Molecular, regulatory and functional properties of key enzymes of plant carbohydrate and phosphate metabolism

我的长期研究目标是确定植物碳水化合物和磷酸盐（Pi）代谢关键酶的分子，调节和功能特性。我们的详细的纯化酶的生化特性最近增加了各种创新的蛋白质组学和基因组学工具，导致在几个迷人的发现有关的控制磷酸烯醇式丙酮酸（PEP）代谢在发育中的蓖麻油种子，和生化适应Pi-剥夺（-Pi）拟南芥中的丰富的甜菜碱胚乳。PEP羧化酶（PEP carboxylase，PEPC）是一种重要的、多方面的变构酶，位于植物初级代谢的核心，参与控制种子碳水化合物分配到具有重要农业意义的终产物如贮藏油和蛋白质中，同时也帮助植物科普次优的Pi，这是许多土壤中最难获得的常量营养素之一。拟议的研究重点是：（A）发育中的油料种子的新型1类和2类PEPC同工型的功能特性、蛋白质相互作用和亚细胞定位，&（B）PEPC同工酶的特性和Pi-清除功能，所述PEPC同工酶被-Pi拟南芥可逆地积累和磷酸化。（假设导致由-Pi植物的根分泌溶解Pi的有机酸），以及主要的胞内和胞外紫色酸性磷酸酶同工酶上调-Pi拟南芥（假设有助于从细胞内和土壤定位的Pi-酯中回收Pi）。我们的研究对加拿大农业中的问题有重要的应用，包括：（i）有针对性地修改储存油与油菜或大豆等油籽中的蛋白质水平，（ii）开发Pi高效的转基因作物，迫切需要减少人类对不可再生，不可持续和污染的Pi肥料的猖獗但低效的使用。在此期间，我们将继续整合新的蛋白质组学和基因组学工具到我们的研究。这些创新需要重组，培训和优化，但提供了我们可以收集的数据类型的定量进步，并为现代植物代谢生物化学的HQP培训奠定了坚实的基础。

My long-term research goal is to identify the molecular, regulatory, and functional properties of key enzymes of plant carbohydrate and phosphate (Pi) metabolism. Our detailed biochemical characterization of purified enzymes was recently augmented by various innovative proteomic and genomic tools, resulting in several fascinating discoveries concerning the control of phosphoenolpyruvate (PEP) metabolism in the triglyceride-rich endosperm of developing castor oilseeds, and the biochemical adaptations of Pi-deprived (-Pi) Arabidopsis thaliana. PEP carboxylase (PEPC) is an important and 'multi-faceted' allosteric enzyme situated at the core of primary plant metabolism that participates in the control of seed carbohydrate partitioning to agronomically important end-products such as storage oils and proteins, but also helps plants to cope with suboptimal Pi, one of the least available macronutrients in many soils. Proposed research is focused on the: (A) functional properties, protein interactions, and subcellular localization of novel Class-1 & Class-2 PEPC isoforms of developing oilseeds, & (B) properties and Pi-scavenging functions of a PEPC isozyme that is reversibly accumulated and phosphorylated by -Pi Arabidopsis (hypothesized to result in excretion of Pi-solubilizing organic acids by roots of -Pi plants), as well as the predominant intra- & extracellular purple acid phosphatase isozymes upregulated by -Pi Arabidopsis (hypothesized to help recycle Pi from intracellular and soil-localized Pi-esters). Our studies have significant applications to problems in Canadian agriculture including the: (i) targeted modification of storage oil vs. protein levels in oilseeds such as canola or soybean, & (ii) development of Pi-efficient transgenic crops, urgently needed to reduce mankind's rampant but inefficient use of non-renewable, unsustainable, and polluting Pi fertilizers. During this granting period we will continue to integrate new proteomic and genomic tools into our research. These innovations require retooling, training, and optimization, but provide quantitative advances in the types of data that we can gather, and a solid foundation for HQP training in modern plant metabolic biochemistry.