A molecular census of land-use intensity effects on the soil biota in grasslands

土壤拥有地球上最复杂的社区，是为人类提供基本生态系统服务和粮食安全的重要资源。由于土壤的复杂性，没有关于任何土壤的包括细菌、古生物、原生动物、真菌、后生动物和病毒在内的有机体多样性的全面普查，因此很难评估土地利用强度变化对地下生物群的影响。事实上，在高分类分辨率下，没有单一的方法来评估土壤微生物区系和土壤动物多样性、丰度和群落组成。双RNA转录组学现在使得基于rRNA和mRNA的跨系统发生域和营养水平的全面普查研究成为可能。我们建议对生物多样性探索实验室草原土壤中土地利用强度对地下土壤生物群的影响进行综合的分子普查。BECENSE的主要目标是评估土地利用强度效应对整个草原土壤生物群多样性的影响。将产生150个草地样地的深度测序后的转录本，并通过微生物组的核糖体RNA和信使RNA进行分析。这种整体方法可以提供对Lui效应的独特见解，因为潜在地捕捉到了由群体之间的生物相互作用(即微生物食物网状结构)产生的新特性。我们将在两个工作包(WP)中测试四个互补的假设。WP1将测试Lui的差异在多大程度上导致草原土壤生物群的分类组成发生变化，更具体地说，是微生物食物网的结构变化。更具体地说，我们假设，与原核生物、原生生物和病毒相比，高LUI将通过土壤压实导致中型动物的丰度和多样性较低。大型动物自上而下控制的减少将通过增加原生生物、细菌和病毒微捕食者的重要性而对土壤微生物食物网产生级联效应，从而导致高LUI下土壤生态系统的营养降级。此外，在WP2中，我们的目标是揭示土壤表层和底层土壤微生物食物网中的季节和空间动态。为了掌握这项雄心勃勃的任务，来自土壤转译学、细菌和古生物微生物学以及土壤原生动物学家的专家联手提供了必要的广泛的方法学和科学背景。Be_Cense的结果将是对土地利用强度(LUI)对草原地下生物群功能协会多样性影响的前所未有的看法。

Soils host the most complex communities on Earth and are vital resources that provide essential ecosystem services and food security to humankind. Due to the complexity of soils, there is no comprehensive census about the organismic diversity comprising bacteria, archaea, protists, fungi, metazoan and viruses, for any soil, and thus the effects of land-use intensity changes on the belowground biota have been difficult to assess. In fact, there was no single method to assess soil microbiota and soil fauna diversity, abundance and community composition at high taxonomic resolution. Double-RNA metatranscriptomics now enables such holistic census studies across phylogenetic domains and trophic levels based on rRNA and mRNA. We propose an integrated molecular census of land-use intensity effects on below-ground soil biota guilds in the grassland soils of the Biodiversity Exploratories. The main objective of BE_CENSE is to assess the impact of land use intensity effects on the diversity of the whole grassland soil biota. Deeply sequenced metatranscriptomes of the 150 grassland plots will be generated and analysed via ribosomal RNA and messenger RNA of the microbiomes. Such a holistic approach can provide unique insights into LUI effects, since emergent properties resulting from biotic interactions between groups (i.e. microbial food web structures), are being potentially captured. We will test four complementary hypotheses in two work packages (WP). WP1 will test to what extend differences in LUI result in changes in the taxonomic composition of the grassland soil biota, and more specifically the structure of the microbial food web. More specifically, we hypothesize that high LUI will, via soil compaction, lead to a lower abundance and diversity of mesofauna, as compared to prokaryotes, protists and viruses. The reduced top-down control of the larger animals will have cascading effects onto the soil microbial food web by increasing the importance of protists, bacterial and viral micro-predators, thus resulting in a trophic down-grading of the soil ecosystem under high LUI. Furthermore, in WP2 we aim to reveal the seasonal and spatial dynamics in the soil microbial food web in top- and subsoils. To master this ambitious task, experts from soil metatranscriptomics, bacterial and archaeal microbiology and soil protistologists have teamed up to provide the necessary broad methodological and scientific background. The outcome of BE_CENSE will be an unprecedented view into the effects of land-use intensity (LUI) on the diversity of functional guilds in the below-ground biota in grasslands.