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{{virusbox
{{Taxobox | color = violet
| taxon = Alphasatellitidae
| name =
| image =
| image_caption =
| virus_group = ii
| familia =
| subdivision_ranks = Species
| subdivision ='''Begomovirus group'''

[[Ageratum leaf curl Cameroon alphasatellite]]<br/>
[[Ageratum leaf curl Pakistan alphasatellite]]<br>
[[Ageratum yellow vein alphasatellite]]<br/>
[[Ageratum yellow vein India alphasatellite]]<br/>
[[Ageratum yellow vein Kenya alphasatellite]]<br/>
[[Ageratum yellow vein Pakistan alphasatellite]]<br/>
[[Ageratum yellow vein Singapore alphasatellite]]<br/>
[[Chilli leaf curl Multan alphasatellite]]<br/>
[[Cleome leaf crumple alphasatellite]]<br/>
[[Cotton leaf curl alphasatellite]]<br/>
[[Cotton leaf curl Burewala alphasatellite]]<br/>
[[Cotton leaf curl Dabwali alphasatellite]]<br/>
[[Cotton leaf curl Gezira alphasatellite]]<br/>
[[Cotton leaf curl India alphasatellite]]<br/>
[[Cotton leaf curl Multan alphasatellite]]<br/>
[[Cotton leaf curl Pakistan alphasatellite]]<br/>
[[Croton yellow vein mosaic alphasatellite]]<br/>
[[Euphorbia yellow mosaic alphasatellite]]<br/>
[[Gossypium darwinii symptomless alphasatellite]]<br/>
[[Gossypium mustelinium symptomless alphasatellite]]<br/>
[[Hollyhock crumple alphasatellite]]<br/>
[[Hollyhock yellow vein virus-associated symptomless alphasatellite ]]
[[Hibiscus leaf curl alphasatellite]]<br/>
[[Malvastrum yellow mosaic alphasatellite]]<br/>
[[Malvastrum yellow mosaic Cameroon alphasatellite]]<br/>
[[Malvastrum yellow mosaic Hainan alphasatellite]]<br/>
[[Milk vetch dwarf alphasatellite]]<br/>
[[Melon chlorotic mosaic alphasatellite]]<br/>
[[Mimosa yellow leaf curl alphasatellite]]<br/>
[[Okra leaf curl alphasatellite]]<br/>
[[Okra leaf curl Barombi alphasatellite]]<br/>
[[Okra leaf curl Burkina Faso alphasatellite]]<br/>
[[Okra leaf curl Mali alphasatellite]]<br/>
[[Okra leaf curl Tiko alphasatellite]]<br/>
[[Potato leaf curl alphasatellite]]<br/>
[[Sida leaf curl alphasatellite]]<br/>
[[Sida yellow vein alphasatellite]]<br/>
[[Sida yellow vein Vietnam alphasatellite]]<br/>
[[Tobacco curly shoot alphasatellite]]<br/>
[[Tobacco curly shoot China alphasatellite]]<br/>
[[Tomato leaf curl alphasatellite]]<br/>
[[Tomato leaf curl Cameroon alphasatellite]]<br/>
[[Tobacco leaf curl China alphasatellite]]<br/>
[[Tobacco leaf curl Pakistan alphasatellite]]<br/>
[[Tomato yellow leaf curl China alphasatellite]]<br/>
[[Tomato yellow leaf curl DNA2]]<br/>
[[Tomato yellow leaf curl Thailand alphasatellite]]<br/>
[[Tomato yellow leaf curl Yunnan alphasatellite]]<br/>
[[Verbesina encelioides leaf curl alphasatellite]]<br/>
[[Vernonia yellow vein Fujian alphasatellite]]

'''Nanoviridae group'''

[[Banana bunchy top alphasatellite]]<br/>
[[Banana bunchy top Taiwan alphasatellite]]<br/>
[[Banana bunchy top S1 alphasatellite]]<br/>
[[Banana bunchy top Vietnam alphasatellite]]<br/>
[[Banana bunchy top Y alphasatellite]]<br/>
[[Coconut foliar decay alphasatellite]]<br/>
[[Faba bean necrotic yellows alphasatellite]]<br/>
[[Milk vetch dwarf alphasatellite]]<br/>
[[Subterranean clover stunt alphasatellite]]
}}
}}


