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、饲料和油脂化学工业中具有很高的应用价值。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，仅油菜籽一项每年就产生299亿美元的经济价值。此外，酰基类脂在植物发育中发挥着重要作用，从形成细胞膜、储存能量到信号转导，对于植物适应不利环境(例如，冷胁迫、病原体感染)是至关重要的。在植物中，脂类生物合成网络是高度区域化的：从头合成的脂肪酸在叶绿体中合成，酰基脂类的组装发生在内质网(ER)和叶绿体中。因此，脂类的生物合成依赖于亚细胞间广泛的脂类运输。脂质生物合成玩家的空间组织对这一过程也是至关重要的。我们最近的发现表明，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。然而，脂类如何在细胞器之间进行交易，并在空间上不同的相互作用中进行输送，仍然是生物学中的一个关键问题。这项拟议的研究旨在利用分子生物学、遗传学、生物化学和蛋白质组学的工具，解决我们在植物脂肪运输和传导方面的基本知识空白。鉴于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作用有机体(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，我建议第一次利用邻近标记和模式植物拟南芥来确定亚细胞器隔室的完整蛋白质组，这些蛋白质组对植物脂类的生物合成是重要的，并确定在脂运输和通道中新的蛋白质角色。具体地说，该建议的三个主要目标包括：1)定位参与脂类生物合成的细胞器亚域的局部蛋白质组，包括内质网-叶绿体膜接触部位和叶绿体膜间隙；2)定位内质网和叶绿体中脂类生物合成相互作用的局部蛋白质组；3)挖掘蛋白质组数据，以发现脂类生物合成中的新蛋白质成员，并表征顶级候选蛋白的功能。这项研究将对我们从机理上理解光合作用生物体内的脂类运输和通道做出重大贡献，建立有价值的公开可用的蛋白质组数据库，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提供一个绝佳的培训机会，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.