1
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Gollnisch R, Ahrén D, Rengefors K. Single-cell genomics of a bloom-forming phytoplankton species reveals population genetic structure across continents. THE ISME JOURNAL 2024; 18:wrae045. [PMID: 38489771 PMCID: PMC11065318 DOI: 10.1093/ismejo/wrae045] [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: 09/30/2023] [Revised: 12/30/2023] [Indexed: 03/17/2024]
Abstract
The study of microbial diversity over time and space is fundamental to the understanding of their ecology and evolution. The underlying processes driving these patterns are not fully resolved but can be studied using population genetic approaches. Here we investigated the population genetic structure of Gonyostomum semen, a bloom-forming phytoplankton species, across two continents. The species appears to be expanding in Europe, whereas similar trends are not observed in the USA. Our aim was to investigate if populations of Gonyostomum semen in Europe and in the USA are genetically differentiated, if there is population genetic structure within the continents, and what the potential drivers of differentiation are. To this end, we used a novel method based on single-amplified genomes combined with Restriction-site Associated DNA sequencing that allows de novo genotyping of natural single-cell isolates without the need for culturing. We amplified over 900 single-cell genomes from 25 lake populations across Europe and the USA and identified two distinct population clusters, one in Europe and another in the USA. Low genetic diversity in European populations supports the hypothesized recent expansion of Gonyostomum semen on this continent. Geographic population structure within each continent was associated with differences in environmental variables that may have led to ecological divergence of population clusters. Overall, our results show that single-amplified genomes combined with Restriction-site Associated DNA sequencing can be used to analyze microalgal population structure and differentiation based on single-cell isolates from natural, uncultured samples.
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Affiliation(s)
- Raphael Gollnisch
- Department of Biology, Aquatic Ecology, Lund University, 22362 Lund, Sweden
- Department of Earth Sciences, University of Oxford, Oxford OX1 3AN, UK
| | - Dag Ahrén
- National Bioinformatics Infrastructure Sweden (NBIS), SciLifeLab, Department of Biology, Lund University, 22362 Lund, Sweden
| | - Karin Rengefors
- Department of Biology, Aquatic Ecology, Lund University, 22362 Lund, Sweden
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2
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Pearman JK, Thomson-Laing G, Thompson L, Waters S, Vandergoes MJ, Howarth JD, Duggan IC, Hogg ID, Wood SA. Human access and deterministic processes play a major role in structuring planktonic and sedimentary bacterial and eukaryotic communities in lakes. PeerJ 2022; 10:e14378. [PMID: 36389411 PMCID: PMC9661969 DOI: 10.7717/peerj.14378] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2022] [Accepted: 10/20/2022] [Indexed: 11/13/2022] Open
Abstract
Lakes provide habitat for a diverse array of species and offer a wide range of ecosystem services for humanity. However, they are highly vulnerable as they are not only impacted by adverse actions directly affecting them, but also those on the surrounding environment. Improving knowledge on the processes responsible for community assembly in different biotic components will aid in the protection and restoration of lakes. Studies to date suggested a combination of deterministic (where biotic/abiotic factors act on fitness differences amongst taxa) and stochastic (where dispersal plays a larger factor in community assembly) processes are responsible for structuring biotic communities, but there is no consensus on the relative roles these processes play, and data is lacking for lakes. In the present study, we sampled different biotic components in 34 lakes located on the South Island of New Zealand. To obtain a holistic view of assembly processes in lakes we used metabarcoding to investigate bacteria in the sediment and surface waters, and eukaryotes in the sediment and two different size fractions of the water column. Physicochemical parameters were collected in parallel. Results showed that deterministic processes dominated the assembly of lake communities although the relative importance of variable and homogeneous selection differed among the biotic components. Variable selection was more important in the sediment (SSbact and SSeuks) and for the bacterioplankton (Pbact) while the assembly of the eukaryotic plankton (SPeuks, LPeuks) was driven more by homogeneous selection. The ease of human access to the lakes had a significant effect on lake communities. In particular, clade III of SAR11 and Daphnia pulex were only present in lakes with public access. This study provides insights into the distribution patterns of different biotic components and highlights the value in understanding the drivers of different biological communities within lakes.