'''''Alphasatellites''''' are single stranded [[satellite virus]]es that are dependent on another [[virus]] for transmission. The genome is a single circular single strand [[DNA]] molecule. The first alphasatellites were described in 1999 and were associated with cotton leaf curl disease and Ageratum yellow vein disease.<ref name=Saunders1999>Saunders K & Stanley J (1999). A nanovirus-like DNA component associated with yellow vein disease of ''Ageratum conyzoides'': evidence for interfamilial recombination between plant DNA viruses. Virology 264: 142–152.</ref><ref name=Mansoor1999>Mansoor S, Khan SH, Bashir A, Saeed M, Zafar Y, Malik KA, Briddon R, Stanley J, Markham PG (1999) Identification of a novel circular single-stranded DNA associated with cotton leaf curl disease in Pakistan. Virology 259(1):190-199</ref> As begomoviruses are being characterised at the molecular level an increasing number of alphasatellites are being described.
'''''Alphasatellites''''' are a single-stranded DNA family of [[Satellite (biology)|satellite viruses]] that depend on the presence of another virus ([[helper virus]]es) to replicate their genomes. As such, they have minimal genomes with very low genomic redundancy. The genome is a single circular single strand [[DNA]] molecule.<ref>{{Cite journal |last1=Silva |first1=Jorge Miguel |last2=Pratas |first2=Diogo |last3=Caetano |first3=Tânia |last4=Matos |first4=Sérgio |date=2022-08-11 |title=The complexity landscape of viral genomes |journal=GigaScience |language=en |volume=11 |pages=giac079 |doi=10.1093/gigascience/giac079 |issn=2047-217X |pmc=9366995 |pmid=35950839}}</ref> The first alphasatellites were described in 1999 and were associated with cotton leaf curl disease and Ageratum yellow vein disease.<ref name=Saunders1999>{{cite journal |vauthors=Saunders K, Stanley J |title=A nanovirus-like DNA component associated with yellow vein disease of Ageratum conyzoides: evidence for interfamilial recombination between plant DNA viruses |journal=Virology |volume=264 |issue=1 |pages=142–52 |date=November 1999 |pmid=10544139 |doi=10.1006/viro.1999.9948 |doi-access=free }}</ref><ref name=Mansoor1999>{{cite journal |vauthors=Mansoor S, Khan SH, Bashir A |title=Identification of a novel circular single-stranded DNA associated with cotton leaf curl disease in Pakistan |journal=Virology |volume=259 |issue=1 |pages=190–9 |date=June 1999 |pmid=10364503 |doi=10.1006/viro.1999.9766 |display-authors=etal|doi-access=free }}</ref> As begomoviruses are being characterised at the molecular level an increasing number of alphasatellites are being described.


These viruses were earlier known as DNA 1 components.<ref name=Stanley2004>Stanley J (2004) Subviral DNAs associated with geminivirus disease complexes. Vet Microbiol 4;98(2):121-129</ref>
These viruses were earlier known as DNA 1 components.<ref name=Stanley2004>{{cite journal |author =Stanley J |title=Subviral DNAs associated with geminivirus disease complexes |journal=Vet. Microbiol. |volume=98 |issue=2 |pages=121–9 |date=February 2004 |pmid=14741124 |doi=10.1016/j.vetmic.2003.10.005}}</ref>


These viruses are generally found in the Old World. A number have been isolated from the New World but their association with their host viruses is still being studied.
These viruses are generally found in the Old World. A number have been isolated from the New World but their association with their host viruses is still being studied.
Line 80: Line 11:
==Genome==
==Genome==


The genome is between 1300 and 1400 nucleotides in length and has three conserved features: a hairpin structure, a single [[open reading frame]] (ORF) and an [[adenine]] rich region.<ref name=Briddon2004>Briddon RW, Bull SE, Amin I, Mansoor S, Bedford ID, Rishi N, Siwatch SS, Zafar Y, Abdel-Salam AM, Markham PG (2004) Diversity of DNA 1: a satellite-like molecule associated with monopartite begomovirus-DNA beta complexes. Virology ;324(2):462-474</ref>
The genome is between 1300 and 1400 nucleotides in length and has three conserved features: a hairpin structure, a single [[open reading frame]] (ORF) and an [[adenine]] rich region.<ref name=Briddon2004>{{cite journal |vauthors=Briddon RW, Bull SE, Amin I |title=Diversity of DNA 1: a satellite-like molecule associated with monopartite begomovirus-DNA beta complexes |journal=Virology |volume=324 |issue=2 |pages=462–74 |date=July 2004 |pmid=15207631 |doi=10.1016/j.virol.2004.03.041 |display-authors=etal|doi-access=free }}</ref>


