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Güngör E, Savary J, Adema K, Dijkhuizen LW, Keilwagen J, Himmelbach A, Mascher M, Koppers N, Bräutigam A, Van Hove C, Riant O, Nierzwicki-Bauer S, Schluepmann H. The crane fly glycosylated triketide δ-lactone cornicinine elicits akinete differentiation of the cyanobiont in aquatic Azolla fern symbioses. PLANT, CELL & ENVIRONMENT 2024; 47:2675-2692. [PMID: 38600764 DOI: 10.1111/pce.14907] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/14/2023] [Revised: 03/02/2024] [Accepted: 03/22/2024] [Indexed: 04/12/2024]
Abstract
The restriction of plant-symbiont dinitrogen fixation by an insect semiochemical had not been previously described. Here we report on a glycosylated triketide δ-lactone from Nephrotoma cornicina crane flies, cornicinine, that causes chlorosis in the floating-fern symbioses from the genus Azolla. Only the glycosylated trans-A form of chemically synthesized cornicinine was active: 500 nM cornicinine in the growth medium turned all cyanobacterial filaments from Nostoc azollae inside the host leaf-cavities into akinetes typically secreting CTB-bacteriocins. Cornicinine further inhibited akinete germination in Azolla sporelings, precluding re-establishment of the symbiosis during sexual reproduction. It did not impact development of the plant Arabidopsis thaliana or several free-living cyanobacteria from the genera Anabaena or Nostoc but affected the fern host without cyanobiont. Fern-host mRNA sequencing from isolated leaf cavities confirmed high NH4-assimilation and proanthocyanidin biosynthesis in this trichome-rich tissue. After cornicinine treatment, it revealed activation of Cullin-RING ubiquitin-ligase-pathways, known to mediate metabolite signaling and plant elicitation consistent with the chlorosis phenotype, and increased JA-oxidase, sulfate transport and exosome formation. The work begins to uncover molecular mechanisms of cyanobiont differentiation in a seed-free plant symbiosis important for wetland ecology or circular crop-production today, that once caused massive CO2 draw-down during the Eocene geological past.
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Affiliation(s)
- Erbil Güngör
- Department of Biology, Utrecht University, Utrecht, The Netherlands
| | - Jérôme Savary
- Institute of Condensed Matter and Nanosciences, Université Catholique de Louvain, Louvain-la-Neuve, Belgium
| | - Kelvin Adema
- Department of Biology, Utrecht University, Utrecht, The Netherlands
| | | | | | - Axel Himmelbach
- Leibniz-Institute of Plant Genetics and Crop Plant Research (IPK), Seeland, Germany
| | - Martin Mascher
- Leibniz-Institute of Plant Genetics and Crop Plant Research (IPK), Seeland, Germany
| | - Nils Koppers
- Computational Biology, Center for Biotechnology and Faculty of Biology, Bielefeld University, Bielefeld, Germany
| | - Andrea Bräutigam
- Computational Biology, Center for Biotechnology and Faculty of Biology, Bielefeld University, Bielefeld, Germany
| | - Charles Van Hove
- Emeritus Professor from the Université Catholique de Louvain, Louvain-la-Neuve, Belgium
| | - Olivier Riant
- Institute of Condensed Matter and Nanosciences, Université Catholique de Louvain, Louvain-la-Neuve, Belgium
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Jenkins BH. Mutualism on the edge: Understanding the Paramecium-Chlorella symbiosis. PLoS Biol 2024; 22:e3002563. [PMID: 38573881 PMCID: PMC10994274 DOI: 10.1371/journal.pbio.3002563] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/06/2024] Open
Abstract
Exploring the mechanisms that underpin symbiosis requires an understanding of how these complex interactions are maintained in diverse model systems. The ciliate protist, Paramecium bursaria, offers a valuable insight into how emergent endosymbiotic interactions have evolved.