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Affiliation(s)
| | | | | | | | | | | | | | - Ian D. Hogg
- University of Waikato, Hamilton, New Zealand,Canadian High Arctic Research Station, Nunavut, Canada
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3
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Grupstra CGB, Lemoine NP, Cook C, Correa AMS. Thank you for biting: dispersal of beneficial microbiota through 'antagonistic' interactions. Trends Microbiol 2022; 30:930-939. [PMID: 35393166 DOI: 10.1016/j.tim.2022.03.006] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2021] [Revised: 03/08/2022] [Accepted: 03/09/2022] [Indexed: 12/23/2022]
Abstract
Multicellular organisms harbor populations of microbial symbionts; some of these symbionts can be dispersed through the feeding activities of consumers. Studies of consumer-mediated microbiota dispersal generally focus on pathogenic microorganisms; the dispersal of beneficial microorganisms has received less attention, especially in the context of 'antagonistic' trophic interactions (e.g., herbivory, parasitism, predation). Yet, this 'trophic transmission' of beneficial symbionts has significant implications for microbiota assembly and resource species (e.g., prey) health. For example, trophic transmission of microorganisms could assist with environmental acclimatization and help resource species to suppress other consumers or competitors. Here, we highlight model systems and approaches that have revealed these potential 'silver-linings' of antagonism as well as opportunities and challenges for future research.
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Affiliation(s)
- C G B Grupstra
- BioSciences Department, Rice University, Houston, TX 77098, USA.
| | - N P Lemoine
- Department of Biological Sciences, Marquette University, Milwaukee, WI 53233, USA; Department of Zoology, Milwaukee Public Museum, Milwaukee, WI 53233, USA
| | - C Cook
- Department of Biological Sciences, Marquette University, Milwaukee, WI 53233, USA
| | - A M S Correa
- BioSciences Department, Rice University, Houston, TX 77098, USA
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4
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Pearman JK, Thomson-Laing G, Thomson-Laing J, Thompson L, Waters S, Reyes L, Howarth JD, Vandergoes MJ, Wood SA. The Role of Environmental Processes and Geographic Distance in Regulating Local and Regionally Abundant and Rare Bacterioplankton in Lakes. Front Microbiol 2022; 12:793441. [PMID: 35250905 PMCID: PMC8888906 DOI: 10.3389/fmicb.2021.793441] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2021] [Accepted: 12/21/2021] [Indexed: 01/04/2023] Open
Abstract
Bacteria are vital components of lake systems, driving a variety of biogeochemical cycles and ecosystem services. Bacterial communities have been shown to have a skewed distribution with a few abundant species and a large number of rare species. The contribution of environmental processes or geographic distance in structuring these components is uncertain. The discrete nature of lakes provides an ideal test case to investigate microbial biogeographical patterns. In the present study, we used 16S rRNA gene metabarcoding to examine the distribution patterns on local and regional scales of abundant and rare planktonic bacteria across 167 New Zealand lakes covering broad environmental gradients. Only a few amplicon sequence variants (ASVs) were abundant with a higher proportion of rare ASVs. The proportion of locally abundant ASVs was negatively correlated with the percentage of high productivity grassland in the catchment and positively with altitude. Regionally rare ASVs had a restricted distribution and were only found in one or a few lakes. In general, regionally abundant ASVs had higher occupancy rates, although there were some with restricted occupancy. Environmental processes made a higher contribution to structuring the regionally abundant community, while geographic distances were more important for regionally rare ASVs. A better understanding of the processes structuring the abundance and distribution of bacterial communities within lakes will assist in understand microbial biogeography and in predicting how these communities might shift with environmental change.
