Soils and plant microbial communities are intricately linked to ecosystem functioning as they play important roles in nutrients dynamics as decomposers and feedback to plant communities as mutualists and pathogens. Numerous soil physicochemical factors as well as the land use management are shaping the composition and dynamics of microbial community. In addition, global warming and climate change are the most prominent of all environmental factors that influence all kinds of the living organisms including microbes associated to the plant soil systems. A better understanding of the environmental drivers shaping these microbial communities especially under future climate will help to understand and predict the expected changes of ecosystems functions and accordingly of the services they provide. In addition, such knowledge will help to detect potential ways on how soil microorganisms can be harnessed to help mitigating the negative consequences of climate change.The Global Change Experimental Facility (GCEF) is settled in the field research station of the Helmholtz Centre for Environmental Research (UFZ) in Bad Lauchstädt, Saxony-Anhalt, Germany (51_22’60 N, 11_50’60 E, 118 m a.s.l.). This facility has been designed to investigate the consequences of a predicted future climate scenario expected in 50-70 years in Central Germany on ecosystem processes under different land-use regimes applied on large field plots in comparison to similar sets of plots under the ambient climate. We performed our study using this research facility, with the aim to analyze the impact of future climate conditions, soil physicochemical factors, and/or land use type and intensity on microbial communities in different habitats (rhizosphere soil, plant endosphere, and plant residues) in grassland and cropland ecosystems. To assess the microbial communities, we used the highly sensitive and powerful highthroughput next generation sequencing, Illumina Miseq.This thesis constitutes the first assessment of microbial communities in the GCEF experimental facility. The samples were collected in 2015 for manuscript 4, while for manuscripts 1, 2, 3, 5, 6, the samples were collected in 2018-2019. Manuscript 1: (Sansupa, Wahdan, Hossen et al., 2021; Applied Science 2021, 11, 688) “Can we use functional annotation of prokaryotic taxa (FAPROTAX) to assign the ecological functions of investigated the potential use of FAPROTAX for bacterial functional annotation in non-aquatic ecosystems, specifically in soil. For this study, we used microbial datasets of soil systems including rhizosphere soil of Trifolium pratense from the extensively used meadow plots in the GCEF. We hypothesized that FAPROTAX can be used in terrestrial ecosystems. Our survey revealed that FAPROTAX tool can be used for screening or grouping of 16S derived bacterial data from terrestrial ecosystems and its performance could be enhanced through improving the taxonomic and functional reference databases. Manuscript 2: (Wahdan et al., 2021; Frontiers in Microbiology 12:629169) “Targeting the active rhizosphere microbiome of Trifolium pratense in grassland evidences a stronger-than-expected belowground biodiversity-ecosystem functioning link”. In this study, we used the bromodeoxyuridine (BrdU) immunocapture technique combined with pair-end Illumina sequencing to differentiate between total and active microbiomes (including both bacteria and fungi) in the rhizosphere of T. pratense. In the same rhizosphere soil samples, we also measured the activities of three microbial extracellular hydrolytic enzymes, (ß-glucosidase, N-acetylglucosaminidase, and acid phosphatase), which play central roles in the C, N, and P acquisition. We investigated the proportion of active and total rhizosphere microbiomes, and their responses to the manipulated future climate in the GCEF. In addition, we identified the possible links between total and active microbiomes and the soil ecosystem function (extracellular enzyme production). Our results revealed that the active microbes of the rhizosphere represented 42.8 and 32.1% of the total bacterial and fungal operational taxonomic units (OTUs), respectively. Active and total microbial fractions were taxonomically and functionally diverse and displayed different responses to variations of soil physicochemical factors. We also showed that the richness of overall and specific functional groups of active microbes in rhizosphere soil significantly correlated with the measured enzyme activities, while total microbial richness did not. Manuscript 3: (Wahdan et al., 2021; Microbiology Open 10:e1217) “Deciphering Trifolium pratense L. (red clover) holobiont reveals