The hairpin structure has a loop that includes the nonanucleotide, TAGTATTAC, which is common to nanoviruses and differs from the TAATATTAC sequence of geminiviruses by one nucleotide. In both geminiviruses and nanoviruses this sequence contains the origin of replication (''ori'') and is nicked by the rolling circle [[replication initiator protein]] to initiate viral DNA replication. On the basis of the hairpin structures alphasatellites can be divided into 5 clades.<ref name=Xie2010>Xie Y, Wu P, Liu P, Gong H, Zhou X (2010) Characterization of alphasatellites associated with monopartite begomovirus/betasatellite complexes in Yunnan, China. Virol J 7:178</ref>
The hairpin structure has a loop that includes the nonanucleotide, TAGTATTAC, which is common to nanoviruses and differs from the TAATATTAC sequence of geminiviruses by one nucleotide. In both geminiviruses and nanoviruses this sequence contains the origin of replication (''ori'') and is nicked by the rolling circle [[replication initiator protein]] to initiate viral DNA replication. On the basis of the hairpin structures alphasatellites can be divided into 5 clades.<ref name=Xie2010>{{cite journal |vauthors=Xie Y, Wu P, Liu P, Gong H, Zhou X |title=Characterization of alphasatellites associated with monopartite begomovirus/betasatellite complexes in Yunnan, China |journal=Virol. J. |volume=7 |pages=178 |year=2010 |pmid=20678232 |pmc=2922188 |doi=10.1186/1743-422X-7-178 |doi-access=free }}</ref>


The open reading frame encodes a rolling circle replication initiator protein (Rep) similar to that found in the [[nanovirus]]es. The encoded protein is 32-37 kilo[[Atomic mass unit|Dalton]] in molecular weight with ~320 amino acids. It is highly conserved with 86.3-100.0% [[amino acid]] sequence identy between isolates.
The open reading frame encodes a rolling circle replication initiator protein (Rep) similar to that found in the [[nanovirus]]es. The encoded protein is 32–37 kilo[[Dalton (unit)|dalton]] in molecular weight with ~320 amino acids. It is highly conserved with 86.3–100.0% [[amino acid]] sequence identity between isolates.{{cn|date=November 2022}}


The adenine rich region is immediately downstream of the ''rep'' gene and is approximately 153-169 [[nucleotide]]s in length with an adenine content of between 52.3-58.4%. Phylogenectic analysis of this region shows that they can be divided into three clades which correspond to those found on phylogenetic analysis of the entire genome.<ref name="Xie2010"/> This portion of the genome appears to be redundant.<ref name=Shahid2009>Shahid MS,Ali L, Andleeb S (2009) The function of the a-rich region of the alphasatellite associated with the cotton leaf curl disease in Pakistan. EurAsia J BioSci 3: 152-156</ref>
The adenine rich region is immediately downstream of the ''rep'' gene and is approximately 153–169 [[nucleotide]]s in length with an adenine content of between 52.3–58.4%. Phylogenectic analysis of this region shows that they can be divided into three clades which correspond to those found on phylogenetic analysis of the entire genome.<ref name="Xie2010"/> This portion of the genome appears to be redundant.<ref name=Shahid2009>{{cite journal |vauthors=Shahid MS, Ali L, Andleeb S |title=The function of the a-rich region of the alphasatellite associated with the cotton leaf curl disease in Pakistan |journal=EurAsia J BioSci |volume=3 |pages=152–6 |year=2009 |url=http://ejobios.com/pdf/EJOB-9-12-3,19,152-156.pdf |access-date=2014-03-08 |archive-url=https://web.archive.org/web/20140308064028/http://ejobios.com/pdf/EJOB-9-12-3,19,152-156.pdf |archive-date=2014-03-08 |url-status=dead }}</ref>