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Affiliation(s)
- John K Pearman
- Coastal and Freshwater Group, Cawthron Institute, Nelson, New Zealand
| | | | | | - Lucy Thompson
- Coastal and Freshwater Group, Cawthron Institute, Nelson, New Zealand
| | - Sean Waters
- Coastal and Freshwater Group, Cawthron Institute, Nelson, New Zealand
| | | | - Jamie D Howarth
- School of Geography, Environment and Earth Sciences, University of Victoria, Wellington, New Zealand
| | | | - Susanna A Wood
- Coastal and Freshwater Group, Cawthron Institute, Nelson, New Zealand
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5
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Briscoe AG, Nichols S, Hartikainen H, Knipe H, Foster R, Green AJ, Okamura B, Bass D. High-Throughput Sequencing of faeces provides evidence for dispersal of parasites and pathogens by migratory waterbirds. Mol Ecol Resour 2021; 22:1303-1318. [PMID: 34758191 DOI: 10.1111/1755-0998.13548] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2021] [Revised: 10/26/2021] [Accepted: 11/02/2021] [Indexed: 11/28/2022]
Abstract
Examination of faecal material has demonstrated how a broad range of organisms are distributed by bird movements. Such research has largely focused on dispersal of plant seeds by frugivores and of freshwater organisms by waterbirds. However, with few exceptions (e.g. avian influenza, Ebola virus), there is a dearth of evidence for transport of parasites and pathogens. High-throughput sequencing methods now provide a powerful means of addressing this knowledge gap by elucidating faecal contents in unprecedented detail. We collected faeces excreted by a range of migratory waterbirds in south-west Spain and pooled faecal DNA to create libraries reflective of feeding behavior. We created sets of libraries using high-throughput metagenomic and amplicon sequencing. For the latter we employed two sets of primers to broadly target the V4 region of the 18S rRNA gene (one set amplifying the region across all eukaryotes, the other excluding amplification of metazoans). Libraries revealed a wide diversity of eukaryotes, including parasites of the faecal producers themselves, parasites of food items, or those incidentally ingested. We also detected novel microbial eukaryotic taxa and found that parasite assemblage profiles were relatively distinct. Comparing the performance of the methods used supports their joint use for future studies of diversity and abundance. Because viable stages of many parasites are likely to be present in faeces, our results suggest significant levels of bird-mediated dispersal of parasites (both from avian and other hosts). Our methods revealed much hidden biodiversity, and allowed identification of the individuals who produced the faecal samples to species level, facilitating the study of interaction networks.
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Affiliation(s)
- Andrew G Briscoe
- Department of Life Sciences, Natural History Museum, London, United Kingdom.,Core Research Laboratories, Natural History Museum, London, United Kingdom
| | - Sarah Nichols
- Department of Life Sciences, Natural History Museum, London, United Kingdom
| | - Hanna Hartikainen
- Department of Life Sciences, Natural History Museum, London, United Kingdom.,Eawag and Institute for Integrative Biology, Eidgenössische Technische Hochschule (ETH), Zurich, Switzerland
| | - Hazel Knipe
- Department of Life Sciences, Natural History Museum, London, United Kingdom
| | - Rachel Foster
- Department of Life Sciences, Natural History Museum, London, United Kingdom
| | - Andy J Green
- Department of Wetland Ecology, Estación Biológica de Doñana, EBD-CSIC, 41092, Sevilla, Spain
| | - Beth Okamura
- Department of Life Sciences, Natural History Museum, London, United Kingdom
| | - David Bass
- Department of Life Sciences, Natural History Museum, London, United Kingdom.,Centre for Environment, Aquaculture and Fisheries Science (Cefas), Weymouth, UK
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6
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Rengefors K, Gollnisch R, Sassenhagen I, Härnström Aloisi K, Svensson M, Lebret K, Čertnerová D, Cresko WA, Bassham S, Ahrén D. Genome-wide single nucleotide polymorphism markers reveal population structure and dispersal direction of an expanding nuisance algal bloom species. Mol Ecol 2021; 30:912-925. [PMID: 33386639 DOI: 10.1111/mec.15787] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2020] [Revised: 12/04/2020] [Accepted: 12/18/2020] [Indexed: 02/06/2023]
Abstract
Species invasion and range expansion are currently under scrutiny due to increasing anthropogenic impact on the natural environment. This is also true for harmful algal blooms, which have been reported to have increased in frequency. However, this research is challenging due to the ephemeral nature, small size and mostly low concentrations of microalgae in the environment. One such species is the nuisance microalga Gonyostomum semen (Raphidophyceae), which has increased in occurrence in northern Europe in recent decades. The question of whether the species has expanded its habitat range or if it was already present in the lakes but was too rare to be detected remains unanswered. The aim of the present study was to determine the genetic structure and dispersal pathways of G. semen using RAD (restriction-site-associated DNA) tag sequencing. For G. semen, which has a huge genome (32 Gbp), we faced particular challenges, but were nevertheless able to recover over 1000 single nucleotide polymorphisms at high coverage. Our data revealed a distinct population genetic structure, demonstrating a divide of western and eastern populations that probably represent different lineages. Despite significant genetic differentiation among lakes, we found only limited isolation-by-distance. While we had expected a pattern of recent expansion northwards, the data demonstrated gene flow from the northeast/east towards the southwest/west. This genetic signature suggests that the observed gene flow may be due to dispersal by autumn migratory birds, which act as dispersal vectors of resistant resting propagules that form at the end of the G. semen blooms.