a resistant microbial community assembly to future climate changes predicted for the next 50–70 years”. We investigated the microbial communities of bacteria and fungi associated with four plant parts of T. pratense (the rhizosphere and the endopheres of the roots, whole shoot system (leaves and stems), and of the flower) and evaluated their potential ecological and metabolic functions in response to future climate conditions. This study was performed on the GCEF extensively managed grassland plots. Our analyses indicated that plant tissue/compartments differentiation enables the formation of a unique ecological niches that harbor specific microbial communities. Except for the fungal communities of the aboveground compartments, T. pratense microbiome diversity and community composition showed a resistance against the future climate changes. We also analyzed the predicted bacterial metabolic functional genes of red clover. Thereby, we detected microbial genes involved in plant growth processes, such as biofertilisation (nitrogen fixation, phosphorus solubilisation, and siderophore biosynthesis) and biostimulation (phytohormone and auxin production), which were not influenced by the future climate. Manuscript 4: (Wahdan et al., 2021; Environmental Microbiology) “Organic agricultural practice enhances arbuscular mycorrhizal symbiosis in correspondence to soil warming and altered precipitation patterns”. This study was performed on the conventional and organic farming plots under both ambient and future climate conditions. We evaluated the effect of climate (ambient vs. future), agricultural practice (conventional vs. organic farming) and their interaction on Arbuscular Mycorrhizal Fungi (AMF) community composition and richness inside wheat roots. In addition, we evaluated the relationship between molecular richness of indigenous root AMF and wheat yield parameters. Future climate altered the total AMF community composition and a sub-community of Glomeraceae. Further, application of different agricultural practices altered both total AMF and Glomeraceae community, whereby organic farming appeared to enhance total AMF and Diversisporaceae richness. Under the future climate scenario, organic farming enhanced total AMF and Gigasporaceae richness in comparison with conventional farming. Our results revealed a positive correlation between AMF richness and wheat nutrient contents not only in organic farming system but also under conventionally managed fields. Manuscript 5: (Wahdan et al., 2020; Microorganisms 8, 908) “Future climate significantly alters fungal plant pathogen dynamics during the early phase of wheat litter decomposition”. This study was performed on the conventional farming plots. We investigated the structure and ecological functions of fungal communities colonizing wheat during the early phase of decomposition (0, 30, and 60 days) under current and future climate conditions. We found that plant pathogenic fungi dominated (~87% of the total sequences) within the wheat residue mycobiome. Destructive wheat fungal pathogens such as Fusarium graminearum, Fusarium tricinctum, and Zymoseptoria tritci were detected under ambient and future climates. Additionally, the future climate brought new pathogens to the system. Manuscript 6: (Wahdan et al., 2021; Microbial Ecology 10.1007/s00248-021-01840-6) “Life in the wheat litter: effects of future climate on microbiome and function during the early phase of decomposition”. This study was performed on the conventional farming plots. We assessed the effects of climate change on microbial richness, community compositions, interactions and their functions (production of extracellular enzymes) in decomposing residues of wheat. In addition, we investigated the effects of climate change on litter residues physicochemical factors as well as on mass loss during the early phase of decomposition. Future climate significantly accelerated litter mass loss as compared with ambient one. Our results indicated that future climate significantly increased fungal richness and altered fungal communities over time, while bacterial communities were more resistant in wheat residues. Fungi corresponded to different physicochemical elements of litter under ambient (C, Ca2+ and pH) and future (C/N, N, P, K+, Ca2+ and pH) climate conditions. Also, a highly correlative interactions between richness of bacteria and fungi were detected under future climate. Activities of microbial β-glucosidase and N-acetylglucosaminidase in wheat straw were significantly higher under future climate. Such high enzymatic activities were coupled with a significant positive correlation between microbial (both bacteria and fungi) richness and community compositions with these two enzymatic activities only under future climate.:CONTENTS BIBLIOGRAPHIC DESCRIPTION……………………………………………….......III ZUSAMMENFASSUNG………………………………………………………...........V SUMMARY……………………………………………………………………………..X GENERAL INTRODUCTION…………………………………………………………………...............1 I-1 Ecosystem functions carried out by soil and plant microbiomes…………………..2 I-2 Biodiversity and functional diversity and maintenance of ecosystem functions……………..3 I-3 Total vs. active microbial diversity for assessing ecosystem functions……………4 I-4 Factors influencing soil and plant microbiota…………………………………..