Cross-kingdom RNA communication during smut fungal infection by Thecaphora thlaspeos

在感染期间，病原体与宿主沟通，以抑制植物免疫系统，改变植物新陈代谢。虽然在经典的观点中，蛋白质效应器是主要参与者，但最近变得明显的是，RNA也是交换的，并有助于跨王国的交流。一种拟议的传递机制是在细胞外小泡(EV)中运输，这些EV从病原体转移到宿主细胞以传递它们的货物。遗传上易驯化的黑粉菌是研究EV介导的跨王国RNA通讯的理想系统。在EVS中的mRNA转运的开创性工作是在模式黑粉菌Ustilago maydis中进行的。在这个建议中，我们关注的是十字花科黑粉菌T.thlasPeos中的跨王国RNA通讯，这是我们最近建立的一种模式植物拟南芥的遗传易感性病原菌。我们将首先提供EV货物的清单，以随后解决跨王国RNAi和EV介导的mRNA运输与毒力的功能相关性。与玉米粉虱不同的是，T.thlaspos保留了RNAi机制，因此我们将通过比较的方法来确定mRNA和SRNA易位对感染的相对贡献。电动汽车的核心货物是什么？MRNAs和sRNA针对的是相同的植物过程吗？在RU5116，exRNA通讯的框架内，T.thlasPeos将呈现黑粉病病原菌，因为它能够利用sRNA和mRNAs进行跨域通讯。我们将特别将RNA效应物与维管根病原体、互助体和常年感染期间的病原体进行比较。因此，我们将对RNA效应器在植物-微生物相互作用中的功能作用有详细的了解。在未来，阐明EV载量的分子机制将对了解RNAs如何在病原体中作为易位和翻译的靶点将是重要的。

During infections, pathogens communicate with their host to supress the plant immune system and modify plant metabolism. While in the classical view, protein effectors are the main player, recently it has become apparent that also RNAs are exchanged and contribute to cross-kingdom communication. A proposed delivery mechanism is the transport in extracellular vesicles (EVs) that translocate from the pathogen to the host cell to deliver their cargo. The genetically tractable smut fungi are ideal systems to study EV-mediated cross-kingdom RNA communication. Pioneering work on mRNA transport in EVs is carried out in the model smut fungus Ustilago maydis. In this proposal, we focus on cross-kingdom RNA communication in the Brassicaceae smut fungus T. thlaspeos, which we have recently established as a genetically tractable pathogen of the model plant Arabidopsis thaliana. We will first provide an inventory of the EV cargo to subsequently address the functional relevance of cross-kingdom RNAi and EV-mediated mRNA transport for virulence. In contrast to U. maydis, T. thlaspeos has retained the RNAi machinery, so that in a comparative approach, we will determine the relative contribution of mRNA and sRNA translocation to infection. What is the core cargo of EVs? Do mRNAs and sRNA target the same plant processes? In the frame of the RU5116, exRNA communication, T. thlaspeos will present the smut fungal pathogens, since it is able to use both sRNAs and mRNAs for cross-kingdom communication. We will compare RNA effectors in particular to vascular root pathogens, mutualists and pathogens during perennial infections. Thereby, we will gain detailed insight into the functional role of RNA effectors in plant-microbe interactions. In the future, elucidation of the molecular mechanisms of EV loading will be important to understand how RNAs are targeted for translocation vs. translation in the pathogen.