Mapping local proteomic environments for lipid biosynthesis, trafficking, and compartmentation in plants

酰基脂是植物中含量最丰富的脂类，在食品、饲料和油脂化工等工业中有着重要的应用价值。例如，种子储存脂或种子油主要用作食用油，是世界上最重要的农产品之一。在加拿大，仅油菜籽每年就能产生299亿美元的经济价值。此外，酰基脂在植物发育中起着至关重要的作用，从形成细胞膜、储存能量到信号传导，对植物适应不利环境（如冷胁迫、病原体感染）至关重要。在植物中，脂质生物合成网络是高度区隔化的：新生脂肪酸在叶绿体中合成，酰基脂质组装在内质网和叶绿体中进行。因此，脂质生物合成依赖于亚细胞间广泛的脂质运输。脂质生物合成参与者的空间组织也对这一过程至关重要。我们最近的研究结果表明，脂质生物合成蛋白可能在内质网和叶绿体中形成相互作用体。然而，脂质如何在细胞器之间运输，并在空间上不同的相互作用组内输送，仍然是生物学中的一个关键问题。本研究旨在利用分子生物学、遗传学、生物化学和蛋白质组学等工具，解决我们在植物脂质转运和通道方面的基本知识空白。考虑到快速变化的气候和不断增长的人口，这些基本问题的答案对于未来合理设计植物和其他光合生物（如微藻）以提高石油产量和满足对食品、燃料和可再生材料日益增长的需求至关重要。在接下来的5年里，我建议首次使用接近标记和模式植物拟南芥来确定对植物脂质生物合成重要的亚细胞器室的完整蛋白质组，并确定在脂质运输和通道中的新蛋白质参与者。具体而言，本提案的三个主要目标包括：1)绘制参与脂质生物合成的细胞器亚域的局部蛋白质组，包括er -叶绿体膜接触位点和叶绿体膜间空间；2)绘制内质网和叶绿体中脂质生物合成相互作用组的局部蛋白质组；3)挖掘蛋白质组学数据，确定脂质生物合成中的新蛋白参与者，并表征顶级候选蛋白的功能。该研究将为我们对光合生物脂质转运和通道的机制理解做出重大贡献，建立有价值的公开可用的蛋白质组学数据库，并为未来合理设计作物以提高农业产量奠定基础。它还将为10名HQP提供出色的培训机会，他们将获得宝贵的技术和专业技能，为他们未来的职业生涯做好准备。

Acyl lipids are the most abundant lipids in plants and have highly valuable applications in food, feed and oleochemical industries. For example, seed storage lipids or seed oils are primarily used as edible oils and are among the most important agricultural commodities in the world. In Canada, canola alone generates $29.9 billion in economic value each year. Moreover, acyl lipids play essential roles in plant development, from forming cell membranes and storing energy to signaling, and are crucial for plant adaptation to adverse environments (e.g., cold stress, pathogen infection). In plants, the lipid biosynthetic network is highly compartmentalized: de novo fatty acids are synthesized in chloroplasts, and acyl lipid assembly occurs in the endoplasmic reticulum (ER) and chloroplasts. Thus, lipid biosynthesis relies on extensive lipid trafficking among subcellular compartments. Spatial organization of lipid biosynthetic players is also crucial for the process. As our recent findings suggest, lipid biosynthetic proteins may form interactomes in the ER and chloroplasts. However, how lipids are trafficked among organelles and channeled within spatially distinct interactomes remains a key question in biology. The proposed research aims to address fundamental gaps in our knowledge of plant lipid trafficking and channeling using the tools of molecular biology, genetics, biochemistry and proteomics. Given the rapidly changing climate and an ever-growing population, answers to these basic questions will be critical to the future rational design of plants and other photosynthetic organisms (e.g., microalgae) to enhance oil production and meet the growing demand for food, fuel and renewable materials. Over the next 5 years, I propose to determine, for the first time, the full proteomes of sub-organellar compartments that are important for plant lipid biosynthesis using proximity labeling and the model plant Arabidopsis, and to identify novel protein players in lipid trafficking and channeling. Specifically, the three main goals of this proposal include: 1) map local proteomes of organellar subdomains that are involved in lipid biosynthesis, including the ER-chloroplast membrane contact sites and chloroplast intermembrane spaces; 2) map local proteomes of lipid biosynthetic interactomes in the ER and chloroplasts; 3) mine proteomic data to identify novel protein players in lipid biosynthesis and characterize the function of top candidates. This research will make a significant contribution to our mechanistic understanding of lipid trafficking and channeling in photosynthetic organisms, establish valuable publicly-available proteomic databases, and lay the foundation for future efforts to rationally design crops to enhance agricultural production. It will also provide an outstanding training opportunity for 10 HQP who will gain valuable technical and professional skills that will prepare them for their future careers.