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2. NICOTIANAMINE SYNTHASE activity affects nucleolar iron accumulation and impacts rDNA silencing and RNA methylation in Arabidopsis

Author

Montacié, Charlotte, primary, Riondet, Christophe, additional, Wei, Lili, additional, Darrière, Tommy, additional, Weiss, Alizée, additional, Pontvianne, Frédéric, additional, Escande, Marie-Line, additional, de Bures, Anne, additional, Jobet, Edouard, additional, Barbarossa, Adrien, additional, Carpentier, Marie-Christine, additional, Aarts, Mark G M, additional, Attina, Aurore, additional, Hirtz, Christophe, additional, David, Alexandre, additional, Marchand, Virginie, additional, Motorin, Yuri, additional, Curie, Catherine, additional, Mari, Stéphane, additional, Reichheld, Jean-Philippe, additional, and Sáez-Vásquez, Julio, additional

Published
2023
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3. NICOTIANAMINE SYNTHASE activity affects nucleolar iron accumulation and impacts rDNA silencing and RNA methylation in Arabidopsis

Author

Montacié, Charlotte, Riondet, Christophe, Wei, Lili, Darrière, Tommy, Weiss, Alizée, Pontvianne, Frédéric, Escande, Marie Line, De Bures, Anne, Jobet, Edouard, Barbarossa, Adrien, Carpentier, Marie Christine, Aarts, Mark G.M., Attina, Aurore, Hirtz, Christophe, David, Alexandre, Marchand, Virginie, Motorin, Yuri, Curie, Catherine, Mari, Stéphane, Reichheld, Jean Philippe, Sáez-Vásquez, Julio, Montacié, Charlotte, Riondet, Christophe, Wei, Lili, Darrière, Tommy, Weiss, Alizée, Pontvianne, Frédéric, Escande, Marie Line, De Bures, Anne, Jobet, Edouard, Barbarossa, Adrien, Carpentier, Marie Christine, Aarts, Mark G.M., Attina, Aurore, Hirtz, Christophe, David, Alexandre, Marchand, Virginie, Motorin, Yuri, Curie, Catherine, Mari, Stéphane, Reichheld, Jean Philippe, and Sáez-Vásquez, Julio

Abstract

In plant cells, a large pool of iron (Fe) is contained in the nucleolus, as well as in chloroplasts and mitochondria. A central determinant for intracellular distribution of Fe is nicotianamine (NA) generated by NICOTIANAMINE SYNTHASE (NAS). Here, we used Arabidopsis thaliana plants with disrupted NAS genes to study the accumulation of nucleolar iron and understand its role in nucleolar functions and more specifically in rRNA gene expression. We found that nas124 triple mutant plants, which contained lower quantities of the iron ligand NA, also contained less iron in the nucleolus. This was concurrent with the expression of normally silenced rRNA genes from nucleolar organizer regions 2 (NOR2). Notably, in nas234 triple mutant plants, which also contained lower quantities of NA, nucleolar iron and rDNA expression were not affected. In contrast, in both nas124 and nas234, specific RNA modifications were differentially regulated in a genotype dependent manner. Taken together, our results highlight the impact of specific NAS activities in RNA gene expression. We discuss the interplay between NA and nucleolar iron with rDNA functional organization and RNA methylation.

Published
2023

6. Features of the Opportunistic Behaviour of the Marine Bacterium Marinobacter algicola in the Microalga Ostreococcus tauri Phycosphere

Author

Pinto, Jordan, primary, Lami, Raphaël, additional, Krasovec, Marc, additional, Grimaud, Régis, additional, Urios, Laurent, additional, Lupette, Josselin, additional, Escande, Marie-Line, additional, Sanchez, Frédéric, additional, Intertaglia, Laurent, additional, Grimsley, Nigel, additional, Piganeau, Gwenaël, additional, and Sanchez-Brosseau, Sophie, additional

Published
2021
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8. Virus-host coexistence in phytoplankton through the genomic lens

