口稳步增长的同时，对农业资源，特别是农作物的需求也在增加。随着即将到来的气候变化危机预计将造成世界许多地区农业生产力的恶化，这种情况可能会加剧。通过基因工程对植物代谢进行基本改造是产生适应人类未来需求的新农业品种的一种解决方案。然而，使用这种策略需要对非光合代谢及其调控有很好的了解。我的研究小组通过研究糖和能量代谢中酶的调节来解决这个问题。本提案中描述的研究的一个方面将集中在s -谷胱甘肽化上，这是一种由三肽谷胱甘肽对蛋白质半胱氨酸硫醇残基的稳定修饰，可以调节酶的活性。氧化应激促进s -谷胱甘肽化，这是生物和非生物应激的常见后果。它也通常针对光合细胞中碳水化合物代谢的酶。我实验室的HQPs将在拟南芥非光合细胞培养物和氧化应激根中识别s -谷胱甘肽化蛋白。他们还将致力于识别和表征参与去谷胱甘肽化的酶，即从修饰蛋白中去除谷胱甘肽的酶。他们将进一步研究s -谷胱甘肽化对植物糖酵解和能量代谢中特定酶的调节作用。拟议研究的另一部分涉及核苷二磷酸激酶（NDPKs）的表征。后者是在人类中被鉴定为转移抑制因子的多功能酶。我们最近对细胞质植物NDPK异构体NDPK1的研究表明，该酶在控制代谢能量和调节淀粉和纤维素合成途径之间的碳通量方面起着重要作用。我们将通过研究NDPK1作为蛋白激酶的活性来继续表征NDPK1。我们还将开始研究最近发现的NDPK，推测定位于内质网。它的亚细胞定位、调节和可能的代谢功能将被表征。从长远来看，该研究将为未来作物品种的预测代谢建模和代谢工程提供重要信息。

Non-photosynthetic metabolism fulfills important functions in plant biology. Glycolysis degrades sugars derived from photosynthesis and feeds cellular respiration to generate metabolic energy. Glycolysis and respiration also generate carbon molecules that serve as precursors for various plant biosynthetic pathways. Plants also use glycolytic and respiratory metabolisms to adapt to various biotic and abiotic stresses. While the world population is steadily growing, there is an increased need for agricultural resources, and in particular, crop plants. This situation will likely exacerbate with the impending climate change crisis expected to create a deterioration of agricultural productivity in many areas of the world. The rationale modification of plant metabolism by genetic engineering is a solution to generate new agricultural varieties adapted for the future needs of the human population. The use of this strategy nevertheless requires a good understanding of nonphotosynthetic metabolism and its regulation. My research team addresses this problem by studying the regulation of enzymes in sugar and energy metabolism. One aspect of the research described in this proposal will focus on S-glutathionylation, a stable modification of protein cysteine thiol residues by the tripeptide glutathione, which can regulate enzyme activity. S-glutathionylation is promoted by oxidative stress, a frequent consequence of biotic and abiotic stresses. It also commonly targets enzymes of carbohydrate metabolism in photosynthetic cells. HQPs in my laboratory will identify S-glutathionylated proteins in Arabidopsis thaliana non-photosynthetic cell cultures and roots exposed to oxidative stress. They will also aim to identify and characterize the enzymes(s) that are involved in deglutathionylation, the removal of glutathione from a modified protein. They will furthermore study the regulation of specific enzymes in plant glycolysis and energy metabolism, which are targeted by S-glutathionylation. Another part of the proposed research concerns the characterization of nucleoside diphosphate kinases (NDPKs). The latter are multifunctional enzymes identified as metastasis suppressors in humans. Our recent work on NDPK1, the cytosolic plant NDPK isoform indicate that this enzyme plays an important role in the control of metabolic energy and the regulation of carbon fluxes between the starch and cellulose synthesis pathways. We will continue our characterization of NDPK1 by investigating its activity as a protein kinase. We will also initiate the study of a recently discovered NDPK, putatively localized in the endoplasmic reticulum. Its subcellular localization, regulation, and possible metabolic function will be characterized. In the long term, this research should provide crucial information for predictive metabolic modelization and metabolic engineering of future crop varieties.