Dissection of general and specific regulatory mechanism of sulfur metabolism in Arabidopsis thaliana

拟南芥硫代谢一般和特异性调控机制的剖析

• 批准号: 235736350
• 负责人: Professor Dr. Rüdiger Hell
• 金额: --
• 依托单位: Centre for Organismal Studies (COS)
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2013
• 资助国家: 德国
• 起止时间: 2012-12-31 至 2023-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/235736350?language=en
• 关键词: Dissection; general; specific; regulatory; mechanism

Decrease of growth and translation is a general response of plants to diverse stresses as a trade-off to release energy for stress responses. This project addresses a fundamental question of plant research: How is protein translation and meristem activity regulated under mineral-nutrient deficiency? The coordination of these processes is crucial for acclimation responses such as shifts in shoot-to-root-ratio. In the previous proposal we investigated the sulfate assimilation pathway and its specific regulatory mechanisms in Arabidopsis thaliana. We focused on cysteine since it is the central metabolite that coordinates the assimilation of sulfur with that of carbon and nitrogen. The comparison of mutants that are either limited in flux of the sulfur or carbon/nitrogen branch of the pathway leading to cysteine revealed specific sensing mechanisms by the kinases GCN2 (general control non-derepressible 2) and TOR (target of rapamycin). We showed that both contribute independently to control of translation and growth of shoot and root and that plant TOR senses sulfur availability in leaves via down-regulation of glucose-TOR signaling. The TOR regulated network included induction of autophagy and down-regulation of translation and meristematic activity. These findings provide the basis to unravel the integration of different nutritional cues towards coordinated changes in plant growth regulation. The first part of this study we will address the specificity of TOR regulation upon limitation of diverse mineral nutrients. This will allow us to dissect the signals for the induction of the general response to nutrient limitation orchestrated by TOR from the signals controlling the sulfur deficiency specific response. Further emphasis will be given on the upstream signal transduction machinery for the sulfur deficiency-induced regulation of TOR. In the second part of the study we will unravel how TOR regulates downstream processes to achieve acclimation responses. Prime targets of TOR in this respect are the control of the plasticity of the proteome, the recycling of nutrients by autophagy and the ubiquitin/proteasome system, and the cell cycle in response to sulfur availability. Together, these approaches will explain TOR governed processes that are integral for the understanding of the sulfur regulatory network that can be seen as a role model for primary nutrient metabolism.

生长和翻译的减少是植物对各种压力的一般反应，作为释放压力反应能量的权衡。该项目解决了植物研究的基本问题：蛋白质翻译和分生组织活动如何在矿物质不足下调节？这些过程的协调对于适应响应（例如射击向根比的变化）至关重要。在先前的提案中，我们研究了拟南芥中硫酸盐同化途径及其特定的调节机制。我们专注于半胱氨酸，因为它是中央代谢产物与硫与碳和氮的同化。对途径的硫或碳/氮分支的限制的突变体的比较揭示了激酶GCN2（通用对照非耐耐压承重2）和TOR（Rapamycin的靶标）的特定感应机制。我们表明，两者都独立地控制了芽和根的翻译和生长，并且该植物通过下调葡萄糖信号传导感知叶子中的硫。 TOR调节的网络包括诱导自噬和翻译和分生活动的下调。这些发现为揭示了不同营养线索的整合，以与植物生长调节的协调变化相结合。本研究的第一部分，我们将在限制各种矿物营养物质的情况下解决TOR调节的特异性。这将使我们能够剖析信号，以诱导TOR从控制硫缺乏症的信号中精心策划的对营养限制的一般反应。将进一步重点放在硫缺乏引起的TOR调控的上游信号转导机械上。在研究的第二部分中，我们将解开TOR如何调节下游过程以实现适应反应。在这方面，TOR的主要目标是控制蛋白质组的可塑性，自噬和泛素/蛋白酶体系统对营养的回收，以及响应硫供应的细胞周期。这些方法将共同解释了对硫磺调节网络不可或缺的过程的控制过程，这些过程可以看作是主要营养代谢的榜样。