Author

Yau, Sheree, Krasovec, Marc, Benites, L. Felipe, Rombauts, Stephane, Groussin, Mathieu, Vancaester, Emmelien, Aury, Jean-marc, Derelle, Evelyne, Desdevises, Yves, Escande, Marie-line, Grimsley, Nigel, Guy, Julie, Moreau, Hervé, Sanchez-brosseau, Sophie, Van De Peer, Yves, Vandepoele, Klaas, Gourbiere, Sebastien, Piganeau, Gwenael, Yau, Sheree, Krasovec, Marc, Benites, L. Felipe, Rombauts, Stephane, Groussin, Mathieu, Vancaester, Emmelien, Aury, Jean-marc, Derelle, Evelyne, Desdevises, Yves, Escande, Marie-line, Grimsley, Nigel, Guy, Julie, Moreau, Hervé, Sanchez-brosseau, Sophie, Van De Peer, Yves, Vandepoele, Klaas, Gourbiere, Sebastien, and Piganeau, Gwenael

Abstract

Virus-microbe interactions in the ocean are commonly described by “boom and bust” dynamics, whereby a numerically dominant microorganism is lysed and replaced by a virus-resistant one. Here, we isolated a microalga strain and its infective dsDNA virus whose dynamics are characterized instead by parallel growth of both the microalga and the virus. Experimental evolution of clonal lines revealed that this viral production originates from the lysis of a minority of virus-susceptible cells, which are regenerated from resistant cells. Whole-genome sequencing demonstrated that this resistant-susceptible switch involved a large deletion on one chromosome. Mathematical modeling explained how the switch maintains stable microalga-virus population dynamics consistent with their observed growth pattern. Comparative genomics confirmed an ancient origin of this “accordion” chromosome despite a lack of sequence conservation. Together, our results show how dynamic genomic rearrangements may account for a previously overlooked coexistence mechanism in microalgae-virus interactions.

Published
2020
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9. Responses to iron oxide and zinc oxide nanoparticles in echinoderm embryos and microalgae: uptake, growth, morphology, and transcriptomic analysis

Author

Genevière, Anne-marie, Derelle, Evelyne, Escande, Marie-line, Grimsley, Nigel, Klopp, Christophe, Ménager, Christine, Michel, Aude, Moreau, Hervé, Genevière, Anne-marie, Derelle, Evelyne, Escande, Marie-line, Grimsley, Nigel, Klopp, Christophe, Ménager, Christine, Michel, Aude, and Moreau, Hervé

Abstract

We investigated the toxicity of Iron oxide and Zinc oxide engineered nanoparticles (ENPs) on Paracentrotus lividus sea urchin embryos and three species of microalgae. Morphological responses, internalization, and potential impacts of Fe2O3 and ZnO ENPs on physiology and metabolism were assessed. Both types of ENPs affected P. lividus larval development, but ZnO ENPs had a much stronger effect. While growth of the alga Micromonas commoda was severely impaired by both ENPs, Ostreococcus tauri or Nannochloris sp. were unaffected. Transmission electron microscopy showed the internalization of ENPs in sea urchin embryonic cells while only nanoparticle interaction with external membranes was evidenced in microalgae, suggesting that marine organisms react in diverse ways to ENPs. Transcriptome-wide analysis in P. lividus and M. commoda showed that many different physiological pathways were affected, some of which were common to both species, giving insights about the mechanisms underpinning toxic responses

Published
2020
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10. Virus-host coexistence in phytoplankton through the genomic lens

Author

Agence Nationale de la Recherche (France), European Commission, Agencia Estatal de Investigación (España), Yau, Sheree, Rombauts, Stéphane, Benites, L. Felipe, Groussin, Mathieu, Vancaester, Emmelien, Aury, Jean‐Marc, Derelle, Evelyne, Desdevises, Yves, Escande, Marie-Line, Grimsley, Nigel, Guy, Julie, Moreau, Hervé, Sanchez-Brosseau, Sophie, Van de Peer, Yves, Vandepoele, Klaas, Gourbiere, Sebastien, Piganeau, Gwenael, Agence Nationale de la Recherche (France), European Commission, Agencia Estatal de Investigación (España), Yau, Sheree, Rombauts, Stéphane, Benites, L. Felipe, Groussin, Mathieu, Vancaester, Emmelien, Aury, Jean‐Marc, Derelle, Evelyne, Desdevises, Yves, Escande, Marie-Line, Grimsley, Nigel, Guy, Julie, Moreau, Hervé, Sanchez-Brosseau, Sophie, Van de Peer, Yves, Vandepoele, Klaas, Gourbiere, Sebastien, and Piganeau, Gwenael