……6 I-4.1 Elements of climate changes……………………………………………................7 I-4.2 Climate changes influence microbes in an interacting, complex manner………8 I-4.3 Environmental factors controlling the response of microorganisms to climate changes………………………………………………………………………………….....10 I-5 Interplay between climate and land use intensity in agroecosystems……………11 I-6 Study site, and overall objectives………………………………………………....…12 I-7 Methods used for the taxonomic and functional characterization of the microbiomes……...15 I-8 Presentation of aims and hypotheses of the publications/manuscripts in different chapters.................................................................................................................16 I-9References.........................................................................................................20 CHAPTER 1 Can we use functional annotation of prokaryotic taxa (FAPROTAX) to assign the ecological functions of soil bacteria? .....................................................................29 Publication…………………………………………………………………………...........31 Supplementary materials…………………………………………………………….......42 CHAPTER 2 Targeting the active rhizosphere microbiome of Trifolium pratense in grassland evidences a stronger-than-expected belowground biodiversity-ecosystem functioning link………………..........................................................................…49 Publication………………………………………………………………………………51 Supplementary materials……………………………………………………………..67 CHAPTER 3 Deciphering Trifolium pratense L. holobiont reveals a microbiome resilient to future climate changes……………………………………………….…………………………..89 Publication………………………………………………………………………………….91 Supplementary materials……………………………………………………………….111 CHAPTER 4 Organic agricultural practice enhances arbuscular mycorrhizal symbiosis in correspondence to soil warming and altered precipitation patterns………………125 Publication……………………………………………………………………………….127 Supplementary materials………………………………………………………….......140 CHAPTER 5 Future climate significantly alters fungal plant pathogen dynamics during the early phase of wheat litter decomposition…...................………………….……………..156 Publication………………………………………………...…………….….…………...158 Supplementary materials………………………………………………….…....……..175 CHAPTER 6 Life in the wheat litter: effects of future climate on microbiome and function during the early phase of decomposition…………………………………….....……....…….181 Publication…………………………………..…………………………………….....…...183 Supplementary materials………………………………………………………………..199 GENERAL DISCUSSION…………………………………………………………….......210 D-I Approaches and main findings of the result chapters………………………..…211 D-2 Conclusion and implications of the study findings…………………………...…215 D-3 Technical limitation of the study……………………………………………......…217 D-4 Future prospects of the study field ...……………………………………………217 D-5 References…………………………………………………………………………..219 DATA AVAILABILITY……………………………………………………………………...223 ACKNOWLEDGEMENTS……………………………………………………………......224 CURRICULUM VITAE……………………………………………………………….....…225 LIST OF PUBLICATIONS………………………………………………………….........226 CONFERENCE PROCEEDINGS…………………………………………………….....227 STATUTORY DECLARATION………………………………………………................228 VERIFICATION OF AUTHOR PARTS……………………………………………........229

[pt] A contaminação de solos por hidrocarbonetos é uma real preocupação ambiental em muitas partes do mundo devido a crescente dependência econômica dos derivados do petróleo, principalmente os combustíveis fósseis que estão frequentemente sujeitos a vazamentos e derramamentos acidentais. Estudos capazes de entender os mecanismos de biodegradação dos componentes da gasolina no solo não saturado se fazem necessários, pois auxiliam no processo de tomada de decisões em relação ao gerenciamento e controle da propagação em subsuperfície. No Brasil, o etanol é utilizado como aditivo oxigenado à gasolina e alguns autores sugerem para solo saturado que, por ser mais degradável, ele atrasa a degradação dos outros componentes mais tóxicos desse