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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. ; The ANR grants, BOF project GOA 01G01715 and the European Union's Horizon 2020 research and innovation program under the Marie Skłodowska-Curie grant. ; http://advances.sciencemag.org ; am2021 ; Biochemistry ; Genetics ; Microbiology and Plant Pathology

11 pages, 5 figures, 1 table, supplementary materials http://advances.sciencemag.org/cgi/content/full/6/14/eaay2587/DC1.-- Data and materials availability: The genome sequence for O. mediterraneus RCC2590 and OmV2 can be found under GenBank accession numbers WMKK00000000 and MN688676, respectively. The complete gene annotations of RCC2590 can be accessed on ORCAE (https://bioinformatics.psb.ugent.be/orcae/). MMETSP sequence data can be accessed from www.imicrobe.us/#/projects/104. The genomes and their GenBank accession numbers used in this study are as follows: B. prasinos (GCA_002220235.1), M. commoda RCC299 (GCA_000090985.2), M. pusilla CCMP1545 (GCA_000151265.1), O. tauri RCC4221 (CAID01000001.2 to CAID01000020.2, CR954200.2, and CR954199.2), O. lucimarinus CCE9901 (GCA_000092065.1), BpV1 (HM004432.1), BpV2 (HM004430.1), MpV1 (HM004429.1), OtV1 (FN386611.1), OtV2 (FN600414.1), OtV5 (EU304328.2), OtV6 (JN225873.1), OlV1 (HM004431.1), OlV2 (KP874736.1), OlV3 (HQ633060.1), OlV4 (JF974316.1), OlV5 (HQ632827.1), OlV6 (HQ633059.1), OlV7 (KP874737.1), and OmV1 (KP874735.1). Ostreococcus sp. RCC809 is available from the JGI Genome Portal under project ID 16233 ; 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. ; This research was funded by the ANR grants REVIREC ANR-12-BSV7-0006-01, DECOVIR ANR-12-BSV7-0009, and PHYTNESS ANR-13-JSV6-0005. E.V. is funded by BOF project GOA 01G01715, and L.F.B. is funded by the European Union's Horizon 2020 research and innovation program under the Marie Skłodowska-Curie grant agreement no. H2020-MSCA-ITN-2015-675752

© 2008 Nature Publishing Group. This article is distributed under the terms of the Creative Commons Attribution-Noncommercial-Share Alike license. The definitive version was published in Nature Biotechnology 26 (2008): 909-915, doi:10.1038/nbt.1482. ; Plant-parasitic nematodes are major agricultural pests worldwide and novel approaches to control them are sorely needed. We report the draft genome sequence of the root-knot nematode Meloidogyne incognita, a biotrophic parasite of many crops, including tomato, cotton and coffee. Most of the assembled sequence of this asexually reproducing nematode, totaling 86 Mb, exists in pairs of homologous but divergent segments. This suggests that ancient allelic regions in M. incognita are evolving toward effective haploidy, permitting new mechanisms of adaptation. The number and diversity of plant cell wall–degrading enzymes in M. incognita is unprecedented in any animal for which a genome sequence is available, and may derive from multiple horizontal gene transfers from bacterial sources. Our results provide insights into the adaptations required by metazoans to successfully parasitize immunocompetent plants, and open the way for discovering new antiparasitic strategies. ; SCRI laboratory (V.C.B. and J.T.J.) received funding from the Scottish Government. This work benefited from links funded via COST Action 872. G.V.M. and V.L. are supported by ARC, CNRS, EMBO, MENRT and Region Rhone-Alpes. G.V.M., M.R.-R. and V.L. are also funded by the EU Cascade Network of Excellence and the integrated project Crescendo. M.-C.C. is supported by MENRT.