Abstract

Virus-microbe interactions in the ocean are commonly described by “boom and bust”dynamics, whereby a numerically dominant microorganism is lysed and replaced by a virus-resistant one. Here, we isolated a microalga strain and its infective dsDNA virus whose dynamics are characterized instead by parallel growth of both the microalga and the virus. Experimental evolution of clonal lines revealed that this viral production originates from the lysis of a minority of virus-susceptible cells, which are regenerated from resistant cells. Whole-genome sequencing demonstrated that this resistant-susceptible switch involved a large deletion on one chromosome. Mathematical modeling explained how the switch maintains stable microalga-virus population dynamics consistent with their observed growth pattern. Comparative genomics confirmed an ancient origin of this “accordion” chromosome despite a lack of sequence conservation. Together, our results show how dynamic genomic rearrangements may account for a previously overlooked coexistence mechanism in microalgae-virus interactions.

Published
2020

13. Virus-host coexistence in phytoplankton through the genomic lens

Author

Yau, Sheree, primary, Krasovec, Marc, additional, Benites, L. Felipe, additional, Rombauts, Stephane, additional, Groussin, Mathieu, additional, Vancaester, Emmelien, additional, Aury, Jean-Marc, additional, Derelle, Evelyne, additional, Desdevises, Yves, additional, Escande, Marie-Line, additional, Grimsley, Nigel, additional, Guy, Julie, additional, Moreau, Hervé, additional, Sanchez-Brosseau, Sophie, additional, Van de Peer, Yves, additional, Vandepoele, Klaas, additional, Gourbiere, Sebastien, additional, and Piganeau, Gwenael, additional

Published
2020
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15. Virus-host coexistence in phytoplankton through the genomic lens: Supplementary Material

Author

Yau, Sheree, Krasovec, Marc, Rombauts, Stephane, Groussin, Mathieu, Benites, Luiz Felipe, Vancaester, Emmelien, Aury, Jean-Marc, Derelle, Evelyne, Desdevises, Yves, Escande, Marie-Line, Grimsley, Nigel, Guy, Julie, Moreau, Herve, Sanchez-Brosseau, Sophie, van de Peer, Yves, Vandepoele, Klaas, Gourbiere, Sebastien, and Piganeau, Gwenael

Subjects
viruses
Abstract

Phytoplankton-virus interactions are major determinants of geochemical cycles in the oceans. Viruses are responsible for the redirection of carbon and nutrients away from larger organisms back towards microorganisms via the lysis of microalgae in a process coined the "viral shunt". Virus-host interactions are generally expected to follow "boom and bust" dynamics, whereby a numerically dominant strain is lysed and replaced by a virus resistant strain. Here, we isolated a microalga and its infective nucleo-cytoplasmic large DNA virus (NCLDV) concomitantly from the environment in the surface NW Mediterranean Sea, Ostreococcus mediterraneus, and show continuous growth in culture of both the microalga and the virus. Evolution experiments through single cell bottlenecks demonstrate that, in the absence of the virus, susceptible cells evolve from one ancestral resistant single cell, and vice-versa; that is that resistant cells evolve from one ancestral susceptible cell. This provides evidence that the observed sustained viral production is the consequence of a minority of virus-susceptible cells. The emergence of these cells is explained by low-level phase switching between virus-resistant and virus-susceptible phenotypes, akin to a bet hedging strategy. Whole genome sequencing and analysis of the ~14 Mb microalga and the ~200 kb virus points towards ancient speciation of the microalga within the Ostreococcus species complex and frequent gene exchanges between prasinoviruses infecting Ostreococcus species. Re-sequencing of one susceptible strain demonstrated that the phase switch involved a large 60 Kb deletion of one chromosome. This chromosome is an outlier chromosome compared to the streamlined, gene dense, GC-rich standard chromosomes, as it contains many repeats and few orthologous genes. While this chromosome has been described in three different genera, its size increments have been previously associated to antiviral immunity and resistance in another species from the same genus. Mathematical modelling of this mechanism predicts microalga-virus population dynamics consistent with the observation of continuous growth of both virus and microalga. Altogether, our results suggest a previously overlooked strategy in phytoplankton-virus interactions.

