Investigating Organelle Responses and Interactions in Plants

多细胞生物体在应激后的生存依赖于其快速重建和维持细胞内的动态平衡的能力。由于不受控制的人类活动正在以快速的速度深刻地改变我们的环境，我们必须探索和了解不同生物体的压力缓解机制。考虑到它们成功地在不同的栖息地生存并继续繁殖，尽管面临着无数的非生物和生物压力，我选择了与植物合作。因此，我的长期研究计划旨在了解植物细胞的动态平衡机制。早些时候，NSERC资助的我的实验室项目已经对植物中快速的亚细胞反应产生了新的见解，包括在感知到环境变化的几秒钟内形成瞬时细胞器延伸。这些调查结果和迄今产生的工具为本提案提供了坚实的基础。在这里，我承认叶绿体是亚细胞相互作用的中心，我专注于了解它们的行为以及与其他细胞器的相互作用。提出了四个相辅相成的调查领域。1.研究了脂酰脂在叶绿体形态和行为快速变化中的作用：叶绿体是植物从头合成脂肪酸的主要场所，但脂酰脂扩散到细胞其他部分的细胞生物学机制尚不清楚。我建议研究通过叶绿体被膜的脂酰化运输的作用，以实现对这一现象的深入了解。2.阐明叶绿体多态和酰基/脂代谢在响应非生物胁迫中的作用：众所周知，植物对逆境的响应会导致其酰基脂的变化。到目前为止，这一发现与叶绿体形态和行为的变化没有关联。使用叶绿体靶标荧光探针，我将调查在胁迫响应下，脂酰脂和叶绿体形态的变化是否可以为植物的逆境缓解措施提供新的见解。3.研究叶绿体-内质网膜接触位点(MCS)作为脂类运输管道的作用：这一新的研究领域将为叶绿体和内质网之间MCS的形成提供新的见解，以促进酰基-脂类的双向运输。4.了解细胞器伸展在细胞内稳态中的一般作用：活的植物细胞零星地表现出来自几个细胞器的管状伸展，包括叶绿体，但其意义尚不清楚。使用几种双重和三重转基因，并将研究扩展到脂滴，我建议调查细胞器延伸在维持内环境稳定中的作用。该提案在很大程度上依赖于活细胞成像、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相当大的机会，提供关于活植物细胞的有价值的见解外，它还将导致高质量的研究出版物和公共教育。

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.