combustível. O trabalho anterior realizado por esse grupo de pesquisa para solo não saturado obteve conclusões semelhantes às já constatadas para solo saturado. No entanto, os mecanismos de degradação na zona não saturada ainda foram pouco estudados e compreendidos. Este estudo tem como objetivo analisar a degradação do contaminante em blocos não saturados indeformados de solo arenoso e siltoso, oriundos do município de Duque de Caxias – RJ, submetidos a um pulso de contaminante. Dois blocos, um arenoso (BA) e outro argiloso (BS), foram contaminados pela solução de dois porcento de Benzeno, quatro porcento de Tolueno em Heptano (BT); outros dois blocos, também um arenoso (EA) e outro argiloso (ES), foram submetidos à mesma solução adicionados etanol a vinte porcento (BTE). Foram realizados ensaios com a finalidade de monitorar a atividade degradadora total do meio, carbono disponível, perfil metabólico da microbiota, concentração dos contaminantes, além de medições da umidade volumétrica através do uso do Time Domain Reflectometer (TDR). A atividade microbiana inicial, antes da contaminação, apresentou valores baixos. Logo após a contaminação dos blocos, àqueles sujeitos a etanol apresentaram ausência de atividade enquanto os sujeitos apenas à mistura BT mostraram um aumento, contrariando as expectativas. As atividades microbianas oscilaram ao longo de todo o experimento o que pode indicar uma adaptação da microbiota às novas condições do meio. Com base nos resultados dos ensaios e monitoramentos realizados, podemos sugerir que o principal fator determinante para alteração da atividade foi à composição do solo. O contaminante não exerceu a influência esperada e vista nos estudos anteriores. / [en] The soil contamination by hydrocarbons is a real environmental concern in many parts of the world due to growing economic dependence on petroleum, mostly fossil fuels are often subject to leaks and accidental spills. Studies able to understand the mechanisms of biodegradation of gasoline components in unsaturated soil are necessary because they help in making decisions regarding the management and control of the propagation process in the subsurface. In Brazil, ethanol is used as an oxygenate gasoline additive and some authors suggest that for saturated soils, being more degradable, it delays the degradation of other more toxic components of this fuel. The previous study by this research group to unsaturated soil obtained similar results to those already observed for saturated soil. However, the mechanism of degradation in the unsaturated zone have few studies. This study aims to analyze the degradation mechanisms of the contaminant in unsaturated blocks of sand and silt soil from the city of Duque de Caxias - RJ, subjected to a pulse of contaminant. Two blocks, one sandy (BA) and silty (BS), were contaminated by two percent solution of benzene, four percent toluene in heptane (BT); other two blocks, also sandy (EA) and silty (ES), underwent the same solution added to twenty percent ethanol (BTE). Analyzes were performed to monitor the overall activity of the degrading medium, available carbon, the microbiota metabolic profile, concentration of the contaminants were performed as well as measurements of the water content through the use of Time Domain Reflectometer (TDR). The initial microbial activity before the contamination, showed low values. Soon after contamination of the blocks, those subjected to ethanol showed no activity while subject to BT mixture showed an increase, contrary to expectations. Microbial activities ranged throughout the experiment which may indicate an adaptation of microbes to new environmental conditions. Based on the results of testing and monitoring conducted, we suggest that the main determinant for changing the activity factor was the composition of the soil. The contaminant did not exert the expected influence and seen in previous studies

Animal pollination represents one of the key innovations of the flowering plants, and constitutes an essential ecological service in most ecosystems. While pollinators are the main drivers of flower evolution, some floral traits are puzzling when viewed only in the context of this mutualistic interaction. In particular, the pollen of plants belonging to several families has spines or compounds with toxic effects on insects. Little is known about the causes and consequences of these enigmatic floral traits. Yet, pollen defences might play an important role in pollination given that pollen is the main source of food of the principal pollinators in most ecosystems: bees. My thesis investigates why plants sometimes have seemingly defended pollen and