Molecular and physiological mechanisms of fungal parasitism and their ecological consequences in polar waters

底栖硅藻作为极地水生生态系统的初级生产者发挥着重要的生态作用，因为它们为包括鱼类在内的较高营养级提供食物。然而，很少有人知道它们的生物量生产如何受到寄生虫的影响，例如被称为壶菌的基础真菌。在以前的一个项目中，我们发现了在南极和北极地区频繁发生和高度多样性的壶菌。然而，我们无法机械地研究它们在食物网动态和碳循环中的生态作用，特别是在全球气候变化情景下。因此，根据SPP 1158南极研究，我们的项目解决了两个主要的首要问题：通往下奥陶德群岛的门户和二。应对环境变化。将与其他SPP成员在Potter Cove（Dallmann Lab，Carlini Station，Antarctica）和Kongsfjorden（AWIPEW Station，Ny-Svalbard）进行实地工作。我们的主要问题是：在不同的环境条件下，宿主-寄生虫（底栖藻类-壶菌）的动力学和生理学如何变化，环境变化如何影响壶菌寄生虫的生态作用，以及它们如何在温暖的海洋中完全黑暗的时期生存？将处理四个目标：i）通过实地和实验研究（包括在南极的Potter Cove和北极的Kongsfjorden），评价和比较不同环境条件下的宿主-寄生虫动态。微观和分子工具）。ii）在两个研究地点，使用实地和实验研究（包括：代谢组学）。㈢确定在不断变化的环境条件下宿主-寄生虫相互作用的生态作用，并比较南极和北极的研究地点。iv）定义寄生虫策略，以在变暖的海洋中持续黑暗的时期生存，并通过代谢组学结合实验室和现场孵育在细胞水平上描述宿主-寄生虫系统。我们将测试以下假设：H1：主机寄生虫（底栖藻类壶菌）的“多样性”的变化，作为对不断变化的环境（即温度和光照）的响应。H2：预测的环境变化将影响宿主-寄生虫的“相互作用”，并对它们在极地沿海沃茨的生态作用产生影响，这可能导致南极与北极地点的海底食物网和碳循环的差异。H3：在完全黑暗和低温（1°C;极地冬季）期间，寄生虫形成特殊的休息阶段和/或切换到通才策略。我们的研究将提供一个mechananimous洞察气候变化相关的影响，底栖生物的生态作用，壶菌相互作用及其后果的食物网动态，因此C-循环。单细胞代谢组学和元转录组学的结合，使人们能够探索在极地地区基本上被忽视的底栖原生生物-寄生虫相互作用的代谢后果。

Benthic diatoms play an ecologically important role as primary producers for polar aquatic ecosystems as they provide food for higher trophic levels including fish. Yet, little is known how their biomass production is affected by parasites, e.g. basal fungi called chytrids. In a previous project, we detected the frequent occurrence and a high diversity of chytrids in both Antarctica and the Arctic. Yet, we were not able to mechanistically study their ecological role for food web dynamics and C-cycling, in particular under global climate change scenarios. Thus, in accordance with SPP 1158 Antarctic Research, our project addresses the two major overarching questions: I. Gateways to Lower Latitudes and II. Response to Environmental Change. Field work will be performed with other SPP members at Potter Cove (Dallmann Lab, Carlini Station, Antarctica) and Kongsfjorden (AWIPEW Station, Ny-Ålesund, Svalbard). Our main questions are: How do host-parasite (benthic alga-chytrids) dynamics and physiology change under different environmental conditions, how will environmental change affect the ecological role of chytrid parasites, and how do they survive periods of complete darkness in a warming ocean? Four goals will be addressed: i) Evaluate and compare host-parasite dynamics under different environmental conditions in Potter Cove (Antarctica) vs. Kongsfjorden (Arctic) via field and experimental studies (incl. microscopic and molecular tools). ii) At both study sites, examine and compare changes in host-parasite physiology under changing environmental conditions using field and experimental studies (incl. metabolomics). iii) Determine the ecological role of host-parasite interactions under changing environmental conditions and compare both Antarctic vs. Arctic study sites. iv) Define parasite strategies to survive periods of continuous darkness in a warming ocean and describe the host-parasite system on the cellular level via metabolomics combined with lab and field incubations. We will test the following hypotheses: H1: Host-parasite (benthic alga-chytrid) “diversity” changes as a response to a changing environment (i.e. temperature and light availability). H2: Predicted environmental changes will affect host-parasite “interactions” with implications for their ecological role in polar coastal waters, which may lead to differences in benthic food webs and C-cycling at Antarctic vs. Arctic sites. H3: During periods of complete darkness and low temperatures (1°C; polar winter), parasites form special resting stages and/or switch to generalist strategies. Our study will provide a mechanistical insight into climate-change related impacts on the ecological role of benthic diatom-chytrid interactions and their consequences for food web dynamics and hence C-cycling. The combination of single cell metabolomics and metatranscriptomics enables to explore metabolic consequences of largely neglected benthic protist-parasites interactions in polar regions.