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Affiliation(s)
| | | | - Ingrid Sassenhagen
- Department of Biology, Lund University, Lund, Sweden.,Department of Ecology and Genetics, Uppsala University, Uppsala, Sweden
| | - Karolina Härnström Aloisi
- Department of Biology, Lund University, Lund, Sweden.,Nordic Genetic Resource Centre (NordGen), Alnarp, Sweden
| | | | - Karen Lebret
- Department of Biology, Lund University, Lund, Sweden
| | - Dora Čertnerová
- Department of Botany, Faculty of Science, Charles University, Prague, Czech Republic
| | - William A Cresko
- Institute of Ecology and Evolution, University of Oregon, Eugene, OR, USA
| | - Susan Bassham
- Institute of Ecology and Evolution, University of Oregon, Eugene, OR, USA
| | - Dag Ahrén
- Department of Biology, National Bioinformatics Infrastructure Sweden (NBIS), SciLifeLab, Lund, Sweden
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7
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Mestre M, Höfer J. The Microbial Conveyor Belt: Connecting the Globe through Dispersion and Dormancy. Trends Microbiol 2020; 29:482-492. [PMID: 33281016 DOI: 10.1016/j.tim.2020.10.007] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2020] [Revised: 10/15/2020] [Accepted: 10/20/2020] [Indexed: 12/21/2022]
Abstract
Despite the recent increase in knowledge concerning microorganisms, the processes determining their global distribution and functioning have not been disentangled. Microbial dormant stages are adapted to endure specific adverse conditions related to their dispersion path, suggesting that dispersion is not entirely a stochastic process. Long-term dormancy enhances microbial dispersion, promoting the ubiquity of microorganisms. The evidence leads us to propose that there is a global, recurrent, and spatially cyclical dispersion of microorganisms that we have called the Microbial Conveyor Belt. These dispersion cycles directly influence the distribution of microorganisms, the global cycling of inorganic and organic matter, and thus the Earth system's functioning.
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Affiliation(s)
- Mireia Mestre
- Centro de Investigación Oceanográfica COPAS Sur-Austral, Departamento de Oceanografía, Universidad de Concepción, Concepción, Chile; Centro FONDAP de Investigación Dinámica de Ecosistemas Marinos de Altas Latitudes (IDEAL), Valdivia, Chile.
| | - Juan Höfer
- Centro FONDAP de Investigación Dinámica de Ecosistemas Marinos de Altas Latitudes (IDEAL), Valdivia, Chile; Escuela de Ciencias del Mar, Pontificia Universidad Católica de Valparaíso, Valparaíso, Chile; Centro de Investigación y Formación San Ignacio de Huinay, Huinay, Chile.
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8
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Gottschling M, Czech L, Mahé F, Adl S, Dunthorn M. The Windblown: Possible Explanations for Dinophyte DNA in Forest Soils. J Eukaryot Microbiol 2020; 68:e12833. [PMID: 33155377 DOI: 10.1111/jeu.12833] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2020] [Revised: 10/12/2020] [Accepted: 10/28/2020] [Indexed: 11/28/2022]
Abstract
Dinophytes are widely distributed in marine- and fresh-waters, but have yet to be conclusively documented in terrestrial environments. Here, we evaluated the presence of these protists from an environmental DNA metabarcoding dataset of Neotropical rainforest soils. Using a phylogenetic placement approach with a reference alignment and tree, we showed that the numerous sequencing reads that were phylogenetically placed as dinophytes did not correlate with taxonomic assignment, environmental preference, nutritional mode, or dormancy. All the dinophytes in the soils are rather windblown dispersal units of aquatic species and are not biologically active residents of terrestrial environments.