how these putative defences affect host-plant use by bees. Given the potential role of flower-colonizing microbes in pollination, I also investigate the potential for these microorganisms to influence flower evolution. I found that pollinators are unlikely to act as potential agents of selection on the concentration of defence compounds in the pollen of Lupinus argenteus. Rather, physiological spillover or pleiotropy from tissues highly defended against herbivores might be responsible for a baseline level of defence compounds in pollen, while such compounds could also mediate the interaction between plants and pollen-colonizing microbes. However, I did not find evidence that flower-colonizing microbes drive the evolution of floral traits in an experimental study. I also found that pollen chemical and mechanical defences likely restrict pollen-host use by Osmiini, a group of solitary bees exhibiting high interspecific variability in their pollen diet. Bees tolerated the defences of their pollen hosts, but were often harmed by the pollen defences of co-occuring plants exploited by other Osmiini species. This pattern provides a striking parallel with the evolution of host-use in herbivorous insects feeding on vegetative tissues, and suggests that pollen defences might play an important role in structuring plant–bee interactions. Overall, my thesis contributes to our understanding of the causes of the presence of chemical defences in pollen and their consequences for the pollination mutualism.

The contaminated book as a cultural asset is presented from three perspectives: philosophy, microbiology and cultural studies including medieval studies. The prejudice of the microbe as the enemy of the collection is questioned. Instead, the microbe is brought to the fore and made contextually visible as a book-biographical sign: traces on the book, including microbial ones, can bear witness to fire, flood, evacuation, and historical epidemics. For this witnessing, different readings of 'world' and of 'dead/living' must be considered, working toward a theory of things. It is based on studies of objects in medieval anthologies in the holdings of the Leipzig University Library, which have also been studied using microbiological and molecular biological methods at the DSMZ-German Collection of Microorganisms and Cell Cultures in Braunschweig. For the determination of the book biographies, both collections form mutual references. A new readability of the 'world as a book' is shown, which is made readable through its DNA, but also through its cultivation needs. With the idea of the book as habitat, a new view of the relationship between cultural property and microbe is opened - against destructive contamination towards the microbe as innovation potential for collections.

Metagenomics is a cultivation-independent approach for obtaining the genomic composition of microbial communities. Microbial communities are ubiquitous in nature. Microbes which are associated with the human body play important roles in human health and disease. These roles span from protecting us against infections from other bacteria, to being the causes of these diseases. A deeper understanding of these communities and how they function inside our bodies allows for advancements in treatments and preventions for these diseases. Recent developments in metagenomics have been driven by the emergence of Next-Generation Sequencing technologies and Third-Generation Sequencing technologies that have enabled cost-effective DNA sequencing and the generation of large volumes of genomic data. These technologies have allowed for the introduction of hybrid DNA assembly techniques to recover the genomes of the constituent microbes. While Next-Generation Sequencing technologies use paired-end sequencing reads from DNA fragments into short reads and have a relatively lower error rate, Third-Generation Sequencing technologies use much longer DNA fragments to generate longer reads, bringing contigs together for larger scaffolds with a higher error rate. Hybrid assemblers leverage both short and long read sequencing technologies and can be a critical step in the advancements of metagenomics, combining these technologies to allow for longer assemblies of DNA with lower error rates. We evaluate the strengths and weaknesses of the hybrid assembly framework using several state-of-the-art assemblers and simulated human microbiome datasets. Our work provides insights into metagenomic assembly and genome recovery, an important step towards a deeper understanding of the microbial communities that influence our well-being.

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