A putative second ORF in the genome of an alphasatellite virus has been described.<ref name=Romay2010>Romay G, Chirinos D, Geraud-Pouey F, Desbiez C (2010) Association of an atypical alphasatellite with a bipartite New World begomovirus. Arch Virol 155(11):1843-1847</ref> The significance of this finding (if any) is not known.
A putative second ORF in the genome of an alphasatellite virus has been described.<ref name=Romay2010>{{cite journal |vauthors=Romay G, Chirinos D, Geraud-Pouey F, Desbiez C |title=Association of an atypical alphasatellite with a bipartite New World begomovirus |journal=Arch. Virol. |volume=155 |issue=11 |pages=1843–7 |date=November 2010 |pmid=20665058 |doi=10.1007/s00705-010-0760-7 |s2cid=20039085 |url=http://prodinra.inra.fr/ft/D4763957-55A7-44B0-8FE2-E71DC412BBE3 }}</ref> The significance of this finding (if any) is not known.


Recombination occurs between alphasatellites.<ref name=Kumar2010>Kumar J, Kumar A, Roy JK, Tuli R, Khan JA (2010) Identification and molecular characterization of begomovirus and associated satellite DNA molecules infecting ''Cyamopsis tetragonoloba''. Virus Genes 41(1):118-125</ref>
Recombination occurs between alphasatellites.<ref name=Kumar2010>{{cite journal |vauthors=Kumar J, Kumar A, Roy JK, Tuli R, Khan JA |title=Identification and molecular characterization of begomovirus and associated satellite DNA molecules infecting Cyamopsis tetragonoloba |journal=Virus Genes |volume=41 |issue=1 |pages=118–25 |date=August 2010 |pmid=20405195 |doi=10.1007/s11262-010-0482-7 |s2cid=6790138 }}</ref>


==Virology==
==Virology==


There are no distinctive virons because the viral genomes are encapsidated within the coat protein of the helper virus.
There are no distinctive virions because the viral genomes are encapsidated within the coat protein of the helper virus.{{cn|date=November 2022}}


Alphasatellites associated with the [[begomovirus]]es require a begomovirus for movement in plants and insect transmission but are capable of self replication in host plants. They do not appear to cause disease in plants or to alter the course of infection by the begomovirus. They may be able to reduce the severity of an infection by the begomoviruses.<ref name=Idris2011>Idris AM, Shahid MS, Briddon RW, Khan AJ, Zhu JK, Brown JK (2011) An unusual alphasatellite associated with monopartite begomoviruses attenuates symptoms and reduces betasatellite accumulation. J Gen Virol 92(Pt 3):706-717</ref><ref name=Nawaz-Ul-Rehman2010>Nawaz-Ul-Rehman MS, Nahid N, Mansoor S, Briddon RW, Fauquet CM (2010) Post-transcriptional gene silencing suppressor activity of two non-pathogenic alphasatellites associated with a begomovirus. Virology 405(2):300-308</ref>
Alphasatellites associated with the [[begomovirus]]es require a begomovirus for movement in plants and insect transmission but are capable of self replication in host plants. They do not appear to cause disease in plants or to alter the course of infection by the begomovirus. They may be able to reduce the severity of an infection by the begomoviruses.<ref name=Idris2011>{{cite journal |vauthors=Idris AM, Shahid MS, Briddon RW, Khan AJ, Zhu JK, Brown JK |title=An unusual alphasatellite associated with monopartite begomoviruses attenuates symptoms and reduces betasatellite accumulation |journal=J. Gen. Virol. |volume=92 |issue=Pt 3 |pages=706–17 |date=March 2011 |pmid=21084498 |doi=10.1099/vir.0.025288-0 |url=https://www.microbiologyresearch.org/docserver/fulltext/jgv/92/3/706.pdf?expires=1594264597&id=id&accname=guest&checksum=6276C22AFA8A77C5C13781CC81EF261C |format=pdf |doi-access=free }}</ref><ref name=Nawaz-Ul-Rehman2010>{{cite journal |vauthors=Nawaz-Ul-Rehman MS, Nahid N, Mansoor S, Briddon RW, Fauquet CM |title=Post-transcriptional gene silencing suppressor activity of two non-pathogenic alphasatellites associated with a begomovirus |journal=Virology |volume=405 |issue=2 |pages=300–8 |date=September 2010 |pmid=20598726 |doi=10.1016/j.virol.2010.06.024 |doi-access=free }}</ref>


