Raphidovirus

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Raphidovirus
Systematics
Classification : Viruses
Area : Varidnaviria
Empire : Bamfordvirae
Phylum : Nucleocytoviricota
Class : Megaviricetes
Order : Algavirales
Family : Phycodnaviridae
Genre : Raphidovirus
Type : Heterosigma akashiwo virus 01
(HaV01) 
Taxonomic characteristics
Genome : dsDNA linear
Baltimore : Group 1
Symmetry : icosahedral
Cover : available
Scientific name
Raphidovirus
Left
NCBI  Taxonomy: 573012 (genus)
ViralZone ( ExPASy , SIB): 624 (genus)
ICTV Taxon History: 201854330 (species)

Raphidovirus (often misspelled as Rhaphidovirus ) is a genus of virus from the Phycodnaviridae familywith algae as natural hosts. The genus wasofficially recognizedby the International Committee on Taxonomy of Viruses (ICTV)as of July 2017, with a single species, the type species Heterosigma akashiwo virus 01 ( HaV01 , also HaV-01 ). HaV was first isolated and scientifically described in 1997; it infects the unicellular alga Heterosigma akashiwo ( Raphidophyceae ). H. akashiwo forms algal blooms and iswidespreadin temperate and neritic waters.

HaV specifically infects H. akashiwo and no other marine phytoplankton species tested . The mechanisms underlying this specificity are not exactly known. Tomaru et al. suggested in 2008 that virus-host specificity may be caused by unique interactions between a viral ligand and a host receptor.

Various other types of viruses that infect H. akashiwo have also been isolated and should not be confused with HaV, such as the heterosigma akashiwo RNA virus (HaRNAV) and the heterosigma akashiwo nuclear inclusion virus (HaNIV).

construction

The virus particles of raphidovirus are enveloped and have a rounded icosahedral geometry with T = 169 symmetry . Their diameter is 100–220  nm . The genome is linear and approximately 295  kb long.

  • In the type species Heterosigma akashiwo virus 01 (HaV-1), the virion diameter is 201 nm, the genome length 275 bp and the GC content is 30.4%.
  • When HAV-1 isolate HaV53 the exact length genome is 274,793 bp and 246 are predicted Proteinw coded .

Propagation cycle

The virus replication is nukleozytoplasmatisch and follows the DNA strand-displacement model ( English DNA beach displacement model ). The method of transcription is based on DNA. The virus leaves the host cell by lysis by means of lytic phospholipids . The transmission occurs through passive diffusion.

In a study by Nagasaki et al. virus particles (virions) were found in the cytoplasm of the host 24 hours after infection . The latency or lysogenic cycle was estimated to be 30 to 33 hours, with the average burst size (number of virus particles produced after lysis) being 770 per cell.

Systematics

According to ICTV (as of July 2019, Master Species List # 34 2018b v1):

  • Genus: Raphidovirus
  • Species: Heterosigma akashiwo virus 01 (HaV-1, type species)
  • Isolate Heterosigma akashiwo virus 01 isolate HaV53

HaV01 possibly forms a fourth branch of a family group ( clade ) in addition to the (extended) Mimiviridae (alias Megaviridae ), the Phycodnaviridae of the chlorovirus type and the Phycodnaviridae of the Phaeovirus / coccolithovirus type . The family group with this size was raised to the rank of a class by the ICTV with the new Master Species List # 35 in March 2020 with the designation Megaviricetes . Koonin and Yutin (2018) also see HaV01 (i.e. the genus Raphidovirus ) on a par with the extended Mimiviridae (here called Mimivirus-like viruses , officially designated by the ICTV in March 2020 as the order Imitervirales ), the chlorovirus-like viruses ( Phycodnaviruses in the narrower sense with the genera Chlorovirus , Prasinovirus including Yellowstone Lake Phycodnavirus 1 to 3 and Dishui Lake Phycodnavirus 1 ), the Coccolitho-Phaeovirus-like viruses (genera Coccolithovirus and Phaeovirus ).

