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Abstract
Long-read sequencing of a marine stramenopile genome yields a trove of insights into protist genomics and solves a 50-year-old viral mystery.
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Affiliation(s)
- Frank O Aylward
- Department of Biological Sciences, Virginia Tech, Blacksburg, VA 24061, USA; Center for Emerging, Zoonotic, and Arthropod-Borne Pathogens, Blacksburg, VA 24061, USA.
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2
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Collier JL, Rest JS, Gallot-Lavallée L, Lavington E, Kuo A, Jenkins J, Plott C, Pangilinan J, Daum C, Grigoriev IV, Filloramo GV, Novák Vanclová AMG, Archibald JM. The protist Aurantiochytrium has universal subtelomeric rDNAs and is a host for mirusviruses. Curr Biol 2023; 33:5199-5207.e4. [PMID: 37913769 DOI: 10.1016/j.cub.2023.10.009] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2023] [Revised: 09/08/2023] [Accepted: 10/06/2023] [Indexed: 11/03/2023]
Abstract
Viruses are the most abundant biological entities in the world's oceans, where they play important ecological and biogeochemical roles. Metagenomics is revealing new groups of eukaryotic viruses, although disconnected from known hosts. Among these are the recently described mirusviruses, which share some similarities with herpesviruses.1 50 years ago, "herpes-type" viral particles2 were found in a thraustochytrid member of the labyrinthulomycetes, a diverse group of abundant and ecologically important marine eukaryotes,3,4 but could not be further characterized by methods then available. Long-read sequencing has allowed us to connect the biology of mirusviruses and thraustochytrids. We sequenced the genome of the genetically tractable model thraustochytrid Aurantiochytrium limacinum ATCC MYA-1381 and found that its 26 linear chromosomes have an extraordinary configuration. Subtelomeric ribosomal DNAs (rDNAs) found at all chromosome ends are interspersed with long repeated sequence elements denoted as long repeated-telomere and rDNA spacers (LORE-TEARS). We identified two genomic elements that are related to mirusvirus genomes. The first is a ∼300-kbp episome (circular element 1 [CE1]) present at a high copy number. Strikingly, the second, distinct, mirusvirus-like element is integrated between two sets of rDNAs and LORE-TEARS at the left end of chromosome 15 (LE-Chr15). Similar to metagenomically derived mirusviruses, these putative A. limacinum mirusviruses have a virion module related to that of herpesviruses along with an informational module related to nucleocytoplasmic large DNA viruses (NCLDVs). CE1 and LE-Chr15 bear striking similarities to episomal and endogenous latent forms of herpesviruses, respectively, and open new avenues of research into marine virus-host interactions.
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Affiliation(s)
- Jackie L Collier
- School of Marine and Atmospheric Sciences, Stony Brook University, Nicolls Road, Stony Brook, NY 11794, USA.
| | - Joshua S Rest
- Department of Ecology and Evolution, Stony Brook University, Nicolls Road, Stony Brook, NY 11794, USA.
