Regulation of pathogen defence by plant cell wall integrity signalling

细胞壁对植物的生长发育和抗逆性具有重要意义。细胞壁结构的功能要求根据当前的发展和环境情况而有所不同。细胞壁完整性(CWI)是由质膜定位的蛋白质监测的，当完整性受到损害时，这些蛋白质会诱导下游反应，从而允许细胞壁适应。这些反应与细胞新陈代谢和信号网络相协调，例如在病原体感染期间。以前的工作表明，拟南芥中的CWI信号受植物激发子多肽(PEP)的调控，植物激发子多肽可能在CWI和防御信号通路之间介导串扰。在这个项目的第一部分，我们将(I)确定PEP在细胞壁损伤时检测所需的分子成分，并(Ii)研究压力依赖的变化在PEP前肽的定位和加工中的作用。在项目的第二部分，我们将研究CWI损伤时防御反应的激活和调节。初步证据表明，植物保卫素的积累是由细胞壁损伤触发的，并受PEPS的调节。为了进一步阐明CWI和PEP信号通路之间的串扰并表征其对病原体防御的影响，我们将(I)研究受体激酶THESEUS1和激发子多肽PEP3在这一过程中的作用，(Ii)识别CWI和PEP信号通路之间串扰所需的基因，以及(Iii)分析依赖CWI的防御反应对穿透细胞壁的植物病原菌Colletotrichum higgisianum的有效性。本项目将使用遗传学、细胞生物学和生理学方法对非生物/细胞壁和生物胁迫信号的协调获得新的见解，并确定这些信号通路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.