Regulation of pathogen defence by plant cell wall integrity signalling

细胞壁对于植物的生长、发育和抗逆性具有根本的重要性。细胞壁结构的功能要求根据当前的发展和环境状况而不同。细胞壁完整性（CWI）由质膜定位蛋白监测，当完整性受损时，诱导下游反应以允许细胞壁适应。这些反应与细胞代谢和信号网络相协调，例如在病原体感染期间。先前的工作表明，拟南芥中的CWI信号是由植物诱导肽（PEP）调节的，这可能介导CWI和防御信号通路之间的串扰。在这个项目的第一部分，我们将（i）确定PEP检测所需的分子组分细胞壁损伤和（ii）调查的压力依赖性变化的作用，在本地化和加工的PEP前肽。在本项目的第二部分，我们将研究CWI损伤后防御反应的激活和调节。初步证据表明，植物抗毒素的积累是由细胞壁损伤引发的，并受PEP的调节。为了进一步阐明CWI和PEP信号通路之间的串扰及其对病原体防御的影响，我们将（i）研究受体激酶THESEUS 1和激发肽PEP 3在这一过程中的贡献，（ii）鉴定CWI和PEP信号通路之间串扰所需的基因，以及（iii）分析CWI依赖的防御反应对穿透细胞壁的植物病原真菌Colletotrichum higginsianum的效力。该项目将利用遗传，细胞生物学和生理学方法，以获得对非生物/细胞壁和生物应激信号传导的协调的新见解，并确定这些信号传导途径对病原体感染结果的影响。

Cell walls are of fundamental importance for the growth, development and stress resistance of plants. The functional requirements of the cell wall structure differ depending on the current developmental and environmental situation. Cell wall integrity (CWI) is monitored by plasma membrane-localised proteins that, when integrity is compromised, induce downstream responses to allow cell wall adaptation. These responses are coordinated with cellular metabolism and signalling networks, for example during pathogen infection. Previous work has shown that CWI signalling in Arabidopsis thaliana is regulated by plant elicitor peptides (PEPs), which may mediate a crosstalk between CWI and defence signalling pathways. In the first part of this project, we will (i) identify molecular components required for PEP detection upon cell wall damage and (ii) investigate the role of stress-dependent changes in localisation and processing of PEP propeptides. In the second part of the project, we will investigate the activation and regulation of defence responses upon CWI impairment. Preliminary evidence indicates that the accumulation of phytoalexins is triggered by cell wall damage and regulated by PEPs. To further elucidate the crosstalk between CWI and PEP signalling pathways and characterise its impact on pathogen defence, we will (i) investigate the contributions of the receptor kinase THESEUS1 and the elicitor peptide PEP3 in this process, (ii) identify genes required for crosstalk between CWI and PEP signalling pathways, and (iii) analyse the efficacy of CWI-dependent defence responses against the cell wall-penetrating phytopathogenic fungus Colletotrichum higginsianum.This project will use genetic, cell biological and physiological methods to gain new insights into the coordination of abiotic/cell wall and biotic stress signalling and determine the impact of these signalling pathways on the outcome of pathogen infections.