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Affiliation(s)
- Marc Gottschling
- Department Biologie, Systematische Botanik und Mykologie, GeoBio-Center, Ludwig-Maximilians-Universität München, Munich, D-80638, Germany
| | - Lucas Czech
- Computational Molecular Evolution Group, Heidelberg Institute for Theoretical Studies, Heidelberg, D-69118, Germany.,Department of Plant Biology, Carnegie Institution for Science, Stanford, California, 94305, USA
| | - Frédéric Mahé
- CIRAD, UMR BGPI, Montpellier, F-34398, France.,BGPI, Université de Montpellier, CIRAD, IRD, Montpellier SupAgro, , Montpellier, France
| | - Sina Adl
- Department of Soil Sciences, College of Agriculture and Bioresources, University of Saskatchewan, Saskatoon, SK, S7N 5A8, Canada
| | - Micah Dunthorn
- Eukaryotic Microbiology, Faculty of Biology, Universität Duisburg-Essen, Essen, D-45141, Germany.,Centre for Water and Environmental Research (ZWU), Universität Duisburg-Essen, Essen, D-45141, Germany
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9
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Mechanisms protect airborne green microalgae during long distance dispersal. Sci Rep 2020; 10:13984. [PMID: 32814827 PMCID: PMC7438330 DOI: 10.1038/s41598-020-71004-y] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2020] [Accepted: 08/05/2020] [Indexed: 11/08/2022] Open
Abstract
Viable microalgae occur in the air. Whether they can survive the stresses such as UV, desiccation and freezing temperatures at high altitudes during long distance dispersal is rarely studied. If yes, what mechanisms confer the tolerance? Four freshwater airborne green microalgae were isolated from Dongsha Atoll in the South China Sea, classified as Scenedesmus sp. DSA1, Coelastrella sp. DSA2, Coelastrella sp. DSA3 and Desmodesmus sp. DSA6 based on their morphologies and ITS sequences. Their survival rates under UV stress were tightly correlated with their cell wall thickness. All the four airborne green microalgae survived the air-dry stress on benchtop followed by − 20 °C freeze–desiccation stress for 4 weeks, but not the two waterborne green microalgae Desmodesmus sp. F5 and Neodesmus sp. UTEX 2219-4 used as controls. Three of the four airborne microalgae survived the lyophilization treatment, excluding Desmodesmus sp. DSA6 and the two waterborne microalgae. The four airborne microalgae produced carotenoids under prolonged stress conditions, which might help detoxify the reactive oxygen species generated under environmental stresses and shield from the high-light stress in the air. Characterization of these airborne microalgae may help answer how the descendants of green algae survived on the land about 450 MYA.
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10
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Lee B, Park MG. Distribution and genetic diversity of the toxic benthic dinoflagellate genus Ostreopsis in Korea. HARMFUL ALGAE 2020; 96:101820. [PMID: 32560838 DOI: 10.1016/j.hal.2020.101820] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/24/2019] [Revised: 04/16/2020] [Accepted: 04/29/2020] [Indexed: 06/11/2023]
Abstract
Species belonging to the toxic dinoflagellate genus Ostreopsis are widespread, occurring from tropical to temperate waters. As mainly benthic/epiphytic species, they would be expected to show distinct geographical patterns. In this study, ribosomal DNA (rDNA) sequences from partial nuclear LSU D8-D10, 5.8S, and ITS regions were determined for 169 isolates of Ostreopsis species collected from three coastal sites (i.e., Jeju Island, Chuja Island, and Pohang) within Korea. The phylogenetic tree inferred from the LSU rDNA D8-D10 sequences showed that Korean Ostreopsis species corresponded to either Ostreopsis sp. 1 or sp. 6, with Ostreopsis sp. 1 being relatively predominant regarding their distribution. While Ostreopsis sp. 1 occurred throughout all the three sampling sites within Korea, Ostreopsis sp. 6 was confined to the northern part of Jeju Island. When further investigated, the genetic diversity of Ostreopsis sp. 1 in Korea based on ITS sequences showed a total of 21 haplotypes. The presumed ancestral haplotype H3, was also present in the Japanese and Russian populations of Ostreopsis sp. 1. Although the overall demographic history of all the Korean populations of Ostreopsis sp. 1 could not be clearly identified, probably due to a mixture of different regional demographic patterns within Korea, each Ostreopsis sp. 1 population showed a characteristic demographic pattern at a regional scale. While the Jeju Island Ostreopsis sp. 1 population showed a signal in agreement with population equilibrium, the Chuja Island and Pohang Ostreopsis sp. 1 populations showed distribution patterns that are expected in a sudden population expansion model. The results from this study provide a basis for a better understanding of the distribution and genetic structure of the Asian Ostreopsis sp. 1 populations.
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Affiliation(s)
- Bora Lee
- LOHABE, Department of Oceanography, Chonnam National University, Gwangju 61186, Republic of Korea
| | - Myung Gil Park
- LOHABE, Department of Oceanography, Chonnam National University, Gwangju 61186, Republic of Korea.