Alphasatellites have also been described in association with the [[Nanoviridae]]. These tend to be slightly shorter (1100-1300 nucleotides) but to encode proteins in addition to the ''rep'' gene. Because of the multiple component genome of the ''Nanoviridae'' these were not initially recognised as distinct genomes.<ref name=Katul1995>Katul L, Maiss E, Vetten HJ (1995) Sequence analysis of a faba bean necrotic yellows virus DNA component containing a putative replicase gene. J. Gen. Virol. 76: 475–479</ref><ref name=Katul1998>Katul L, Timchenko T, Gronenborn B, Vetten HJ (1998) Ten distinct circular ssDNA components, four of which encode putative replication-associated proteins, are associated with the faba bean necrotic yellows virus genome. J Gen Virol 79: 3101–3109</ref><ref name=Sano1998>Sano Y, Wada M, Hashimoto Y, Matsumoto T, Kojima M, 1998. Sequences of ten circular ssDNA components associated with the milk vetch dwarf virus genome. J Gen Virol 79, 3111–3118</ref>
Alphasatellites have also been described in association with ''[[Nanoviridae]]''. These tend to be slightly shorter (1100–1300 nucleotides) but to encode proteins in addition to the ''rep'' gene. Because of the multiple component genome of the ''Nanoviridae'' these were not initially recognised as distinct genomes.<ref name=Katul1995>{{cite journal |vauthors=Katul L, Maiss E, Vetten HJ |title=Sequence analysis of a faba bean necrotic yellows virus DNA component containing a putative replicase gene |journal=J. Gen. Virol. |volume=76 |issue=Pt 2 |pages=475–9 |date=February 1995 |pmid=7844570 |url=https://www.microbiologyresearch.org/docserver/fulltext/jgv/76/2/JV0760020475.pdf?expires=1594264657&id=id&accname=guest&checksum=40B68894FBAF4A7E05779EBF6527A803 |doi=10.1099/0022-1317-76-2-475 |format=pdf |doi-access=free }}</ref><ref name=Katul1998>{{cite journal |vauthors=Katul L, Timchenko T, Gronenborn B, Vetten HJ |title=Ten distinct circular ssDNA components, four of which encode putative replication-associated proteins, are associated with the faba bean necrotic yellows virus genome |journal=J. Gen. Virol. |volume=79 |issue=Pt 12 |pages=3101–9 |date=December 1998 |pmid=9880028 |url=https://www.microbiologyresearch.org/docserver/fulltext/jgv/79/12/0793101a.pdf?expires=1594264733&id=id&accname=guest&checksum=0ECC45C9F103A817302A3773D4E43B83 |doi=10.1099/0022-1317-79-12-3101 |format=pdf |doi-access=free }}</ref><ref name=Sano1998>{{cite journal |vauthors=Sano Y, Wada M, Hashimoto Y, Matsumoto T, Kojima M |title=Sequences of ten circular ssDNA components associated with the milk vetch dwarf virus genome |journal=J. Gen. Virol. |volume=79 |issue=Pt 12 |pages=3111–8 |date=December 1998 |pmid=9880029 |url=https://www.microbiologyresearch.org/docserver/fulltext/jgv/79/12/0793111a.pdf?expires=1594264783&id=id&accname=guest&checksum=C77A3D9E53920B8243ADFECB4AA4A7B4 |format=pdf |doi=10.1099/0022-1317-79-12-3111 |doi-access=free }}</ref>


Alphasatellites may be the target of RNA silencing.<ref name=Amin2011>Amin I, Hussain K, Akbergenov R, Yadav JS, Qazi J, Mansoor S, Hohn T, Fauquet CM, Briddon RW (2011) Suppressors of RNA silencing encoded by the components of the cotton leaf curl begomovirus-betasatellite complex. Mol Plant Microbe Interact 24(8):973-983</ref>
Alphasatellites may be the target of RNA silencing.<ref name=Amin2011>{{cite journal |vauthors=Amin I, Hussain K, Akbergenov R |title=Suppressors of RNA silencing encoded by the components of the cotton leaf curl begomovirus-betasatellite complex |journal=Mol. Plant Microbe Interact. |volume=24 |issue=8 |pages=973–83 |date=August 2011 |pmid=21751853 |doi=10.1094/MPMI-01-11-0001 |display-authors=etal|doi-access=free }}</ref>