| | - Lucie Gallot-Lavallée
- Department of Biochemistry & Molecular Biology, Dalhousie University, College Street, Halifax, NS B3H 4R2, Canada
| | - Erik Lavington
- Department of Ecology and Evolution, Stony Brook University, Nicolls Road, Stony Brook, NY 11794, USA
| | - Alan Kuo
- U.S. Department of Energy Joint Genome Institute, Lawrence Berkeley National Laboratory, Cyclotron Road, Berkeley, CA 94720, USA
| | - Jerry Jenkins
- U.S. Department of Energy Joint Genome Institute, Lawrence Berkeley National Laboratory, Cyclotron Road, Berkeley, CA 94720, USA; HudsonAlpha Institute for Biotechnology, Genome Way Northwest, Huntsville, AL 35806, USA
| | - Chris Plott
- U.S. Department of Energy Joint Genome Institute, Lawrence Berkeley National Laboratory, Cyclotron Road, Berkeley, CA 94720, USA; HudsonAlpha Institute for Biotechnology, Genome Way Northwest, Huntsville, AL 35806, USA
| | - Jasmyn Pangilinan
- U.S. Department of Energy Joint Genome Institute, Lawrence Berkeley National Laboratory, Cyclotron Road, Berkeley, CA 94720, USA
| | - Chris Daum
- U.S. Department of Energy Joint Genome Institute, Lawrence Berkeley National Laboratory, Cyclotron Road, Berkeley, CA 94720, USA
| | - Igor V Grigoriev
- U.S. Department of Energy Joint Genome Institute, Lawrence Berkeley National Laboratory, Cyclotron Road, Berkeley, CA 94720, USA; Department of Plant and Microbial Biology, University of California Berkeley, University Avenue, Berkeley, CA 94720, USA
| | - Gina V Filloramo
- Department of Biochemistry & Molecular Biology, Dalhousie University, College Street, Halifax, NS B3H 4R2, Canada
| | | | - John M Archibald
- Department of Biochemistry & Molecular Biology, Dalhousie University, College Street, Halifax, NS B3H 4R2, Canada
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Paul-Pont I, Dhand NK, Whittington RJ. Spatial distribution of mortality in Pacific oysters Crassostrea gigas: reflection on mechanisms of OsHV-1 transmission. DISEASES OF AQUATIC ORGANISMS 2013; 105:127-138. [PMID: 23872856 DOI: 10.3354/dao02615] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
The ostreid herpesvirus OsHV-1 has the potential to devastate Pacific oyster Crassostrea gigas culture in Australia as it has done in many other countries, highlighting the need for a better understanding of disease expression and transmission. The aim of this study was to assess the spatial distribution of OsHV-1-associated mortalities in one of only two infected areas in Australia, Woolooware Bay (Botany Bay, New South Wales). In October 2011, healthy sentinel Pacific oysters were placed in 3 different locations at 3 different tidal levels, and OsHV-1 associated mortalities were closely monitored over 7 mo. The outbreak started in November 2011, and the disease remained active until April 2012. Three major mortality events were detected. Rather than being a propagating epizootic, it appeared that most oysters were infected from a common environmental source. The distribution of OsHV-1-associated mortalities was spatially clustered, highly variable and clearly dependent on the age of oysters and their position in the water column. Non-random distribution of mortalities at macro scale (sites several km apart) and micro scale (within rearing trays), and vertical clustering patterns in the water column are discussed in regard to factors known to influence mechanism of disease transmission in aquatic environments (hydrodynamics, physical disturbances, host density/distribution, and variations of environmental parameters). A new hypothesis proposing that OsHV-1 may be carried through water by particles, possibly plankton, is also suggested to explain the patchy distribution of mortalities in Woolooware Bay.
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Affiliation(s)
- Ika Paul-Pont
- Faculty of Veterinary Science, The University of Sydney, Camden, New South Wales, Australia.
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Takao Y, Mise K, Nagasaki K, Okuno T, Honda D. Complete nucleotide sequence and genome organization of a single-stranded RNA virus infecting the marine fungoid protist Schizochytrium sp. J Gen Virol 2006; 87:723-733. [PMID: 16476996 DOI: 10.1099/vir.0.81204-0] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The complete nucleotide sequence of the genomic RNA of a marine fungoid protist-infecting virus (Schizochytrium single-stranded RNA virus; SssRNAV) has been determined. The viral RNA is single-stranded with a positive sense and is 9018 nt in length [excluding the 3′ poly(A) tail]. It contains two long open reading frames (ORFs), which are separated by an intergenic region of 92 nt. The 5′ ORF (ORF1) is preceded by an untranslated leader sequence of 554 nt. The 3′ large ORF (ORF2) and an additional ORF (ORF3) overlap ORF2 by 431 nt and are followed by an untranslated region of 70 nt [excluding the 3′ poly(A) tail]. The deduced amino acid sequences of ORF1 and ORF2 products show similarity to non-structural and structural proteins of dicistroviruses, respectively. However, Northern blot analysis suggests that SssRNAV synthesizes subgenomic RNAs to translate ORF2 and ORF3, showing that the translation mechanism of downstream ORFs is distinct from that of dicistroviruses. Furthermore, although considerable similarities were detected by using a blast genome database search, phylogenetic analysis based on both the nucleotide and amino acid sequences of the putative RNA-dependent RNA polymerase (RdRp) and the RNA helicase suggests that SssRNAV is phylogenetically distinct from other virus families. Therefore, it is concluded that SssRNAV is not a member of any currently defined virus family and belongs to a novel, unrecognized virus group.