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Affiliation(s)
- Benjamin H. Jenkins
- Department of Biochemistry, University of Cambridge, Cambridge, United Kingdom
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3
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González-Pech RA, Li VY, Garcia V, Boville E, Mammone M, Kitano H, Ritchie KB, Medina M. The Evolution, Assembly, and Dynamics of Marine Holobionts. ANNUAL REVIEW OF MARINE SCIENCE 2024; 16:443-466. [PMID: 37552896 DOI: 10.1146/annurev-marine-022123-104345] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/10/2023]
Abstract
The holobiont concept (i.e., multiple living beings in close symbiosis with one another and functioning as a unit) is revolutionizing our understanding of biology, especially in marine systems. The earliest marine holobiont was likely a syntrophic partnership of at least two prokaryotic members. Since then, symbiosis has enabled marine organisms to conquer all ocean habitats through the formation of holobionts with a wide spectrum of complexities. However, most scientific inquiries have focused on isolated organisms and their adaptations to specific environments. In this review, we attempt to illustrate why a holobiont perspective-specifically, the study of how numerous organisms form a discrete ecological unit through symbiosis-will be a more impactful strategy to advance our understanding of the ecology and evolution of marine life. We argue that this approach is instrumental in addressing the threats to marine biodiversity posed by the current global environmental crisis.
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Affiliation(s)
- Raúl A González-Pech
- Department of Biology, The Pennsylvania State University, University Park, Pennsylvania, USA; , , , , ,
| | - Vivian Y Li
- Department of Biology, The Pennsylvania State University, University Park, Pennsylvania, USA; , , , , ,
| | - Vanessa Garcia
- Department of Biology, The Pennsylvania State University, University Park, Pennsylvania, USA; , , , , ,
| | - Elizabeth Boville
- Department of Biology, The Pennsylvania State University, University Park, Pennsylvania, USA; , , , , ,
| | - Marta Mammone
- Department of Biology, The Pennsylvania State University, University Park, Pennsylvania, USA; , , , , ,
| | | | - Kim B Ritchie
- Department of Natural Sciences, University of South Carolina, Beaufort, South Carolina, USA;
| | - Mónica Medina
- Department of Biology, The Pennsylvania State University, University Park, Pennsylvania, USA; , , , , ,
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Howe CJ, Nisbet RER. Evolution: The great photosynthesis heist. Curr Biol 2023; 33:R185-R187. [PMID: 36917940 DOI: 10.1016/j.cub.2023.01.030] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/14/2023]
Abstract
Many eukaryotes acquired chloroplasts by endosymbiotic acquisition of photosynthetic bacteria or already-domesticated chloroplasts from other eukaryotes. However, the ciliate Mesodinium rubrum acquires the nucleus of a photosynthetic eukaryote, as well as its chloroplast, resulting in dramatic metabolic remodelling in the ciliate.
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Affiliation(s)
| | - R Ellen R Nisbet
- School of Biosciences, University of Nottingham, Nottingham, UK.
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5
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Horas EL, Metzger SM, Platzer B, Kelly JB, Becks L. Context-dependent costs and benefits of endosymbiotic interactions in a ciliate-algae system. Environ Microbiol 2022; 24:5924-5935. [PMID: 35799468 DOI: 10.1111/1462-2920.16112] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2022] [Accepted: 06/20/2022] [Indexed: 01/12/2023]
Abstract
Endosymbiosis, an interaction between two species where one lives within the other, has evolved multiple times independently, but the underlying mechanisms remain unclear. Evolutionary theory suggests that for an endosymbiotic interaction to remain stable over time, births of both partners should be higher than their deaths in symbiosis and deaths of both partners should be higher than their births when living independently. However, experimentally measuring this can be difficult and conclusions tend to focus on the host. Using a ciliate-algal system (Paramecium bursaria host and Chlorella endosymbionts), we estimated the benefits and costs of endosymbiosis for both organisms using fitness measurements in different biotic environments to test under which environmental conditions the net effects of the interaction were positive for both partners. We found that the net effects of harbouring endosymbionts were positive for the ciliate hosts as it allowed them to survive in conditions of low-quality bacteria food. The algae benefitted by being endosymbiotic when predators such as the hosts were present, but the net effects were dependent on the total density of hosts, decreasing as hosts densities increased. Overall, we show that including context-dependency of endosymbiosis is essential in understanding how these interactions have evolved.