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11
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Sildever S, Jerney J, Kremp A, Oikawa H, Sakamoto S, Yamaguchi M, Baba K, Mori A, Fukui T, Nonomura T, Shinada A, Kuroda H, Kanno N, Mackenzie L, Anderson DM, Nagai S. Genetic relatedness of a new Japanese isolates of Alexandrium ostenfeldii bloom population with global isolates. HARMFUL ALGAE 2019; 84:64-74. [PMID: 31128814 PMCID: PMC6540814 DOI: 10.1016/j.hal.2019.02.005] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/28/2018] [Revised: 01/12/2019] [Accepted: 02/02/2019] [Indexed: 05/13/2023]
Abstract
In recent years, blooms of toxic Alexandrium ostenfeldii strains have been reported from around the world. In 2013, the species formed a red tide in a shallow lagoon in western Japan, which was the first report of the species in the area. To investigate the genetic relatedness of Japanese A. ostenfeldii and global isolates, the full-length SSU, ITS and LSU sequences were determined, and phylogenetic analyses were conducted for isolates from western and northern Japan and from the Baltic Sea. Genotyping and microsatellite sequence comparison were performed to estimate the divergence and connectivity between the populations from western Japan and the Baltic Sea. In all phylogenetic analyses, the isolates from western Japan grouped together with global isolates from shallow and low saline areas, such as the Baltic Sea, estuaries on the east coast of U.S.A. and from the Bohai Sea, China. In contrast, the isolates from northern Japan formed a well-supported separate group in the ITS and LSU phylogenies, indicating differentiation between the Japanese populations. This was further supported by the notable differentiation between the sequences of western and northern Japanese isolates, whereas the lowest differentiation was found between the western Japanese and Chinese isolates. Microsatellite genotyping revealed low genetic diversity in the western Japanese population, possibly explained by a recent introduction to the lagoon from where it was detected. The red tide recorded in the shallow lagoon followed notable changes in the salinity of the waterbody and phytoplankton composition, potentially facilitating the bloom of A. ostenfeldii.
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Affiliation(s)
- Sirje Sildever
- National Research Institute of Fisheries Science, Yokohama, Kanagawa, 236-8648, Japan
| | - Jacqueline Jerney
- Finnish Environment Institute, Marine Research Centre, Agnes Sjöberginkatu 2, 00790 Helsinki, Finland
| | - Anke Kremp
- Finnish Environment Institute, Marine Research Centre, Agnes Sjöberginkatu 2, 00790 Helsinki, Finland
| | - Hiroshi Oikawa
- National Research Institute of Fisheries Science, Yokohama, Kanagawa, 236-8648, Japan
| | - Setsuko Sakamoto
- National Research Institute of Fisheries and Environment of Inland Sea, Hatsukaichi, Hiroshima, 739-0452, Japan
| | | | - Katsuhisa Baba
- Hokkaido Research Organization, Fisheries Research Department, Central Fisheries Research Institute, Yoichi, Hokkaido, 046-855, Japan
| | - Akihiro Mori
- Tottori Prefecture Water Environment Management Division, 1-220 Higashimachi, Tottori 680-8570, Japan
| | - Toshinori Fukui
- Tottori Prefectural Fisheries Research Center, 1166 Ishiwaki, Yurihama-cho, Tohaku-gun, Tottori Prefecture, 689-0602, Japan
| | - Takumi Nonomura
- Tottori Prefectural Fisheries Research Center, 1166 Ishiwaki, Yurihama-cho, Tohaku-gun, Tottori Prefecture, 689-0602, Japan
| | - Akiyoshi Shinada
- Central Fisheries Research Institute, 238 Hamanaka, Yoichi, Hokkaido, 046-8555, Japan
| | - Hiroshi Kuroda
- Hokkaido National Fisheries Research Institute, 116 Katsurakoi, Kushiro, Hokkaido, 085-0802, Japan
| | - Nanako Kanno
- National Research Institute of Fisheries Science, Yokohama, Kanagawa, 236-8648, Japan
| | - Lincoln Mackenzie
- Cawthron Institute, 98 Halifax Street East, Nelson 7010, New Zealand
| | - Donald M Anderson
- Woods Hole Oceanographic Institution, Woods Hole, MA, 02543-1050 USA
| | - Satoshi Nagai
- National Research Institute of Fisheries Science, Yokohama, Kanagawa, 236-8648, Japan.
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