Published
2019
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16. Developmental and comparative transcriptomic identification of iridophore contribution to white barring in clownfish

Author

Salis, Pauline, primary, Lorin, Thibault, additional, Lewis, Victor, additional, Rey, Carine, additional, Marcionetti, Anna, additional, Escande, Marie‐Line, additional, Roux, Natacha, additional, Besseau, Laurence, additional, Salamin, Nicolas, additional, Sémon, Marie, additional, Parichy, David, additional, Volff, Jean‐Nicolas, additional, and Laudet, Vincent, additional

Published
2019
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17. Virus-host coexistence in phytoplankton through the genomic lens

Author

Sheree, Yau, primary, Krasovec, Marc, additional, Rombauts, Stephane, additional, Groussin, Mathieu, additional, Benites, L. Felipe, additional, Vancaester, Emmelien, additional, Aury, Jean-Marc, additional, Derelle, Evelyne, additional, Desdevises, Yves, additional, Escande, Marie-Line, additional, Grimsley, Nigel, additional, Guy, Julie, additional, Moreau, Hervé, additional, Sanchez-Brosseau, Sophie, additional, van de Peer, Yves, additional, Vandepoele, Klaas, additional, Gourbiere, Sebastien, additional, and Piganeau, Gwenael, additional

Published
2019
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19. Mantoniella beaufortii and Mantoniella baffinensis sp. nov. (Mamiellales, Mamiellophyceae), two new green algal species from the high arctic1.

Author

Yau, Sheree, Lopes dos Santos, Adriana, Eikrem, Wenche, Gérikas Ribeiro, Catherine, Gourvil, Priscillia, Balzano, Sergio, Escande, Marie‐Line, Moreau, Hervé, and Vaulot, Daniel

Subjects
SEA ice, SPECIES, SPECIES distribution
Abstract

Members of the class Mamiellophyceae comprise species that can dominate picophytoplankton diversity in polar waters. Yet, polar species are often morphologically indistinguishable from temperate species, although clearly separated by molecular features. Here we examine four Mamiellophyceae strains from the Canadian Arctic. The 18S rRNA and Internal Transcribed Spacer 2 (ITS2) gene phylogeny place these strains within the family Mamiellaceae (Mamiellales, Mamiellophyceae) in two separate clades of the genus Mantoniella. ITS2 synapomorphies support their placement as two new species, Mantoniella beaufortii and Mantoniella baffinensis. Both species have round green cells with diameter between 3 and 5 μm, one long flagellum and a short flagellum (~1 μm) and are covered by spiderweb‐like scales, making both species similar to other Mantoniella species. Morphologically, M. beaufortii and M. baffinensis are most similar to the cosmopolitan M. squamata with only minor differences in scale structure distinguishing them. Screening of global marine metabarcoding data sets indicates M. beaufortii has only been recorded in seawater and sea ice samples from the Arctic, while no environmental barcode matches M. baffinensis. Like other Mamiellophyceae genera that have distinct polar and temperate species, the polar distribution of these new species suggests they are cold or ice‐adapted Mantoniella species. [ABSTRACT FROM AUTHOR]

Published
2020
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25. Morphology, Genome Plasticity, and Phylogeny in the Genus Ostreococcus Reveal a Cryptic Species, O. mediterraneus sp. nov. (Mamiellales, Mamiellophyceae)

Author

Subirana, Lucie, primary, Péquin, Bérangère, additional, Michely, Stéphanie, additional, Escande, Marie-Line, additional, Meilland, Julie, additional, Derelle, Evelyne, additional, Marin, Birger, additional, Piganeau, Gwenaël, additional, Desdevises, Yves, additional, Moreau, Hervé, additional, and Grimsley, Nigel H., additional

Published
2013
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32. Mantoniella beaufortii and Mantoniella baffinensis sp. nov. (Mamiellales, Mamiellophyceae), two new green algal species from the high arctic1.

