Sensing and retrograde signaling of mitochondrial metabolic states in plants

植物的自养和无根性对其代谢提出了独特的要求，因此植物的代谢网络是所有生物中最复杂的。为了适应经常快速变化的环境条件，代谢网络的能力必须动态调整和“重新布线”，以一种量身定制的方式，在任何给定的时刻满足细胞的能量和代谢需求。植物线粒体在细胞代谢中起着关键作用，为细胞提供ATP、还原力、碳中间体和各种其他重要代谢物。线粒体蛋白质组的动态调整需要信号来感知细胞器的状态并将其传达回细胞核。这被称为逆行信号。在植物中，由于来自其他细胞器（如质体）的逆行信号的出现，对逆行信号的解释变得更加复杂。因此，信号识别的特异性是一个先决条件。本项目旨在研究与线粒体逆行信号有关的细胞特异性代谢物识别的进化保守过程。自己的研究结果表明，三羧酸循环活动的改变导致的细胞有机酸水平浓度的扰动对核基因表达有重大影响。该项目的目的是调查和剖析这种线粒体逆行信号通路，以确定潜在的调节机制和成分（基因，蛋白质和代谢物）。选择解决这个问题的方法是基于最先进的遗传和生化技术，包括表达和启动子分析，前向遗传筛选，转录后修饰分析以及鉴定新的代谢物结合蛋白和信号代谢物。

The autotrophic and sessile nature of plants imposes unique demands on their metabolism, and consequently the metabolic network of plants is among the most complex of any organism. To adapt to often rapidily changing environmental conditions the capacity of the metabolic network has to be dynamically adjusted and ‘rewired’ in a way that it is tailored to meet exactly the energy and metabolic demands of the cell at any given moment in time. Plant mitochondria are key players in the cellular metabolism providing the cell with ATP, reducing-power, carbon intermediates and various other important metabolites. The dynamic adjustments of the mitochondrial proteome require signals that sense the status of the organelle and communicate it back to the nucleus. This is referred to as retrograde signaling. In the case of plants, the interpretation of retrograde signals is further complicated by the occurrence of retrograde signals from other organelles such as the plastid. Thus, specificity in signal recognition is a prerequisite. This project aims to investigate the evolutionary conserved process of cell-specific recognition of metabolites in connection with mitochondrial retrograde signaling. Own results demonstrate that perturbations in cellular concentrations of organic acid levels resulting from alterations in tricarboxylic acid cycle activities have a major impact on nuclear gene expression. The aim of this project is to investigate and dissect this mitochondrial retrograde signaling pathway to identify the underlying regulatory mechanisms and components (genes, proteins and metabolites). The approach chosen to tackle this question is based on state of the art genetic and biochemical techniques including expression- and promoter analysis, a forward-genetic screen, the analysis of posttranscriptional modifications and the identification of novel metabolite-binding proteins and signal metabolites.