Plant–microbe interactions in deep time: A multidisciplinary study of Permian microorganisms associated with tree ferns, and their responses to climate change

晚古生代冰期（宾夕法尼亚-二叠纪）的结束导致了植被动态的显著变化和热带气候的反复变化。因此，这个时间间隔可以看作是当今全球变化的模拟。虽然许多研究都集中在这一动态时期对生态系统造成深刻变化和大规模影响的参数上，但针对当地社区特定生物相互作用的小规模调查却非常罕见。德国Manebach的下二叠纪，图林根森林盆地参考剖面的一部分，已经收集了近200年，特别是全球分布的树蕨Psaronius的标本。由于最近的几项研究对该地点的地质学、地层学、古生态学和气候学提供了新的见解，对古生态系统及其主要植物成分之一的更完整的描述现在已经成为可能，并将提供对其生命和保存的地质生物学限制的见解。基于保存非常完好的历史标本和新收集的标本，我们将研究在Psaronius和其他3d保存的植物的不同组织中发生的真菌和真菌样微生物的不同组合。我们将记录与植物相关的微生物多样性，绘制出它们的分布模式，并评估与寄主植物相互作用的各种微生物的生物学性质，以了解个体植物作为栖息地和微生态系统的相互关系水平。我们将调查的埋藏条件和途径，导致微生物在植物内的特殊保存。在2016年的挖掘之后，我们开始了对沉积环境和特定保存情况的研究，从而获得了独特的生态系统快照。我们认为，我们的研究结果将大大增加对早二叠纪植物和微生物之间相互关系以及它们如何响应气候和环境变化的认识。我们将有助于更好地了解不同微生物在其生活的生态系统中所起的作用，以及它们如何影响陆地群落的进化。研究将集中在一个动态的古环境，它嵌套在一个区域间可追溯的湿相在西苏拉纪，代表了最后的煤沼泽避难所之一，在Variscan内部。我们的综合方法包括地质现场工作，基于薄片的光显微解剖研究，阴极发光和扫描电子显微镜与背散射电子和电子背散射衍射的定向对比成像，以及气相色谱-质谱地球化学研究，以评估埋藏过程和限制。

The end of the late Paleozoic ice age (Pennsylvanian-Permian) resulted in considerable changes of vegetation dynamics and repeated variations in tropical climate. This time interval can therefore be viewed as an analogue of present-day global change. While many studies have focused on the parameters causing profound changes and large-scale effects on the ecosystems that occurred during this dynamic period of time, small-scale investigations that address specific organismal interactions in local communities are very rare. The lower Permian of Manebach, Germany, part of the Thuringian Forest Basin reference section, have been collected for nearly 200 years, in particular for specimens of the globally distributed tree fern Psaronius. As several recent studies have provided new insights into geology, stratigraphy, palaeoecology and -climatology of that site, a more complete characterization of the palaeoecosystem and one of its major plant constituents has now become possible and will provide insights into the geo-biological constraints of its life and preservation. Based on exceptionally well preserved historical specimens and newly collected ones, we will investigate the diverse assemblages of fungi and fungus-like microorganisms that occur within the different tissues of Psaronius and other 3D-preserved plants. We will document the diversity of microbes associated with the plants, map out their distribution patterns, and assess the biological nature of the various microbial interactions with the host plants in order to understand the levels of interrelatedness that characterized individual plants as habitats and micro-ecosystems. We will investigate the taphonomic conditions and pathways that have led to the exceptional preservation of microorganisms within the plants. Following the 2016 excavation, we have initiated research on the sedimentary environment and specific preservation circumstances that have resulted in unique snapshots of the ecosystem. We submit that the outcomes from our research will substantially increase the knowledge of the interrelationships between plants and microbes and how they responded to climate and environmental change in the early Permian. We will contribute to a better understanding of the roles different microorganisms played in the ecosystems in which they lived, and how they affected the evolution of terrestrial communities. Study will focus on a dynamic palaeoenvironment that was nested within an interregional traceable wet phase in the Cisuralian and represents one of the last coal swamp refugia in the Variscan interior. Our integrative approach encompasses methods, e.g., geological field work, light-microscopic anatomical study based on thin sections, cathodoluminescence and scanning electron microscopy with orientation contrast imaging by backscattered electrons and electron backscatter diffraction, and gas chromatography–mass spectrometry geochemical studies to assess taphonomic processes and constraints.