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Affiliation(s)
- Elena L Horas
- Limnology-Aquatic Ecology and Evolution, Limnological Institute, University of Konstanz, Konstanz, Germany
| | - Sarah M Metzger
- Limnology-Aquatic Ecology and Evolution, Limnological Institute, University of Konstanz, Konstanz, Germany.,Faculty of Biology, University of Freiburg, Freiburg, Germany
| | - Barbara Platzer
- Limnology-Aquatic Ecology and Evolution, Limnological Institute, University of Konstanz, Konstanz, Germany
| | - Joseph B Kelly
- Limnology-Aquatic Ecology and Evolution, Limnological Institute, University of Konstanz, Konstanz, Germany
| | - Lutz Becks
- Limnology-Aquatic Ecology and Evolution, Limnological Institute, University of Konstanz, Konstanz, Germany
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6
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Torri A, Jaeger J, Pradeu T, Saleh MC. The origin of RNA interference: Adaptive or neutral evolution? PLoS Biol 2022; 20:e3001715. [PMID: 35767561 PMCID: PMC9275709 DOI: 10.1371/journal.pbio.3001715] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Revised: 07/12/2022] [Indexed: 11/30/2022] Open
Abstract
The origin of RNA interference (RNAi) is usually explained by a defense-based hypothesis, in which RNAi evolved as a defense against transposable elements (TEs) and RNA viruses and was already present in the last eukaryotic common ancestor (LECA). However, since RNA antisense regulation and double-stranded RNAs (dsRNAs) are ancient and widespread phenomena, the origin of defensive RNAi should have occurred in parallel with its regulative functions to avoid imbalances in gene regulation. Thus, we propose a neutral evolutionary hypothesis for the origin of RNAi in which qualitative system drift from a prokaryotic antisense RNA gene regulation mechanism leads to the formation of RNAi through constructive neutral evolution (CNE). We argue that RNAi was already present in the ancestor of LECA before the need for a new defense system arose and that its presence helped to shape eukaryotic genomic architecture and stability. Where does RNA interference come from? This Essay describes a new step-by-step evolutionary model of how RNA interference might have originated in early eukaryotes through neutral events from the molecular machinery present in prokaryotes.
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Affiliation(s)
- Alessandro Torri
- Virus & RNA interference Unit, Department of Virology, Institut Pasteur, CNRS UMR 3569, Université Paris Cité, Paris, France
- * E-mail: (AT); (M-CS)
| | | | - Thomas Pradeu
- ImmunoConcEpT, CNRS UMR 5164, University of Bordeaux, Bordeaux, France
- Institut d’histoire et de philosophie des sciences et des techniques, CNRS UMR 8590, Pantheon-Sorbonne University, Paris, France
| | - Maria-Carla Saleh
- Virus & RNA interference Unit, Department of Virology, Institut Pasteur, CNRS UMR 3569, Université Paris Cité, Paris, France
- * E-mail: (AT); (M-CS)
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Geraghty S, Koutsouveli V, Hall C, Chang L, Sacristan-Soriano O, Hill M, Riesgo A, Hill A. Establishment of Host-Algal Endosymbioses: Genetic Response to Symbiont Versus Prey in a Sponge Host. Genome Biol Evol 2021; 13:6427630. [PMID: 34791195 PMCID: PMC8633732 DOI: 10.1093/gbe/evab252] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/08/2021] [Indexed: 12/13/2022] Open
Abstract
The freshwater sponge Ephydatia muelleri and its Chlorella-like algal partner is an emerging model for studying animal: algal endosymbiosis. The sponge host is a tractable laboratory organism, and the symbiotic algae are easily cultured. We took advantage of these traits to interrogate questions about mechanisms that govern the establishment of durable intracellular partnerships between hosts and symbionts in facultative symbioses. We modified a classical experimental approach to discern the phagocytotic mechanisms that might be co-opted to permit persistent infections, and identified genes differentially expressed in sponges early in the establishment of endosymbiosis. We exposed algal-free E. muelleri to live native algal symbionts and potential food items (bacteria and native heat-killed algae), and performed RNA-Seq to compare patterns of gene expression among treatments. We found a relatively small but interesting suite of genes that are differentially expressed in the host exposed to live algal symbionts, and a larger number of genes triggered by host exposure to heat-killed algae. The upregulated genes in sponges exposed to live algal symbionts were mostly involved in endocytosis, ion transport, metabolic processes, vesicle-mediated transport, and oxidation–reduction. One of the host genes, an ATP-Binding Cassette transporter that is downregulated in response to live algal symbionts, was further evaluated for its possible role in the establishment of the symbiosis. We discuss the gene expression profiles associated with host responses to living algal cells in the context of conditions necessary for long-term residency within host cells by phototrophic symbionts as well as the genetic responses to sponge phagocytosis and immune-driven pathways.
