Functional role of phyllosphere fungi in litter decomposition in response to land use

欧洲山毛榉（Fagus sylvatica）是中欧最重要和研究最多的树木之一。和所有的树木一样，它拥有种类繁多的内生真菌。然而，内生真菌的群落结构知之甚少，主要是由于涉及的环境因素的多样性。此外，内生真菌在生态系统过程中的功能多样性和生态作用，如碳和氮循环，几乎是清楚的。然而，最近的研究表明，相当一部分的内生菌群落也存在于凋落物中，并具有降解死亡植物材料的酶促能力。 在这里，我们努力解开生态地理模式，季节动态和土地利用的依赖山毛榉内生真菌，它们在叶凋落物降解和真菌殖民的两个栖息地（生活和腐烂的叶子）的生命周期的作用。特别是，我们测试的假设，通过促进树个人增强防御能力，造林有利于建立主机或栖息地适应内生真菌，分解落叶比适应真菌更有效，从而有助于更显着的营养cycle.The设计的生物多样性exploratories解开这种复杂的连接提供了一个宝贵的先决条件。除了合作小组提供的环境背景数据外，还将持续监测叶片生理学和生物化学，为最终讨论评估的分子数据提供基础。DNA和RNA衍生标记的下一代测序（NGS）将评估内生真菌和落叶降解真菌对区域，环境和土地利用梯度的探索性设计所代表的群落结构和活动概况的季节动态。NGS还将分析落叶中的元转录组，以确定真菌群落实际表达的分解酶编码基因。的基本过程和驱动因素将详细讨论在实验室实验中，温度制度和凋落物质量对不同的山毛榉叶内生真菌的基因表达谱的影响，将在分解过程中进行评估。该项目将提供一个巨大的数据库，除了宿主植物的生理和生化特性外，还将从分子上描述探索站中山毛榉内生真菌和凋落物降解真菌群落的特征。特别是元转录组学数据有可能揭示模式，并启动远远超出所述假设的假设，特别是作为营养循环和物种相互作用建模的基础。因此，假设驱动的方法将得到数据驱动的研究的补充，我们认为这将对未来的生态系统过程研究产生重大影响，而不仅仅是在生物多样性探索。

The European Beech (Fagus sylvatica) is one of the most important and best studied trees in Central Europe. As all trees, it hosts an immense diversity of endophytic fungi. However, community structure of endophytic fungi is poorly understood, mostly due to the multiplicity of environmental factors involved. Furthermore, the functional diversity and ecological role of endophytic fungi in ecosystem processes, such as carbon and nitrogen cycling, is all but clear. Recent studies, however, showed that a considerable fraction of the endophytic community is also present in litter and has the enzymatic capabilities to degrade dead plant material. Here, we strive for unravelling biogeographical patterns, seasonal dynamics and land-use-dependency of beech-endophyllous fungi, their role in leaf-litter degradation and the life cycles of fungi colonizing the two habitats (living and decaying leaves). In particular, we test the implications of the hypothesis that by promoting tree individuals with enhanced defence capabilities, silviculture favours the establishment of host or habitat adapted endophytic fungi, which decompose leaf-litter more efficiently than less adapted fungi, thus contributing more significantly to the nutrient cycles.The design of the biodiversity exploratories provides an invaluable prerequisite for unravelling such complex connections. In addition to the available environmental background data from collaborating groups, leaf physiology and biochemistry will be consistently monitored to provide the basis for conclusively discussing the assessed molecular data. Next Generation Sequencing (NGS) of DNA- and RNA-derived markers will assess seasonal dynamics in community structure and activity profiles of endophytic and leaf-litter degrading fungi against regional, environmental and land-use gradients represented by the exploratory design. Metatranscriptomes in leaf-litter will be also analysed by NGS, to identify decomposition enzyme coding genes actually expressed by the fungal community. The underlying processes and driving factors will be addressed in detail in laboratory experiments, in which the impact of temperature regimes and litter quality on gene expression profiles of different beech-leaf-endophytic fungi, will be assessed during decomposition. The project will provide an immense data pool, molecularly characterising beech-endophyllous and litter degrading fungal communities in the exploratories, in addition to the physiological and biochemical characterisation of the host plants. In particular the metatranscriptomic data have the potential to reveal patterns and initiate hypotheses far beyond the addressed hypotheses, especially by serving as a basis for modelling nutrient cycles and species interactions. Accordingly, the hypothesis-driven approach will be complemented by data-driven research, which we assume to have a major impact on future studies on ecosystem processes, not only in the biodiversity-exploratories.