==Taxonomy==
==Taxonomy==
Alphasatellites are grouped together in the family ''Alphasatellitidae''. This family has three subfamilies, 18 genera, and 85 species. The following subfamilies and genera are recognized (-''satellitinae'' denotes subfamily and -''satellite'' denotes genus):<ref name="ICTV"> {{cite web |title=Virus Taxonomy: 2022 Release |url=https://ictv.global/taxonomy |website=International Committee on Taxonomy of Viruses (ICTV) |access-date=14 August 2023 |language=en |date=March 2023}} </ref>

* ''[[Geminialphasatellitinae]]''
There is no formal type member.
** ''[[Ageyesisatellite]]''

** ''[[Clecrusatellite]]''
At present alphasatellites are not organised into genera or higher taxa. A division between those associated with the Begomoviruses and those with associated with Nanoviridae seems logical at present.
** ''[[Colecusatellite]]''

** ''[[Draflysatellite]]''
It is recommended that strains with 80%+ identity be classified into a species.<ref name=Briddon2008>Briddon RW, Brown JK, Moriones E, Stanley J, Zerbini M, Zhou X, Fauquet CM (2008) Recommendations for the classification and nomenclature of the DNA-beta satellites of begomoviruses. Arch Virol 153(4):763-781</ref> Proposals for their consistent naming have also been proposed.
** ''[[Gosmusatellite]]''
** ''[[Somasatellite]]''
** ''[[Whiflysatellite]]''
* ''[[Nanoalphasatellitinae]]''
** ''[[Clostunsatellite]]''
** ''[[Fabenesatellite]]''
** ''[[Milvetsatellite]]''
** ''[[Mivedwarsatellite]]''
** ''[[Sophoyesatellite]]''
** ''[[Subclovsatellite]]''
* ''[[Petromoalphasatellitinae]]''
** ''[[Babusatellite]]''
** ''[[Cocosatellite]]''
** ''[[Coprasatellite]]''
** ''[[Kobbarisatellite]]''
** ''[[Muscarsatellite]]''


==Evolution==
==Evolution==


Given the similarities between the ''rep'' proteins of the alphasatellites and the nanoviruses, it is likely that the alphasatellites evolved from the nanoviruses.<ref name="Xie2010"/> Further work in this area is needed to clarify this.
Given the similarities between the ''rep'' proteins of the alphasatellites and the [[nanovirus]]es, it is likely that the alphasatellites evolved from the nanoviruses.<ref name="Xie2010"/>


==Uses==
==Uses==


These viruses have been used in the development of viral gene silencing studies.<ref name=Huang2011>Huang CJ, Zhang T, Li FF, Zhang XY, Zhou XP (2011) Development and application of an efficient virus-induced gene silencing system in Nicotiana tabacum using geminivirus alphasatellite. J Zhejiang Univ Sci B 12(2):83-92</ref>
These viruses have been used in the development of viral gene silencing studies.<ref name=Huang2011>{{cite journal |vauthors=Huang CJ, Zhang T, Li FF, Zhang XY, Zhou XP |title=Development and application of an efficient virus-induced gene silencing system in Nicotiana tabacum using geminivirus alphasatellite |journal=J Zhejiang Univ Sci B |volume=12 |issue=2 |pages=83–92 |date=February 2011 |pmid=21265040 |pmc=3030953 |doi=10.1631/jzus.B1000157 }}</ref>

==See also==
*[[Betasatellite]]


==References==
==References==
{{reflist|2}}
{{reflist|2}}

==External links ==

*[https://viralzone.expasy.org/8576 ViralZone Alphasatellitidae]


{{Baltimore classification}}
{{Baltimore classification}}

{{Taxonbar|from=Q52173726}}


[[Category:DNA viruses]]
[[Category:DNA viruses]]
[[Category:Satellite viruses]]

Latest revision as of 03:37, 29 November 2023

Alphasatellitidae
Virus classification Edit this classification
(unranked): Virus
Family: Alphasatellitidae

Alphasatellites are a single-stranded DNA family of satellite viruses that depend on the presence of another virus (helper viruses) to replicate their genomes. As such, they have minimal genomes with very low genomic redundancy. The genome is a single circular single strand DNA molecule.[1] The first alphasatellites were described in 1999 and were associated with cotton leaf curl disease and Ageratum yellow vein disease.[2][3] As begomoviruses are being characterised at the molecular level an increasing number of alphasatellites are being described.