Vertebrates have greatly elaborated the basic chordate body plan and evolved highly distinctive genomes that have been sculpted by two whole-genome duplications. Here we sequence the genome of the Mediterranean amphioxus (Branchiostoma lanceolatum) and characterize DNA methylation, chromatin accessibility, histone modifications and transcriptomes across multiple developmental stages and adult tissues to investigate the evolution of the regulation of the chordate genome. Comparisons with vertebrates identify an intermediate stage in the evolution of differentially methylated enhancers, and a high conservation of gene expression and its cis-regulatory logic between amphioxus and vertebrates that occurs maximally at an earlier mid-embryonic phylotypic period. We analyse regulatory evolution after whole-genome duplications, and find that—in vertebrates—over 80% of broadly expressed gene families with multiple paralogues derived from whole-genome duplications have members that restricted their ancestral expression, and underwent specialization rather than subfunctionalization. Counter-intuitively, paralogues that restricted their expression increased the complexity of their regulatory landscapes. These data pave the way for a better understanding of the regulatory principles that underlie key vertebrate innovations. ; This research was funded primarily by the European Research Council (ERC) under the European Union's Horizon 2020 and Seventh Framework Program FP7 research and innovation programs (ERC-AdG-LS8-740041 to J.L.G.-S., ERC-StG-LS2-637591 to M.I., a Marie Sklodowska-Curie Grant (658521) to I.M. and a FP7/2007-2013-ERC-268513 to P.W.H.H.), the Spanish Ministerio de Economía y Competitividad (BFU2016-74961-P to J.L.G.-S., RYC-2016-20089 to I.M., BFU2014-55076-P and BFU2017-89201-P to M.I. and BFU2014-55738-REDT to J.L.G.-S, M.I. and J.R.M.-M), the 'Centro de Excelencia Severo Ochoa 2013-2017'(SEV-2012-0208), the 'Unidad de Excelencia María de Maetzu 2017-2021'(MDM-2016-0687), the People Program (Marie Curie Actions) of the European Union's Seventh Framework Program FP7 under REA grant agreement number 607142 (DevCom) to J.L.G.-S., and the CNRS and the ANR (ANR16-CE12-0008-01) to H.E. O.B. was supported by an Australian Research Council Discovery Early Career Researcher Award (DECRA; DE140101962).

This research was funded primarily by the European Research Council (ERC) under the European Union's Horizon 2020 and Seventh Framework Program FP7 research and innovation programs (ERC-AdG-LS8-740041 to J.L.G.-S., ERC-StG-LS2-637591 to M.I., a Marie Sklodowska-Curie Grant (658521) to I.M. and a FP7/2007-2013-ERC-268513 to P.W.H.H.), the Spanish Ministerio de Economía y Competitividad (BFU2016-74961-P to J.L.G.-S., RYC-2016-20089 to I.M., BFU2014-55076-P and BFU2017-89201-P to M.I. and BFU2014-55738-REDT to J.L.G.-S, M.I. and J.R.M.-M), the 'Centro de Excelencia Severo Ochoa 2013-2017'(SEV-2012-0208), the 'Unidad de Excelencia María de Maetzu 2017-2021'(MDM-2016-0687), the People Program (Marie Curie Actions) of the European Union's Seventh Framework Program FP7 under REA grant agreement number 607142 (DevCom) to J.L.G.-S., and the CNRS and the ANR (ANR16-CE12-0008-01) to H.E. O.B. was supported by an Australian Research Council Discovery Early Career Researcher Award (DECRA; DE140101962). We acknowledge the support of the CERCA Programme/Generalitat de Catalunya and of the Spanish Ministry of Economy, Industry and Competitiveness (MEIC) to the EMBL partnership. Additional sources of funding for all authors are listed in Supplementary Information. ; Vertebrates have greatly elaborated the basic chordate body plan and evolved highly distinctive genomes that have been sculpted by two whole-genome duplications. Here we sequence the genome of the Mediterranean amphioxus (Branchiostoma lanceolatum) and characterize DNA methylation, chromatin accessibility, histone modifications and transcriptomes across multiple developmental stages and adult tissues to investigate the evolution of the regulation of the chordate genome. Comparisons with vertebrates identify an intermediate stage in the evolution of differentially methylated enhancers, and a high conservation of gene expression and its cis-regulatory logic between amphioxus and vertebrates that occurs maximally at an earlier mid-embryonic phylotypic period. We analyse regulatory evolution after whole-genome duplications, and find that—in vertebrates—over 80% of broadly expressed gene families with multiple paralogues derived from whole-genome duplications have members that restricted their ancestral expression, and underwent specialization rather than subfunctionalization. Counter-intuitively, paralogues that restricted their expression increased the complexity of their regulatory landscapes. These data pave the way for a better understanding of the regulatory principles that underlie key vertebrate innovations. ; Publisher PDF ; Peer reviewed

