Identification and characterization of cell wall integrity monitoring components in plants

植物细胞壁的功能完整性必须保持，使它们能够在发育和防御生物和非生物胁迫期间发挥其功能。这种功能完整性受到细胞壁组成、结构和细胞代谢的影响。最近的研究表明，细胞壁损伤（CWD）损害了植物的功能完整性，并启动了特异性的代偿反应来维持完整性。这些反应包括细胞壁组成和结构的改变、植物激素的产生和碳水化合物的代谢。特别是对碳水化合物代谢的影响是敏感的操纵渗透。宿主实验室建立了以拟南芥苗木为基础的模型系统，研究CWD响应机制的作用方式。在这个奖学金的背景下，我的目标是执行两个子项目。首先，我将描述cwd诱导代偿反应所必需的基因功能。根据宿主实验室收集的转录和初步表型数据，一些候选基因已经与细胞壁代谢和对CWD的反应有关。我将确认这些初步结果，并将其具体扩展到详细的细胞壁分析和基因敲除中对细胞壁穿透真菌病原体的抗性的影响，以确定候选基因的生物学功能。第二个子项目将侧重于识别和表征CWD响应的早期信号组成部分。已经证明CWD诱导翻译后蛋白修饰。此外，假设拉伸激活的Ca2+通道MCA1是CWD反应的渗透敏感成分所必需的。因此，我将分析CWD和渗透支持对野生型和mca1幼苗磷酸化蛋白质组的影响，以确定响应CWD的翻译后修饰蛋白以渗透敏感的方式。然后，我将对候选基因使用敲除系来研究它们在CWD反应中的功能，特别是在碳水化合物分配中的功能。该项目的目标是将其定位于植物生理学、细胞生物学和植物病理学之间的交叉点，因此，关于细胞壁完整性维持机制的新见解将与这三个领域相关。在肿瘤依赖调控过程的新见解也将加强生物物理和生化研究之间的联系。

Functional integrity of plant cell walls has to be maintained enabling them to perform their functions during development and defence against biotic and abiotic stress. This functional integrity is influenced by cell wall composition, structure and cellular metabolism. Recent studies have shown that cell wall damage (CWD) impairing functional integrity is being detected in plants and specific compensatory reactions are initiated to maintain integrity. These reactions involve changes in cell wall composition and structure, in production of phytohormones and in carbohydrate metabolism. In particular the effects on carbohydrate metabolism are sensitive to manipulation by osmotica. The host lab has established an Arabidopsis seedling-based model system to study the mode of action of the CWD response mechanism. In the context of this fellowship I aim to execute two subprojects. First, I will characterize gene functions necessary for CWD-induced compensatory reactions. Based on transcriptional and preliminary phenotypic data collected in the host lab, several candidate genes have already been implicated in cell wall metabolism and the response to CWD. I will confirm these preliminary results and extend them specifically with respect to detailed cell wall analyses and the effect on resistance towards cell wall penetrating fungal pathogens in gene knockouts to determine biological functions of candidate genes. The second subproject will focus on the identification and characterization of early signalling components of the CWD response. It has already been shown that CWD induces post-translational protein modification. Furthermore, the putative stretch-activated Ca2+ channel MCA1 is required for the osmosensitive components of the CWD response. Therefore I will analyse the impact of CWD and osmotic support on the phosphoproteome of wild type and mca1 seedlings in order to identify proteins that are post-translationally modified in response to CWD in an osmosensitive way. I will then use knockout lines for the candidate genes to investigate their function in CWD response and particularly in carbohydrate partitioning. The aims of this project are locating it at the intersection between plant physiology, cell biology and phytopathology and therefore, novel insights regarding the cell wall integrity maintenance mechanism will be relevant for all three areas. New insights in turgor-dependent regulatory processes will also strengthen the link between biophysical and biochemical research.