EAGER: Uncovering Mechanistic Link Between Autophagy and Circadian Clock in Arabidopsis

在白天，植物利用光合作用产生的碳水化合物来支持它们的生长和发育。为了避免在夜间无法进行光合作用时挨饿，植物将白天产生的一些碳水化合物储存起来，作为淀粉储备供夜间使用。在拟南芥植物中，95%的储存淀粉在黎明前被消耗。有趣的是，24小时的生物钟控制着淀粉降解的速度，因此无论夜晚的长度如何，黎明前都会使用适量的淀粉。钟控夜间淀粉使用所涉及的确切分子过程尚不清楚。最近，自噬(自噬)过程被认为与夜间淀粉降解有关。这个项目将以拟南芥植物为模型系统，研究时钟和自噬之间的相互关系。这些研究的结果应该提供通过维持适当的昼夜能量平衡来提高植物生产力的策略，特别是在环境条件变化期间。通过其更广泛的影响，该项目将从生物学本科生计划(BUSP)培养一名研究科学家、一名博士后研究员和一名本科生。自噬是一个动态的过程，在这个过程中，双膜结合的囊泡被称为自噬小体，包裹细胞质材料，并将它们靶向液泡/溶酶体，以进行降解或循环。自噬(autophagy，ATG)核心蛋白在包括拟南芥模式植物在内的真核生物中是保守的。泛素样修饰物Atg8在自噬小体的生物发生、货物募集和自噬运送到液泡/溶酶体中起着关键作用。拟南芥Atg8相互作用研究揭示了一个有趣的模块，它由拟南芥昼夜节律时钟组成。该项目将研究拟南芥自噬和生物钟之间可能的分子联系。该项目将专门研究生物钟是否调节自噬，以及自噬是否反过来调节拟南芥的生物钟功能。了解自噬和昼夜节律系统之间的机制联系将有助于深入了解植物的碳同化和能量动态平衡。

During the daytime plants use carbohydrate generated through photosynthesis to support their growth and development. To avoid starving in the night when photosynthesis is not possible, plants store some of the carbohydrate produced in the day as starch reserve for nighttime use. In Arabidopsis plants, 95% of the stored starch is consumed by dawn. Interestingly, the 24-hour circadian clock controls the rate of starch degradation so that the appropriate amount of starch is used by dawn irrespective of the length of the night. The precise molecular processes involved in clock-controlled nighttime starch usage are not understood. Recently, the autophagy (self-eating) process has been implicated in nighttime starch degradation. This project will investigate the inter-relationship between the clock and autophagy using the Arabidopsis plant as the model system. Results from these studies should provide strategies to improve plant productivity by maintaining the appropriate day-night energy balance especially during changes in environmental conditions. Through its broader impacts, project will train a research scientist, a post-doctoral fellow, and an undergraduate student from Biology Undergraduate Scholars Program (BUSP). Autophagy is a dynamic process during which double membrane-bound vesicles called autophagosomes enclose cytoplasmic materials and target them to the vacuole/lysosome for degradation or recycling. Autophagy (Atg) core proteins are conserved among eukaryotes including Arabidopsis model plant. The ubiquitin-like modifier Atg8 plays a key role in autophagosome biogenesis, cargo recruitment, and autophagosme delivery to the vacuole/lysosome. Arabidopsis Atg8 interaction studies uncovered an intriguing module consisting of Arabidopsis circadian clock components. This project will investigate the possible molecular link between Arabidopsis autophagy and the circadian clock. The project will specifically investigate whether circadian clock regulates autophagy and whether autophagy in turn regulates clock function in Arabidopsis. Understanding the mechanistic link between autophagy and circadian system should provide insights on carbon assimilation and energy homeostasis in plants.