Funktionale Partitionierung der prokaryotischen Diversität unter verschiedenen Landnutzungsregimes
Zusammenfassung der Projektergebnisse
Plants host a “rhizobiome” – microbial communities living in, on and close to their roots, which are significantly different from those communities living in the surrounding soils. The rhizobiome benefits from the plant, e.g. by thriving on substrates delivered by the plant via a process called exudation, but it also provides essential services to plant health and therefore to the entire ecosystem. Yet, most of the processes and mechanisms underlying this interaction between plant host and the rhizobiome are not or poorly understood. We explored the structure and function of rhizobiomes of living common grassland plants in situ and their coupling to exudation patterns, plant host type and surrounding soils. In one major experiment, the rhizobiomes of six different common grassland phytometer plants were monitored, which were grown in the laboratory and then exposed to the environment. We found that the recruitment process from bulk soil communities was the major direct driver of the composition of active rhizosphere bacterial communities. Unexpectedly, the effect of soil properties, particularly soil texture, water content, and soil type, strongly dominated over plant properties and the composition of polar root exudates of the primary metabolism. We however found numerous putative taxonomic units (OTUs) or sequence variants (ASVs) linked to the presence of specific polar root exudates. Based on these experiments, we proceeded to investigate if specific populations in the rhizobiome respond to specific substrate pulses, by incubating active rhizobiomes with exudate compounds, either alone or as a mixture, under two different fertilization regimes. We both found specific taxa being differently responsive to specific substrates as well as examples for a more general response. Investigation of the genetic equipment of the involved bacteria provided further evidence for the degradation of the employed substrates. Taken together, these two experiments show that while the recruitment and maintenance of a rhizobiome is regulated strongly by soil properties, root exudation is capable to exert some control over rhizosphere recruitment. These results are important, as it was unclear whether or not different plant host types select specific rhizobiomes from the surrounding soils, as it was previously suggested from various laboratory-controlled studies. However, rhizobiomes do exist in the context of the surrounding soil compartments, and it is therefore useful to experimentally consider those bulk soils and their relationship to its vegetation cover as well. In another experiment, we could show that the type of soil aggregates – a major habitat for soil microbes – were strongly influencing the communities colonizing them, overriding the effect of simultaneously amended plant derived carbon sources. Finally, we took the opportunity to analyse the microbial communities of the near-surface horizons of 150 grasslands (and 150 woodlands) employed by the Biodiversity Exploratories at three different timepoints (2011, 2014, 2017). The size of this dataset enabled testing potential impacts of climatic variables on alpha- and beta-diversity in soils of high edaphic variability and under different management regimes. While pH was the single most important driver of alpha and beta diversity, we could also find small effects of climatic parameters on alpha diversity, with species richness declining gradually from 2011 to 2017, while the overall differences between the communities remained stable. How this loss of diversity will affect the recruitment of rhizospheres is unknown. In summary, ProFunD successfully demonstrated the functional coupling of soil microbial communities to a number of important influences by plants, soil type, edaphic and seasonal/climatic parameters.
Projektbezogene Publikationen (Auswahl)
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Evaluation of Strategies to Separate Root-Associated Microbial Communities: A Crucial Choice in Rhizobiome Research. Frontiers in Microbiology, 7(c(2016, 5, 24)).
Richter-Heitmann, Tim; Eickhorst, Thilo; Knauth, Stefan; Friedrich, Michael W. & Schmidt, Hannes
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Luteitalea pratensis gen. nov., sp. nov. a new member of subdivision 6 Acidobacteria isolated from temperate grassland soil. International Journal of Systematic and Evolutionary Microbiology, 67(5), 1408-1414.
Vieira, Selma; Luckner, Manja; Wanner, Gerhard & Overmann, Jörg
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Soil pH and plant diversity drive co-occurrence patterns of ammonia and nitrite oxidizer in soils from forest ecosystems. Biology and Fertility of Soils, 53(6), 691-700.
Stempfhuber, Barbara; Richter-Heitmann, Tim; Bienek, Lisa; Schöning, Ingo; Schrumpf, Marion; Friedrich, Michael; Schulz, Stefanie & Schloter, Michael
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Bacterial colonization of minerals in grassland soils is selective and highly dynamic. Environmental Microbiology, 22(3), 917-933.
