Molecular and ecophysiological diversity of phytoplankton-fungi associations.

浮游植物的真菌寄生虫无处不在，构成了水生生态系统的一个组成部分。尽管越来越多的证据表明，这些寄生真菌通过自上而下控制浮游植物水华和提供替代的碳和营养流对生态系统功能产生深远的影响，但它们在很大程度上仍未得到充分研究。这主要是由于方法上的偏见，例如，它们很难通过形态学来识别，因此经常被监视。最近，环境DNA调查显示，在水生生态系统中的非描述真菌的多样性出乎意料的大。这些未知序列的相当大一部分属于浮游植物寄生真菌。到目前为止，它们仍然在很大程度上看不见的分子生态学家，因为只有一小部分有效描述的浮游植物相关真菌被列入分子数据库。因此，本项目的主要目标是弥合形态学和分子研究之间的差距，使用经典的培养依赖和最先进的培养独立的方法。这将使环境基因组学能够获得超过世纪的丰富分类学知识，并改善水生生态系统中真菌多样性和功能之间的联系。系统发育的整合，这迄今被忽视的浮游植物上的寄生真菌组将构成一个重大贡献，解决进化的关键事件的基础上的真菌树。第二个目标是增加我们对浮游植物与真菌相互作用的生态生理特征的了解。此外，我们独特的一套模型系统使生理实验能够评估温度和光照对表现出分类学和生态学（专家与通才）变异性的特征良好的植物生长素-真菌分离株相互作用的影响。这些机制的研究将提供迄今为止失踪，但重要的基线数据，分类特异性和性状相关的生理反应的phytobacteriston-fungi的相互作用。这些数据对于改善当前和未来在全球变化背景下真菌感染对浮游植物动态以及食物网动态的预测至关重要。

Fungal parasites of phytoplankton are ubiquitous and constitute an integral component of aquatic ecosystems. Despite the growing evidence that these parasitic fungi have profound effects on ecosystem functioning via top-down control of phytoplankton blooms and by providing alternative carbon and nutrient flows, yet, they remain largely understudied. This is mainly because of methodological biases, e.g., they are difficult to identify by morphology and consequently are frequently overseen. Recently, environmental DNA surveys reveal an unexpectedly large diversity of non-described fungi in aquatic ecosystems. A substantial part of these unknown sequences belong to phytoplankton parasitic fungi. Up to date they remain largely invisible for molecular ecologists since only a tiny proportion of validly described phytoplankton associated fungi is included in the molecular databases. Therefore, the main objective of the present project is to bridge this gap between morphological and molecular studies using both classical cultivation dependent and state of the art cultivation independent approaches. This will allow environmental genomics to obtain access to more than a century wealth of taxonomic knowledge and improve the linkage between diversity and function of fungi in aquatic ecosystems. Phylogenetic integration of this hitherto neglected group of parasitic fungi on phytoplankton will constitute a major contribution to resolving evolutionary key events at the base of the fungal tree. The second objective is to increase our knowledge on the ecophysiological features of phytoplankton-fungi interactions. Additionally, our unique set of model systems enables physiological experiments to assess the effect of temperature and light on the interaction of well characterized phytoplankton-fungal isolates displaying taxonomic and ecological (specialist vs. generalist) variability. These mechanistic studies will provide hitherto missing, but important baseline data regarding taxon-specific and trait related physiological responses of phytoplankton-fungi interactions. Such data is crucial to improve current and future predictions of fungal infections on phytoplankton dynamics as well as food web dynamics in the context of global change.