29 pages, 9 figures, supporting information https://doi.org/10.1029/2018GB006022 ; Predicting responses of plankton to variations in essential nutrients is hampered by limited in situ measurements, a poor understanding of community composition, and the lack of reference gene catalogs for key taxa. Iron is a key driver of plankton dynamics and, therefore, of global biogeochemical cycles and climate. To assess the impact of iron availability on plankton communities, we explored the comprehensive bio‐oceanographic and bio‐omics data sets from Tara Oceans in the context of the iron products from two state‐of‐the‐art global scale biogeochemical models. We obtained novel information about adaptation and acclimation toward iron in a range of phytoplankton, including picocyanobacteria and diatoms, and identified whole subcommunities covarying with iron. Many of the observed global patterns were recapitulated in the Marquesas archipelago, where frequent plankton blooms are believed to be caused by natural iron fertilization, although they are not captured in large‐scale biogeochemical models. This work provides a proof of concept that integrative analyses, spanning from genes to ecosystems and viruses to zooplankton, can disentangle the complexity of plankton communities and can lead to more accurate formulations of resource bioavailability in biogeochemical models, thus improving our understanding of plankton resilience in a changing environment ; We thank the commitment of the following people and sponsors who made this singular expedition possible: CNRS (in particular Groupement de Recherche GDR3280, the Mission Pour l'Interdisciplinarité – Project MEGALODOM, and the Fédération de Recherche GO‐SEE FR2022), European Molecular Biology Laboratory (EMBL), Genoscope/CEA, the French Government "Investissements d'Avenir" programs Oceanomics (ANR‐11‐BTBR‐0008), MEMO LIFE (ANR‐10‐LABX‐54), PSL* Research University (ANR‐11‐IDEX‐0001‐02), and FRANCE GENOMIQUE (ANR‐10‐INBS‐09), Fund for Scientific Research – Flanders, VIB, Stazione Zoologica Anton Dohrn, UNIMIB, ANR (projects "PHYTBACK/ANR‐2010‐1709‐01," POSEIDON/ANR‐09‐BLAN‐0348, PROMETHEUS/ANR‐09‐PCS‐GENM‐217, TARA‐GIRUS/ANR‐09‐PCS‐GENM‐218, SAMOSA/ANR‐13‐ADAP‐0010, CINNAMON/ANR‐17‐CE02‐0014‐01), EU FP7 (MicroB3/No. 287589), ERC Advanced Grant Award (Diatomite: 294823), the LouisD foundation of the Institut de France, a Radcliffe Institute Fellowship from Harvard University to C. B., JSPS/MEXT KAKENHI (26430184, 16H06437, and 16KT0020), The Canon Foundation (203143100025), Gordon and Betty Moore Foundation (award #3790) and the US National Science Foundation (awards OCE#1536989 and OCE#1829831) to MBS, agnès b., the Veolia Environment Foundation, Region Bretagne, World Courier, Illumina, Cap L'Orient, the EDF Foundation EDF Diversiterre, FRB, the Prince Albert II de Monaco Foundation, Etienne Bourgois, the Fonds Français pour l'Environnement Mondial, the TARA schooner and its captain and crew. ; Peer Reviewed

Domestication of horses fundamentally transformed long-range mobility and warfare. However, modern domesticated breeds do not descend from the earliest domestic horse lineage associated with archaeological evidence of bridling, milking and corralling at Botai, Central Asia around 3500 bc3. Other longstanding candidate regions for horse domestication, such as Iberia and Anatolia, have also recently been challenged. Thus, the genetic, geographic and temporal origins of modern domestic horses have remained unknown. Here we pinpoint the Western Eurasian steppes, especially the lower Volga-Don region, as the homeland of modern domestic horses. Furthermore, we map the population changes accompanying domestication from 273 ancient horse genomes. This reveals that modern domestic horses ultimately replaced almost all other local populations as they expanded rapidly across Eurasia from about 2000 bc, synchronously with equestrian material culture, including Sintashta spoke-wheeled chariots. We find that equestrianism involved strong selection for critical locomotor and behavioural adaptations at the GSDMC and ZFPM1 genes. Our results reject the commonly held association between horseback riding and the massive expansion of Yamnaya steppe pastoralists into Europe around 3000 bc driving the spread of Indo-European languages. This contrasts with the scenario in Asia where Indo-Iranian languages, chariots and horses spread together, following the early second millennium bc Sintashta culture. ; The work by G. Boeskorov is done on state assignment of DPMGI SB RAS. This project was supported by the University Paul Sabatier IDEX Chaire d'Excellence (OURASI); Villum Funden miGENEPI research programme; the CNRS 'Programme de Recherche Conjoint' (PRC); the CNRS International Research Project (IRP AMADEUS); the France Génomique Appel à Grand Projet (ANR-10-INBS-09-08, BUCEPHALE project); IB10131 and IB18060, both funded by Junta de Extremadura (Spain) and European Regional Development Fund; Czech Academy of Sciences (RVO:67985912); the Zoological Institute ZIN RAS (АААА-А19-119032590102-7); and King Saud University Researchers Supporting Project (NSRSP–2020/2). The research was carried out with the financial support of the Russian Foundation for Basic Research (19-59-15001 and 20-04-00213), the Russian Science Foundation (16-18-10265, 20-78-10151, and 21-18-00457), the Government of the Russian Federation (FENU-2020-0021), the Estonian Research Council (PRG29), the Estonian Ministry of Education and Research (PRG1209), the Hungarian Scientific Research Fund (Project NF 104792), the Hungarian Academy of Sciences (Momentum Mobility Research Project of the Institute of Archaeology, Research Centre for the Humanities); and the Polish National Science Centre (2013/11/B/HS3/03822). This project has received funding from the European Union's Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie (grant agreement 797449). This project has received funding from the European Research Council (ERC) under the European Union's Horizon 2020 research and innovation programme (grant agreements 681605, 716732 and 834616). ; Peer reviewed