Vieira, Selma; Sikorski, Johannes; Gebala, Aurelia; Boeddinghaus, Runa S.; Marhan, Sven; Rennert, Thilo; Kandeler, Ellen & Overmann, Jörg
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Drivers of the composition of active rhizosphere bacterial communities in temperate grasslands. The ISME Journal, 14(2), 463-475.
Vieira, Selma; Sikorski, Johannes; Dietz, Sophie; Herz, Katharina; Schrumpf, Marion; Bruelheide, Helge; Scheel, Dierk; Friedrich, Michael W & Overmann, Jörg
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Functional Traits and Spatio-Temporal Structure of a Major Group of Soil Protists (Rhizaria: Cercozoa) in a Temperate Grassland. Frontiers in Microbiology, 10(c(2019, 6, 11)).
Fiore-Donno, Anna Maria; Richter-Heitmann, Tim; Degrune, Florine; Dumack, Kenneth; Regan, Kathleen M.; Marhan, Sven; Boeddinghaus, Runa S.; Rillig, Matthias C.; Friedrich, Michael W.; Kandeler, Ellen & Bonkowski, Michael
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Contrasting Responses of Protistan Plant Parasites and Phagotrophs to Ecosystems, Land Management and Soil Properties. Frontiers in Microbiology, 11(c(2020, 8, 5)).
Fiore-Donno, Anna Maria; Richter-Heitmann, Tim & Bonkowski, Michael
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Stochastic Dispersal Rather Than Deterministic Selection Explains the Spatio-Temporal Distribution of Soil Bacteria in a Temperate Grassland. Frontiers in Microbiology, 11(c(2020, 6, 30)).
Richter-Heitmann, Tim; Hofner, Benjamin; Krah, Franz-Sebastian; Sikorski, Johannes; Wüst, Pia K.; Bunk, Boyke; Huang, Sixing; Regan, Kathleen M.; Berner, Doreen; Boeddinghaus, Runa S.; Marhan, Sven; Prati, Daniel; Kandeler, Ellen; Overmann, Jörg & Friedrich, Michael W.
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Terricaulis silvestris gen. nov., sp. nov., a novel prosthecate, budding member of the family Caulobacteraceae isolated from forest soil. International Journal of Systematic and Evolutionary Microbiology, 70(9), 4966-4977.
Vieira, Selma; Pascual, Javier; Boedeker, Christian; Geppert, Alicia; Riedel, Thomas; Rohde, Manfred & Overmann, Jörg
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Usitatibacter rugosus gen. nov., sp. nov. and Usitatibacter palustris sp. nov., novel members of Usitatibacteraceae fam. nov. within the order Nitrosomonadales isolated from soil. International Journal of Systematic and Evolutionary Microbiology, 71(2).
Vieira, Selma; Huber, Katharina J.; Neumann-Schaal, Meina; Geppert, Alicia; Luckner, Manja; Wanner, Gerhard & Overmann, Jörg
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Capillimicrobium parvum gen. nov., sp. nov., a novel representative of Capillimicrobiaceae fam. nov. within the order Solirubrobacterales, isolated from a grassland soil. International Journal of Systematic and Evolutionary Microbiology, 72(8).
Vieira, Selma; Huber, Katharina J.; Geppert, Alicia; Wolf, Jacqueline; Neumann-Schaal, Meina; Luckner, Manja; Wanner, Gerhard; Müsken, Mathias & Overmann, Jörg
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The Evolution of Ecological Diversity in Acidobacteria. Frontiers in Microbiology, 13(c(2022, 2, 2)).
Sikorski, Johannes; Baumgartner, Vanessa; Birkhofer, Klaus; Boeddinghaus, Runa S.; Bunk, Boyke; Fischer, Markus; Fösel, Bärbel U.; Friedrich, Michael W.; Göker, Markus; Hölzel, Norbert; Huang, Sixing; Huber, Katharina J.; Kandeler, Ellen; Klaus, Valentin H.; Kleinebecker, Till; Marhan, Sven; von Mering, Christian; Oelmann, Yvonne; Prati, Daniel; ... & Overmann, Jörg