These viruses were earlier known as DNA 1 components.[4]

These viruses are generally found in the Old World. A number have been isolated from the New World but their association with their host viruses is still being studied.

Genome[edit]

The genome is between 1300 and 1400 nucleotides in length and has three conserved features: a hairpin structure, a single open reading frame (ORF) and an adenine rich region.[5]

The hairpin structure has a loop that includes the nonanucleotide, TAGTATTAC, which is common to nanoviruses and differs from the TAATATTAC sequence of geminiviruses by one nucleotide. In both geminiviruses and nanoviruses this sequence contains the origin of replication (ori) and is nicked by the rolling circle replication initiator protein to initiate viral DNA replication. On the basis of the hairpin structures alphasatellites can be divided into 5 clades.[6]

The open reading frame encodes a rolling circle replication initiator protein (Rep) similar to that found in the nanoviruses. The encoded protein is 32–37 kilodalton in molecular weight with ~320 amino acids. It is highly conserved with 86.3–100.0% amino acid sequence identity between isolates.[citation needed]

The adenine rich region is immediately downstream of the rep gene and is approximately 153–169 nucleotides in length with an adenine content of between 52.3–58.4%. Phylogenectic analysis of this region shows that they can be divided into three clades which correspond to those found on phylogenetic analysis of the entire genome.[6] This portion of the genome appears to be redundant.[7]

A putative second ORF in the genome of an alphasatellite virus has been described.[8] The significance of this finding (if any) is not known.

Recombination occurs between alphasatellites.[9]

Virology[edit]

There are no distinctive virions because the viral genomes are encapsidated within the coat protein of the helper virus.[citation needed]

Alphasatellites associated with the begomoviruses require a begomovirus for movement in plants and insect transmission but are capable of self replication in host plants. They do not appear to cause disease in plants or to alter the course of infection by the begomovirus. They may be able to reduce the severity of an infection by the begomoviruses.[10][11]

Alphasatellites have also been described in association with Nanoviridae. These tend to be slightly shorter (1100–1300 nucleotides) but to encode proteins in addition to the rep gene. Because of the multiple component genome of the Nanoviridae these were not initially recognised as distinct genomes.[12][13][14]

Alphasatellites may be the target of RNA silencing.[15]

Taxonomy[edit]

Alphasatellites are grouped together in the family Alphasatellitidae. This family has three subfamilies, 18 genera, and 85 species. The following subfamilies and genera are recognized (-satellitinae denotes subfamily and -satellite denotes genus):[16]

Evolution[edit]

Given the similarities between the rep proteins of the alphasatellites and the nanoviruses, it is likely that the alphasatellites evolved from the nanoviruses.[6]

Uses[edit]

These viruses have been used in the development of viral gene silencing studies.[17]

References[edit]

