Anpassung der grünen Makroalge Ulva und ihres Mikrobioms an die niedrigen Temperaturen in der Antarktis (COLDULVA)
Zusammenfassung der Projektergebnisse
Marine macroalgae are found worldwide and can inhabit a range of diverse ecosystems. The marine green seaweed Ulva (Chlorophyta, Ulvaceae) and its associated bacteria are characterized by excellent adaptability to environmental changes. Ulva is often found in waters heavily polluted by humans and under extreme natural conditions, such as in Antarctica. Therefore, the holobiont Ulva must have successfully overcome many stressors to become the established population we know today. The extensive network of interactions between species is an essential aspect of life on earth and is also very typical for Ulva. Any disruption to these cross-kingdom interactions can significantly impact the dynamics and biodiversity of ecological communities, especially when they promote the growth and development of these species. Comprehensive knowledge of these interactions is thus crucial to classifying various pressures, such as accelerated climate change, on the balance of those parts of the ecosystem that depend on species interactions. The project COLDULVA (i.e., cold Ulva) was designed to study the cold adaptability of Ulva by the direct comparison of warm- (Mediterranean) and cold-adapted (Antarctic) species. Ulva was introduced as an emerging model organism providing unique features, such as a sequenced genome, controlled laboratory culture (axenic) and life cycle control, for new research lines in algal ecophysiological and developmental biology. Symbiotic epiphytic bacteria synergistically affect green seaweeds significantly and the host fitness involving ecophysiology, metabolism, growth, development, reproduction, environmental adaptation and evolution. As a result of our research, a unique reductionistic model system of Ulva and two essential bacteria for algal morphogenesis has been established. COLDULVA demonstrated that essential algal growth and morphogenesispromoting bacteria could be found independently of their origin and habitat in Antarctica. However, the holobiont of warm and cold-adapted Ulva react differentially to cold stress. Cold stress triggered diverse potential cryoprotectants in warm- and cold-adapted Ulva. Metabolomic approaches revealed that taurine, proline and DMSP might be considered species-specific algal stress biomarkers. Interestingly ectoine is only produced and released by the associated stressed bacteria. Of particular importance was COLDULVA's observation that the morphogenic thallusin is only provided appropriately by cold-adapted bacteria (newly isolated in Antarctica as part of the project) and ensures the development of Ulva at 2°C. Ulva only reacts thus adequately to cold stress as its microbiome can provide the necessary algal growth-promoting factors (e.g., thallusin). Main achievements of COLDULVA in summary: (1) Ulva spp., water and bacteria spp. were collected from King George Island (Antarctica) during the research stay at Carlini station (Dallmann Laboratory) in 2020. (2) Upon microbiome analysis of about 90 samples, an exhaustive screening of morphogenetic activities employing the bacteria collected from the Antarctic (~600 species) was performed to determine whether they produce algal growth- and morphogenesis-promoting factors (AGMPF) such as thallusin. (3) Comparison of the endo-metabolome of U. mutabilis (Mediterranean) and Ulva sp. (Antarctic), which was isolated on King George Island, revealed a species-specific response through typical cryoprotective compounds, such as DMSP, taurine, proline and ectoine, at cold temperatures. (4) MALDI MS imaging was evaluated on the Ulva tripartite system (axenic gametes and associated bacteria) to determine specific compounds to detect bacteria on the algal surface. (5) A new tripartite system has been established using Ulva and bacteria isolated from Antarctica. Bacterial cross-exchange assays are now possible to investigate the bacterial role in cold algal adaptation.
Projektbezogene Publikationen (Auswahl)
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'Biodiversity and adaptation of polar algae and their interactions with symbionts and parasites in a changing environment', in T. Fromm, C. Oberdieck, T. Matz, C. Wesche (eds) Reports on polar and marine research 745, Alfred Wegener Institute for Polar and Marine Research: Bremerhaven, pp. 93-103
Wichard, T.; Ghaderiardakani, F.; Zimmermann, J.; Karsten, K.; Grossart, H.-P. & Livenets, A.
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Microbiome-Dependent Adaptation of Seaweeds Under Environmental Stresses: A Perspective. Frontiers in Marine Science, 7(c(2020, 12, 16)).
Ghaderiardakani, Fatemeh; Quartino, Maria Liliana & Wichard, Thomas
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NCBI, PRJNA828511, SRR19647641
Morales-Reyes; et al.
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"A new glance at the chemosphere of macroalgal-bacterial interactions: In situ profiling of metabolites in symbiosis by mass spectrometry", Max Planck repository Edmond
Vallet; et al.
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A new glance at the chemosphere of macroalgal–bacterial interactions: In situ profiling of metabolites in symbiosis by mass spectrometry. Beilstein Journal of Organic Chemistry, 17(c(2021, 5, 19)), 1313-1322.
Vallet, Marine; Kaftan, Filip; Grabe, Veit; Ghaderiardakani, Fatemeh; Fenizia, Simona; Svatoš, Aleš; Pohnert, Georg & Wichard, Thomas
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Antarctic Glacial Meltwater Impacts the Diversity of Fungal Parasites Associated With Benthic Diatoms in Shallow Coastal Zones. Frontiers in Microbiology, 13(c(2022, 3, 4)).
Ilicic, Doris; Woodhouse, Jason; Karsten, Ulf; Zimmermann, Jonas; Wichard, Thomas; Quartino, Maria Liliana; Campana, Gabriela Laura; Livenets, Alexandra; Van den Wyngaert, Silke & Grossart, Hans-Peter
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Effects of Reversal of Water Flow in an Arctic Floodplain River on Fluvial Emissions of CO2 and CH4. Journal of Geophysical Research: Biogeosciences, 127(1).
Castro‐Morales, K.; Canning, A.; Körtzinger, A.; Göckede, M.; Küsel, K.; Overholt, W. A.; Wichard, T.; Redlich, S.; Arzberger, S.; Kolle, O. & Zimov, N.
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Genome Sequence of Halomonas sp. Strain MS1, a Metallophore-Producing, Algal Growth-Promoting Marine Bacterium Isolated from the Green Seaweed Ulva mutabilis (Chlorophyta). Microbiology Resource Announcements, 11(11).
Morales-Reyes, Cristina F.; Ghaderiardakani, Fatemeh & Wichard, Thomas
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Metabolite profiling reveals insights into the species-dependent cold stress response of the green seaweed holobiont Ulva (Chlorophyta). Environmental and Experimental Botany, 200(c(2022, 8)), 104913.
Ghaderiardakani, Fatemeh; Langhans, Linda; Kurbel, Valentin B.; Fenizia, Simona & Wichard, Thomas
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NCBI, PRJNA828511, SRR18835785 - SRR18835790
Ghaderiardakani; et al.
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Zenodo
Castro-Morales; et al.