Individual evidence

  1. ↑ a b c d e ICTV: ICTV Master Species List 2019.v1 , New MSL including all taxa updates since the 2018b release, March 2020 (MSL # 35)
  2. ↑ a b c Viral Zone: Raphidovirus . ExPASy. Retrieved July 12, 2019.
  3. ↑ a b ICTV: Virus Taxonomy: 2014 Release . Retrieved July 12, 2019.
  4. ↑ Christopher R. Schvarcz, Grieg F. Steward: A giant virus infecting green algae encodes key fermentation genes , in: Virology Volume 518, May 2018, pp. 423-433, doi: 10.1016 / j.virol.2018.03.010
  5. ↑ a b c d Yuji Tomaru, Yoko Shirai, Keizo Nagasaki: Ecology, physiology and genetics of a phycodnavirus infecting the noxious bloom-forming raphidophyte Heterosigma akashiwo . In: Fisheries Science . 74, No. 4, August 1, 2008, pp. 701-711. doi : 10.1111 / j.1444-2906.2008.01580.x .
  6. ↑ Fumito Maruyama, Shoko Ueki: Evolution and Phylogeny of Large DNA Viruses, Mimiviridae and Phycodnaviridae Including Newly Characterized Heterosigma akashiwo Virus . In: Frontiers in Microbiology . 7, 2016, p. 1942. doi : 10.3389 / fmicb.2016.01942 . PMID 27965659 . PMC 5127864 (free full text).
  7. ↑ Vera Tai, Janice E Lawrence, Andrew S Lang, Amy M Chan, Alexander I Culley, Curtis A Suttle: Characterization of HaRNAV, a single-stranded RNA virus causing lysis of Heterosigma akashiwo (Raphidophyceae) . In: Journal of Phycology . 39, No. 2, 2003, pp. 343-352. doi : 10.1046 / j.1529-8817.2003.01162.x .
  8. ^ A b Janice E. Lawrence, Corina PD Brussaard, Curtis A. Suttle: Virus-Specific Responses of Heterosigma akashiwo to Infection, in: Appl Environ Microbiol, 72 (12), December 2006, pp. 7829-7834, PMC 1694243 ( free full text), PMID 17041155 , doi: 10.1128 / AEM.01207-06
  9. ↑ Proteomes - Heterosigma akashiwo RNA virus (strain SOG263) (HaRNAV) , on: UniProt
  10. ↑ Janice E Lawrence, Amy M Chan, Curtis A Suttle: A novel virus (HaNIV) causes lysis of the toxic bloom-forming alga Heterosigma akashiwo (Raphidophyceae) . In: Journal of Phycology . 37, No. 2, 2001, pp. 216-222. doi : 10.1046 / j.1529-8817.2001.037002216.x .
  11. ↑ Curtis A. Suttle: Effect of viral infection on sinking rates of Heterosigma akashiwo and its implications for bloom termination , in: Aquatic microbial ecology, 2004
  12. ↑ Jean-Michel Claverie, Chantal Abergel: Mimiviridae : An Expanding Family of Highly Diverse Large dsDNA Viruses Infecting a Wide Phylogenetic Range of Aquatic Eukaryotes]. In: Viruses . 2018 Sep; 10 (9), September 18, 2018, p. 506, doi: 10.3390 / v10090506 , PMC 6163669 (free full text), PMID 30231528 , Tab. 2
  13. ↑ Keizo Nagasaki, Kenji Tarutani, Mineo Yamaguchi: Growth Characteristics of Heterosigma akashiwo Virus and Its Possible Use as a Microbiological Agent for Red Tide Control . In: Applied and Environmental Microbiology . 65, No. 3, March 1, 1999, pp. 898-902. PMID 10049839 . PMC 91120 (free full text).
  14. ↑ NCBI: Heterosigma akashiwo virus 01 isolate HaV53 complete genome
  15. ↑ Yoshitoshi Ogura, Tetsuya Hayashi, Shoko Ueki: Complete Genome Sequence of a Phycodnavirus, Heterosigma akashiwo Virus Strain 53 , in: Microbiology, September 2016, doi: 10.1128 / genomeA.01279-16 , PubMed 27834719, PDF
  16. ↑ Fumito Maruyama, Shoko Ueki: Evolution and Phylogeny of Large DNA Viruses, Mimiviridae and Phycodnaviridae Including Newly Characterized Heterosigma akashiwo Virus , in: Front. Microbiol., November 30, 2016, doi: 10.3389 / fmicb.2016.01942 , PMC 5127864 (free full text), PMID 27965659
  17. ↑ Eugene V. Koonin, Natalya Yutin: Multiple evolutionary origins of giant viruses , in: F1000 Research, November 22, 2018, doi: 10.12688 / f1000research.16248.1 , version 1

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