  1. ^ Silva, Jorge Miguel; Pratas, Diogo; Caetano, Tânia; Matos, Sérgio (2022-08-11). "The complexity landscape of viral genomes". GigaScience. 11: giac079. doi:10.1093/gigascience/giac079. ISSN 2047-217X. PMC 9366995. PMID 35950839.
  2. ^ Saunders K, Stanley J (November 1999). "A nanovirus-like DNA component associated with yellow vein disease of Ageratum conyzoides: evidence for interfamilial recombination between plant DNA viruses". Virology. 264 (1): 142–52. doi:10.1006/viro.1999.9948. PMID 10544139.
  3. ^ Mansoor S, Khan SH, Bashir A, et al. (June 1999). "Identification of a novel circular single-stranded DNA associated with cotton leaf curl disease in Pakistan". Virology. 259 (1): 190–9. doi:10.1006/viro.1999.9766. PMID 10364503.
  4. ^ Stanley J (February 2004). "Subviral DNAs associated with geminivirus disease complexes". Vet. Microbiol. 98 (2): 121–9. doi:10.1016/j.vetmic.2003.10.005. PMID 14741124.
  5. ^ Briddon RW, Bull SE, Amin I, et al. (July 2004). "Diversity of DNA 1: a satellite-like molecule associated with monopartite begomovirus-DNA beta complexes". Virology. 324 (2): 462–74. doi:10.1016/j.virol.2004.03.041. PMID 15207631.
  6. ^ a b c Xie Y, Wu P, Liu P, Gong H, Zhou X (2010). "Characterization of alphasatellites associated with monopartite begomovirus/betasatellite complexes in Yunnan, China". Virol. J. 7: 178. doi:10.1186/1743-422X-7-178. PMC 2922188. PMID 20678232.
  7. ^ Shahid MS, Ali L, Andleeb S (2009). "The function of the a-rich region of the alphasatellite associated with the cotton leaf curl disease in Pakistan" (PDF). EurAsia J BioSci. 3: 152–6. Archived from the original (PDF) on 2014-03-08. Retrieved 2014-03-08.
  8. ^ Romay G, Chirinos D, Geraud-Pouey F, Desbiez C (November 2010). "Association of an atypical alphasatellite with a bipartite New World begomovirus". Arch. Virol. 155 (11): 1843–7. doi:10.1007/s00705-010-0760-7. PMID 20665058. S2CID 20039085.
  9. ^ Kumar J, Kumar A, Roy JK, Tuli R, Khan JA (August 2010). "Identification and molecular characterization of begomovirus and associated satellite DNA molecules infecting Cyamopsis tetragonoloba". Virus Genes. 41 (1): 118–25. doi:10.1007/s11262-010-0482-7. PMID 20405195. S2CID 6790138.
  10. ^ Idris AM, Shahid MS, Briddon RW, Khan AJ, Zhu JK, Brown JK (March 2011). "An unusual alphasatellite associated with monopartite begomoviruses attenuates symptoms and reduces betasatellite accumulation" (pdf). J. Gen. Virol. 92 (Pt 3): 706–17. doi:10.1099/vir.0.025288-0. PMID 21084498.
  11. ^ Nawaz-Ul-Rehman MS, Nahid N, Mansoor S, Briddon RW, Fauquet CM (September 2010). "Post-transcriptional gene silencing suppressor activity of two non-pathogenic alphasatellites associated with a begomovirus". Virology. 405 (2): 300–8. doi:10.1016/j.virol.2010.06.024. PMID 20598726.
  12. ^ Katul L, Maiss E, Vetten HJ (February 1995). "Sequence analysis of a faba bean necrotic yellows virus DNA component containing a putative replicase gene" (pdf). J. Gen. Virol. 76 (Pt 2): 475–9. doi:10.1099/0022-1317-76-2-475. PMID 7844570.
  13. ^ Katul L, Timchenko T, Gronenborn B, Vetten HJ (December 1998). "Ten distinct circular ssDNA components, four of which encode putative replication-associated proteins, are associated with the faba bean necrotic yellows virus genome" (pdf). J. Gen. Virol. 79 (Pt 12): 3101–9. doi:10.1099/0022-1317-79-12-3101. PMID 9880028.
  14. ^ Sano Y, Wada M, Hashimoto Y, Matsumoto T, Kojima M (December 1998). "Sequences of ten circular ssDNA components associated with the milk vetch dwarf virus genome" (pdf). J. Gen. Virol. 79 (Pt 12): 3111–8. doi:10.1099/0022-1317-79-12-3111. PMID 9880029.
  15. ^ Amin I, Hussain K, Akbergenov R, et al. (August 2011). "Suppressors of RNA silencing encoded by the components of the cotton leaf curl begomovirus-betasatellite complex". Mol. Plant Microbe Interact. 24 (8): 973–83. doi:10.1094/MPMI-01-11-0001. PMID 21751853.
  16. ^ "Virus Taxonomy: 2022 Release". International Committee on Taxonomy of Viruses (ICTV). March 2023. Retrieved 14 August 2023.
  17. ^ Huang CJ, Zhang T, Li FF, Zhang XY, Zhou XP (February 2011). "Development and application of an efficient virus-induced gene silencing system in Nicotiana tabacum using geminivirus alphasatellite". J Zhejiang Univ Sci B. 12 (2): 83–92. doi:10.1631/jzus.B1000157. PMC 3030953. PMID 21265040.

External links[edit]

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