Author

Yau, Sheree, Lopes dos Santos, Adriana, Eikrem, Wenche, Gérikas Ribeiro, Catherine, Gourvil, Priscillia, Balzano, Sergio, Escande, Marie‐Line, Moreau, Hervé, and Vaulot, Daniel

Subjects
*SEA ice, *SPECIES, *SPECIES distribution
Abstract

Members of the class Mamiellophyceae comprise species that can dominate picophytoplankton diversity in polar waters. Yet, polar species are often morphologically indistinguishable from temperate species, although clearly separated by molecular features. Here we examine four Mamiellophyceae strains from the Canadian Arctic. The 18S rRNA and Internal Transcribed Spacer 2 (ITS2) gene phylogeny place these strains within the family Mamiellaceae (Mamiellales, Mamiellophyceae) in two separate clades of the genus Mantoniella. ITS2 synapomorphies support their placement as two new species, Mantoniella beaufortii and Mantoniella baffinensis. Both species have round green cells with diameter between 3 and 5 μm, one long flagellum and a short flagellum (~1 μm) and are covered by spiderweb‐like scales, making both species similar to other Mantoniella species. Morphologically, M. beaufortii and M. baffinensis are most similar to the cosmopolitan M. squamata with only minor differences in scale structure distinguishing them. Screening of global marine metabarcoding data sets indicates M. beaufortii has only been recorded in seawater and sea ice samples from the Arctic, while no environmental barcode matches M. baffinensis. Like other Mamiellophyceae genera that have distinct polar and temperate species, the polar distribution of these new species suggests they are cold or ice‐adapted Mantoniella species. [ABSTRACT FROM AUTHOR]

Published
2020
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33. Mantoniella beaufortii and Mantoniella baffinensis sp. nov. (Mamiellales, Mamiellophyceae), two new green algal species from the high arctic 1 .

Author

Yau S, Lopes Dos Santos A, Eikrem W, Gérikas Ribeiro C, Gourvil P, Balzano S, Escande ML, Moreau H, and Vaulot D

Subjects
Arctic Regions, Canada, Phylogeny, Seawater, Chlorophyta
Abstract

Members of the class Mamiellophyceae comprise species that can dominate picophytoplankton diversity in polar waters. Yet, polar species are often morphologically indistinguishable from temperate species, although clearly separated by molecular features. Here we examine four Mamiellophyceae strains from the Canadian Arctic. The 18S rRNA and Internal Transcribed Spacer 2 (ITS2) gene phylogeny place these strains within the family Mamiellaceae (Mamiellales, Mamiellophyceae) in two separate clades of the genus Mantoniella. ITS2 synapomorphies support their placement as two new species, Mantoniella beaufortii and Mantoniella baffinensis. Both species have round green cells with diameter between 3 and 5 μm, one long flagellum and a short flagellum (~1 μm) and are covered by spiderweb-like scales, making both species similar to other Mantoniella species. Morphologically, M. beaufortii and M. baffinensis are most similar to the cosmopolitan M. squamata with only minor differences in scale structure distinguishing them. Screening of global marine metabarcoding data sets indicates M. beaufortii has only been recorded in seawater and sea ice samples from the Arctic, while no environmental barcode matches M. baffinensis. Like other Mamiellophyceae genera that have distinct polar and temperate species, the polar distribution of these new species suggests they are cold or ice-adapted Mantoniella species., (© 2019 Phycological Society of America.)

Published
2020
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