Investigating Organelle Responses and Interactions in Plants

多细胞生物在压力下的生存依赖于其快速重建和维持细胞内稳态的能力。由于不受控制的人类活动正以极快的速度深刻地改变着我们的环境，因此我们有必要探索和了解不同生物体的压力缓解机制。考虑到它们在不同的栖息地成功地生存并继续繁殖，尽管有许多非生物和生物的压力，我选择了与植物一起工作。因此，我的长期研究计划旨在了解植物细胞的内稳态机制。我的实验室早期的nserc资助的项目已经对植物的快速亚细胞反应产生了新的见解，包括在感知环境变化的几秒钟内形成瞬时细胞器扩展。这些调查结果和迄今产生的工具为本建议提供了坚实的基础。在这里，我承认质体是亚细胞相互作用的中心，我关注于理解它们的行为和与其他细胞器的相互作用。提出了四个互补的调查领域。1. 研究酰基脂质在质体形态和行为快速变化中的作用：在植物中，质体是脂肪酸合成的主要部位，但酰基脂质向细胞其他部分分散的细胞生物学机制尚不清楚。我建议研究酰基-脂质通过质体包膜运输的作用，以获得对这一现象的见解。2. 阐明质体多形性和酰基/脂质代谢在应对非生物胁迫中的作用：众所周知，植物对胁迫的反应会诱导其酰基/脂质谱的变化。到目前为止，这一发现与质体形态和行为的改变无关。利用质体靶向荧光探针，我将研究酰基脂质和质体形态在逆境下的变化是否能为植物的逆境改良措施提供新的见解。3. 研究质体-内质网膜接触位点（MCS）作为脂质运输通道的作用：这一新的研究领域将为质体和内质网之间MCS的形成提供见解，以促进双向酰基-脂质运输。4. 了解细胞器延伸在细胞内稳态中的一般作用：活的植物细胞零星地从几个细胞器（包括质体）中表现出管状延伸，但其意义尚不清楚。利用几种双转基因和三重转基因，并将研究范围扩大到脂滴，我建议研究细胞器扩展在维持体内平衡中的作用。该提案主要依赖于活细胞成像、生物化学和脂质组学。除了为HQP在分子和细胞生物学技术方面的培训创造大量机会外，还将提供有关活植物细胞的宝贵见解，这将导致高质量的研究出版物和公众教育。

A multicellular organism's survival following stress relies on its ability to quickly re-establish and maintain homeostasis in its cells. Since uncontrolled human activity is profoundly altering our environment at a rapid pace it is imperative that we explore and learn about stress alleviation mechanisms in different organisms. Considering their success in surviving and continuing to proliferate in diverse habitats despite numerous abiotic and biotic stresses I have chosen to work with plants. Thus, my long--term research program aims at understanding homeostasis mechanisms in plant cells. Earlier NSERC-funded projects to my lab have resulted in new insights on the rapid sub-cellular responses in plants, including the formation of transient organelle extensions, within seconds of sensing a change in the environment. These findings and the tools generated so far provide a firm basis for the present proposal. Here, acknowledging the plastids as subcellular interaction hubs I focus on understanding their behaviour and interactions with other organelles. Four complementary areas of investigation are proposed. 1. Investigating the role of acyl-lipids on rapid changes in plastid morphology and behaviour: Plastids form the major site of de novo fatty acid synthesis in plants but the cell biological mechanisms involved in acyl-lipid dispersal to the rest of the cell are not understood. I propose to investigate the role of acyl-lipid traffic through the plastid envelope membranes to achieve insights on the phenomenon. 2. Elucidating the role of plastid pleomorphy and acyl/lipid metabolism in response to abiotic stress: It is well known that plant response to stress induces changes in its acyl-lipid profile. So far this finding is not associated with alterations in plastid morphology and behaviour.Using plastid--targeted fluorescent probes I will investigate whether changes in acyl-lipid and plastid morphology in response to stress can provide new insights on stress amelioration measures in plants. 3. Investigating the role of plastid--ER membrane contact sites (MCS) as conduits for lipid trafficking: This new area of investigation will provide insights on MCS formation between plastids and the ER for facilitating bidirectional acyl-lipid traffic. 4. Understanding the general role of organelle extensions in cellular homeostasis: Living plant cells exhibit tubular extensions sporadically from several organelles, including plastids but their significance is not known. Using several double and triple transgenics and extending the investigation to lipid droplets I propose to investigate the role of organelle extensions in maintaining homeostasis. The proposal relies heavily on live--cell imaging, biochemistry and lipidomics. Besides creating considerable opportunities for HQP training in molecular and cellular biology techniques, providing valuable insights on the living plant cell it will lead to high quality research publications and public education.