Mechanisms and functions of SNARE protein-dependent and vesicle-mediated exocytosis in plant immune responses

植物对病原微生物的细胞外免疫反应是一种普遍存在的现象。我们结合遗传和生物化学的研究表明，存在至少三种分子机制，限制微生物在质外体的生长。这些包括囊泡介导的未知货物的胞吐作用，通过ABC转运蛋白转运吲哚芥子油苷衍生的代谢物，以及外泌体的生物发生/递送。在这个项目中，我们研究了囊泡介导的免疫反应，需要质膜驻留PEN 1 syntaxin，衔接蛋白SNAP 33和囊泡驻留VAMP 721/722之间形成三元SNARE复合物。我们最近的观察表明，这种分泌途径是迅速激活的细菌PAMPs的反应，并有助于细菌的生长限制。这一点和最近的进展，在质谱法分泌的分子，可以确定在根分泌物中，提供了系统分析货物的基础。此外，我们将进行细胞生物学和生化实验，以更好地了解VAMP 721/722内膜隔室在植物防御反应中的性质和动态。

Extracellular immune responses to microbial pathogens are a widespread phenomenon in plants. Our combined genetic and biochemical studies revealed the existence of at least three molecular mechanisms that restrict microbial growth in the apoplast. These include vesicle-mediated exocytosis of unknown cargo, transport of indole glucosinolate-derived metabolites through an ABC transporter, and the biogenesis/delivery of exosomes. In this project we study vesicle-mediated immune responses requiring ternary SNARE complex formation between plasma membraneresident PEN1 syntaxin, the adaptor protein SNAP33, and vesicle-resident VAMP721/722. Our recent observations show that this secretory pathway is rapidly activated in response to bacterial PAMPs and contributes to bacterial growth restriction. This and recent advances in mass spectrometry by which secreted molecules can be identified in root exudates, provide the basis for systematic analysis of cargo. In addition, we will perform cell biological and biochemical experiments to better understand the nature and dynamics of VAMP721/722 endomembrane compartments in plant defense responses.