Metabolic control of plant non-photosynthetic metabolism

非光合代谢在植物生物学中发挥着重要作用。糖酵解降解来自光合作用的糖并供给细胞呼吸以产生代谢能量。糖酵解和呼吸作用也产生碳分子，作为各种植物生物合成途径的前体。植物还利用糖酵解和呼吸代谢来适应各种生物和非生物胁迫。随着世界人口的稳步增长，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恶化，这种情况可能会加剧。 通过基因工程对植物代谢进行合理改造是产生适应人类未来需求的新农业品种的解决方案。然而，使用这种策略需要很好地理解非光合代谢及其调节。我的研究团队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于S-谷胱甘肽化，S-谷胱甘肽化是三肽谷胱甘肽对蛋白质半胱氨酸巯基残基的稳定修饰，其可以调节酶活性。氧化胁迫是生物和非生物胁迫的常见结果，促进S-谷胱甘肽化。它通常也靶向光合细胞中的碳水化合物代谢酶。我实验室的HQP将鉴定拟南芥非光合细胞培养物和暴露于氧化应激的根中的S-谷胱甘肽化蛋白。他们还将致力于鉴定和表征参与脱谷胱甘肽化的酶，即从修饰的蛋白质中去除谷胱甘肽。他们将进一步研究植物糖酵解和能量代谢中特定酶的调节，这些酶是S-谷胱甘肽化的目标。拟议研究的另一部分涉及核苷二磷酸激酶（NDPKs）的表征。后者是多功能酶，被鉴定为人类转移抑制因子。我们最近的工作NDPK 1，细胞溶质植物NDPK异构体表明，这种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起着重要的作用。我们将通过研究NDPK 1作为蛋白激酶的活性来继续我们对NDPK 1的表征。我们还将开始研究最近发现的NDPK，定位于内质网的puerectin。 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，这项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.