Fungal development of Verticillium resting structures and plant infection

土壤传播的植物致病性大丽花黄萎病菌形成黑化的微菌核，可以在土壤中休息和存活十多年。这种休眠真菌生存结构的发育通常与特定次生代谢物的生物合成有关。微菌核的萌发是由适当寄主植物的根分泌物触发的，这导致真菌菌丝直接向植物的根生长。大丽花在根皮层定植并侵入维管系统。在木质部开始分生，利用汁液流在植物内分配真菌。真菌在宿主体内定植可导致疾病症状，如萎黄、坏死、生长迟缓或萎蔫。植物致病性大丽花弧菌感染多达400种植物，包括重要的农业作物，并在世界范围内造成越来越大的经济损失。本研究项目旨在描述黄萎病Vta-Som1-Velvet与未折叠蛋白反应Hac1转录因子之间的复杂相互作用。这些调节因子通过根进入植物木质部系统，协调了大丽花发育和感染的顺序和相互关联的遗传网络。这些网络，我们已经在第一个资助期确定，控制微核的形成，作为土壤中休息和生存的结构。它们发芽，真菌在植物上定居，最后在季节结束时再次开始形成微核。在真菌定殖过程中或在土壤中减少大丽花弧菌微核形成的控制机制的详细分子认识将非常有帮助。VTA-SOM1-VELVET网络响应外部生物（如根际微生物群、植物）和非生物环境以及内部信号通路。VTA-SOM1-VELVET网络控制和调节基因表达，使真菌在生长、防御、发育或分泌中做出适当的反应。我们将分析(i)不同的大丽花VTA-SOM1-VELVET基因网络是如何协调和连接的，以及哪些基因是由特定转录因子直接控制的。我们将（ii）确定翻译后修饰，包括磷酸化和泛素化/去泛素化，并检查VTA-SOM1-VELVET遗传网络转录因子的蛋白质稳定性控制机制及其对真菌发育和毒力的影响。我们将结合遗传学，细胞生物学，蛋白质组学，代谢组学以及致病性实验，包括例如缺失菌株的产生和调查，GFP-pulldown, ChIPSeq，根和植物感染。我们的目标是详细了解生长季节末微菌核形成所需的分子控制步骤，土壤中萌发的微菌核产生的菌丝，真菌根附着和植物寄主的定植以及疾病症状诱导。

Soil-borne plant-pathogenic Verticillium dahliae fungi form melanised microsclerotia, which can rest and survive for more than a decade in the soil. Development of such dormant fungal survival structures is often linked to the biosynthesis of specific secondary metabolites. Germination of microsclerotia is triggered by root exudates of appropriate host plants, which results in directed fungal hyphal growth towards plant roots. V. dahliae colonises the root cortex and invades the vascular system. Conidiation is started in the xylem to use the sap stream for distribution of the fungus within the plant. Fungal colonisation within the host can result in disease symptoms, such as chlorosis, necrosis, stunted growth or wilting. Plant-pathogenic V. dahliae infects up to 400 plants including agriculturally important crops and causes increasing economical damage worldwide. This research project aims to characterise the complex interplay between Verticillium Vta-Som1-Velvet and unfolded protein response Hac1 transcription factors. These regulators orchestrate sequential and interconnected genetic networks for development and infection of V. dahliae through the roots into the plant xylem system. These networks, which we have identified in the first funding period, control the formation of microsclerotia as resting and survival structures in the soil. They germinate, the fungus colonises the plant and finally microsclerotia formation is initiated again at the end of the season. A detailed molecular understanding of control mechanisms, which reduce V. dahliae microsclerotia formation during fungal colonisation of host plants or in soil would be very helpful. VTA-SOM1-VELVET networks respond to the external biotic (e.g. microbiomes in rhizosphere, plant) and abiotic environment as well as to internal signalling pathways. The VTA-SOM1-VELVET networks control and adapt gene expression for the appropriate fungal reply in growth, defense, development or secretion. We will analyse (i) how the different V. dahliae VTA-SOM1-VELVET gene networks are coordinated and connected and which genes are directly controlled by specific transcription factors. We will (ii) determine posttranslational modifications including phosphorylation and ubiquitination/deubiquitination and examine protein stability control mechanisms of transcription factors of the VTA-SOM1-VELVET genetic networks and their impact on fungal development and virulence. We will use a combination of genetic, cell biological, proteomic, metabolomic as well as pathogenicity experiments including for example the generation and investigation of deletion strains, GFP-pulldown, ChIPSeq, root and plant infection. Our goal is the detailed understanding of molecular control steps required for microsclerotia formation at the end of the growing season, for the hyphae derived from germinating microsclerotia in the soil, to fungal root attachment and colonisation of the plant host and disease symptom induction.