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Affiliation(s)
- Yoshitake Takao
- Department of Biology, Faculty of Science and Engineering, Konan University, 8-9-1 Okamoto, Higashinada, Kobe 658-8501, Japan
| | - Kazuyuki Mise
- Laboratory of Plant Pathology, Graduate School of Agriculture, Kyoto University, Kyoto, Japan
| | - Keizo Nagasaki
- Harmful Algal Bloom Division, National Research Institute of Fisheries and Environment of Inland Sea, Fisheries Research Agency, Hiroshima, Japan
| | - Tetsuro Okuno
- Laboratory of Plant Pathology, Graduate School of Agriculture, Kyoto University, Kyoto, Japan
| | - Daiske Honda
- Department of Biology, Faculty of Science and Engineering, Konan University, 8-9-1 Okamoto, Higashinada, Kobe 658-8501, Japan
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Takao Y, Nagasaki K, Mise K, Okuno T, Honda D. Isolation and characterization of a novel single-stranded RNA Virus infectious to a marine fungoid protist, Schizochytrium sp. (Thraustochytriaceae, Labyrinthulea). Appl Environ Microbiol 2005; 71:4516-22. [PMID: 16085844 PMCID: PMC1183295 DOI: 10.1128/aem.71.8.4516-4522.2005] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Thraustochytrids are cosmopolitan osmoheterotrophic microorganisms that play important roles as decomposers, producers of polyunsaturated fatty acids, and pathogens of mollusks, especially in coastal ecosystems. SssRNAV, a novel single-stranded RNA (ssRNA) virus infecting the marine fungoid protist Schizochytrium sp. (Labyrinthulea, Thraustochytriaceae) was isolated from the coastal water of Kobe Harbor, Japan, in July 2000, and its basic characteristics were examined. The virus particle is icosahedral, lacks a tail, and is ca. 25 nm in diameter. SssRNAV formed crystalline arrays and random assemblies within the cytoplasm of host cells, and it was also concentrated along the intracellular membrane structures. By means of one-step growth experiments, the lytic cycle and the burst size were estimated to be <8 h and 5.8 x 10(3) to 6.4 x 10(4) infectious units per host cell, respectively. SssRNAV had a single molecule of ssRNA that was approximately 10.2 kb long, three major proteins (37, 34, and 32 kDa), and two minor proteins (80 and 18 kDa). Although SssRNAV was considered to have some similarities with invertebrate viruses belonging to the family Dicistroviridae based on its partial nucleotide sequence, further genomic analysis is required to determine the detailed classification and nomenclature of SssRNAV. Our results indicate that viral infection is one of the significant factors controlling the dynamics of thraustochytrids and provide new insights into understanding the ecology of these organisms.
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Affiliation(s)
- Yoshitake Takao
- Department of Biology, Faculty of Science and Engineering, Konan University, 8-9-1 Okamoto, Higashinada, Kobe 658-8501, Japan
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Jensen CJP, Allison RF, Adams GC. Purification and characterization of a virus-like particle of Leucostoma persoonii. Mycologia 1995. [DOI: 10.1080/00275514.1995.12026551] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
Affiliation(s)
- Carolyn J. P. Jensen
- Department of Botany and Plant Pathology, Michigan State University, East Lansing, Michigan 48824-1312
| | - Richard F. Allison
- Department of Botany and Plant Pathology, Michigan State University, East Lansing, Michigan 48824-1312
| | - Gerard C. Adams
- Department of Botany and Plant Pathology, Michigan State University, East Lansing, Michigan 48824-1312
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Abstract
In 1981, herpesviruses were classified by the International Committee of Taxonomy of Viruses (ICTV, 1) inside the herpesviridae family. Progress in biotechnology and molecular biology during the last 10 yr, has permitted the characterization of new viruses and genomic structures. The objective of this paper is to collect the data found in the literature since 1981, to actualize the description of herpesviridae family.
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Affiliation(s)
- T Foulon
- Laboratoire de virologie de l'herpes, Institut de Recherches Scientifiques sur le Cancer (IRSC), Villejuif, France
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