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Affiliation(s)
- Sara Geraghty
- Department of Biology, University of Richmond, Virginia, USA.,Lewis-Sigler Institute for Integrative Genomics, Princeton University, New Jersey, USA
| | - Vasiliki Koutsouveli
- Department of Life Sciences, Natural History Museum, London, United Kingdom.,Department of Marine Ecology, GEOMAR Helmholtz Centre for Ocean Research Kiel, Kiel, Germany
| | - Chelsea Hall
- Department of Biology, University of Richmond, Virginia, USA.,Department of Microbiology, Immunology, and Cancer Biology, University of Virginia, Charlottesville, Virginia, USA
| | - Lillian Chang
- Department of Biology, Bates College, Lewiston, Maine, USA
| | - Oriol Sacristan-Soriano
- Department of Biology, University of Richmond, Virginia, USA.,Centro de Estudios Avanzados de Blanes (CEAB, CSIC), Blanes, Spain
| | - Malcolm Hill
- Department of Biology, University of Richmond, Virginia, USA.,Department of Biology, Bates College, Lewiston, Maine, USA
| | - Ana Riesgo
- Department of Life Sciences, Natural History Museum, London, United Kingdom.,Department of Biodiversity and Evolutionary Biology, National Museum of Natural Sciences, Madrid, Spain
| | - April Hill
- Department of Biology, University of Richmond, Virginia, USA.,Department of Biology, Bates College, Lewiston, Maine, USA
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Emergent RNA-RNA interactions can promote stability in a facultative phototrophic endosymbiosis. Proc Natl Acad Sci U S A 2021; 118:2108874118. [PMID: 34521754 PMCID: PMC8463893 DOI: 10.1073/pnas.2108874118] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/15/2021] [Indexed: 12/11/2022] Open
Abstract
Stable endosymbiosis between eukaryotic microbes has driven the evolution of further cellular complexity. Yet the mechanisms that can act to stabilize an emergent eukaryote–eukaryote endosymbiosis are unclear. Using the model facultative endosymbiotic system, Paramecium bursaria, we demonstrate that endosymbiont–host RNA–RNA interactions can drive a cost to host growth upon endosymbiont digestion. These RNA–RNA interactions are facilitated by the host RNA-interference system. For endosymbiont messenger RNA sharing a high level of sequence identity with host transcripts, this process can result in host gene knockdown. We propose that these endosymbiont–host RNA–RNA interactions—“RNA-interference collisions”—represent an emergent mechanism to sanction the host for breakdown of the endosymbiosis, promoting the stability of the facultative endosymbiotic interaction. Eukaryote–eukaryote endosymbiosis was responsible for the spread of chloroplast (plastid) organelles. Stability is required for the metabolic and genetic integration that drives the establishment of new organelles, yet the mechanisms that act to stabilize emergent endosymbioses—between two fundamentally selfish biological organisms—are unclear. Theory suggests that enforcement mechanisms, which punish misbehavior, may act to stabilize such interactions by resolving conflict. However, how such mechanisms can emerge in a facultative endosymbiosis has yet to be explored. Here, we propose that endosymbiont–host RNA–RNA interactions, arising from digestion of the endosymbiont population, can result in a cost to host growth for breakdown of the endosymbiosis. Using the model facultative endosymbiosis between Paramecium bursaria and Chlorella spp., we demonstrate that this mechanism is dependent on the host RNA-interference (RNAi) system. We reveal through small RNA (sRNA) sequencing that endosymbiont-derived messenger RNA (mRNA) released upon endosymbiont digestion can be processed by the host RNAi system into 23-nt sRNA. We predict multiple regions of shared sequence identity between endosymbiont and host mRNA, and demonstrate through delivery of synthetic endosymbiont sRNA that exposure to these regions can knock down expression of complementary host genes, resulting in a cost to host growth. This process of host gene knockdown in response to endosymbiont-derived RNA processing by host RNAi factors, which we term “RNAi collisions,” represents a mechanism that can promote stability in a facultative eukaryote–eukaryote endosymbiosis. Specifically, by imposing a cost for breakdown of the endosymbiosis, endosymbiont–host RNA–RNA interactions may drive maintenance of the symbiosis across fluctuating ecological conditions.
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