imported>Lcovelli at 12:58, 15 March 2010

2010-03-15T12:58:37Z

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{{Element
|genbank=[http://www.ncbi.nlm.nih.gov/entrez/viewer.fcgi?db=nucleotide&val=347868 347868]
|type=
|genus= Badnavirus
|subfamily= Class 2
|family= Caulimoviridae
|group= LTR retroelements
|description=''Cacao swollen shoot virus'' (CSSV) is the causal agent of the "Cocoa swollen shoot disease", one of the most devastating scourges of cacao (''Theobroma cacao'') that causes serious crop losses in many cacao growing areas of West Africa ([[Literature:100658|Posnette 1947]]; [[Literature:100659|Partiot et al. 1978]]). Mild and severe isolates have been found in CSSV-endemic regions ([[Literature:100660|Castel ''et al.'' 1980]]; [[Literature:100661|Dufour 1988]]) and to date six of them have been completely characterized and sequenced ([[Literature:100662|Hagen ''et al.'' 1993]]; [[Literature:100663|Muller and Sackey 2005]]). The most virulent isolate "CSSV-Agou1" from Togo ([[Literature:100662|Hagen ''et al.'' 1993]]) is the reference sequence in our analyses. CSSV is a member of ''Caulimoviridae'' family, genus ''Badnavirus'' (''International Committee on the Taxonomy of Viruses'' -ICTV- [[Literature:100589|Fauquet ''et al''. 2005]]), and according to [[Literature:100596|Llorens ''et al''. 2009]] is located within Class 2 of the [[Caulimoviridae|''Caulimoviridae'']] family.

CSSV is a small non-enveloped bacilliform virus which particles are approximately 28x112-130 nm ([[Literature:100664|Brunt ''et al'' 1964]]) and contain a circular double-stranded DNA genome interrupted by site-specific discontinuities ([[Literature:100665|Lot ''et al.'' 1991]]). DsDNA molecule, 7161 bp long, encodes for five open reading frames (ORFI, II, III, X, Y) located on the plus strand of the genome, some of which contain the highly conserved Badnavirus protein domains ([[Literature:100662|Hagen ''et al.'' 1993]]; [[Literature:100663|Muller and Sackey 2005]]). ORFI encodes a putative 16.8 kDa protein showing sequence similarity to the ''Caulimoviridae'' virion associated proteins (VAPs) encoded by the corresponding ORFs I. The ORFII product of 14.4 kDa has been demonstrated to possess a potentially nucleic acid-binding property ([[Literature:100640|Jacquot ''et al.'' 1996]]). ORF III of about 211 kDa contains consensus sequences for a cell-to-cell movement protein (MOV), an RNA binding domain of the coat protein (COAT), an aspartyl proteinase (PR), a reverse transcriptase (RT) and a ribonuclease H (RH) ([[Literature:100662|Hagen ''et al.'' 1993]]; [[Literature:100663|Muller and Sackey 2005]]). In particular the COAT (''gag'')-like region includes the two cysteine-rich domains "C-X-C-X2-C-X4-H-X4-C" and "C-X2-C-X11-C-X2-C-X4-C-X2-C" only observed in Badna- and Tungroviruses and similar to those identified in the nucleocapsid domains of LTR retroelements ([[Literature:100605|Hull 1996]]; [[Literature:8054|Bouhida ''et al.'' 1993]]; [[Literature:100596|Llorens ''et al''. 2009]]).
ORFs X and Y, corresponding to proteins of 13.2 and 14.2 kDa respectively, are located within ORF III ([[Literature:100662|Hagen ''et al.'' 1993]]). ORF Y overlaps the end of ORF III as observed for ''Citrus yellow mosaic virus'' (CYMV)-ORF VI whose products show some sequence homologies ([[Literature:100651|Huang and Hurtung 2001]]). No described protein similarities have been found to both ORF X and Y products ([[Literature:100662|Hagen ''et al.'' 1993]]).

The typical "Cacao swollen shoot disease" symptomatology consists in shoot, stem and root swellings, leaf mosaic and chlorosis, red vein banding, defoliation and round pods, and die within three to four years following infection in susceptible cacao cultivars ([[Literature:100659|Partiot ''et al.'' 1978]]; [[Literature:100660|Castel ''et al.'' 1980]]). CSSV is naturally transmitted to cacao plants by several species of mealybug (''Pseudococcidae''), including ''Planococcus citri'', in a semi-persistent manner ([[Literature:100661|Dufour 1988]]), but it can also been transmitted by plant-agroinoculation ([[Literature:100666|Jacquot ''et al.'' 1999]]) and seed-biolistic inoculation (particles bombardment, [[Literature:100667|Hagen ''et al.'' 1994]]). Virus has been detected in both pollen and seed and considering that currently cocoa is propagated largely by seeds, exist considerable evidence that viruses have been introduced into many geographical regions by infected seeds and through increasing international germplasm exchanges ([[Literature:96093|Quainoo ''et al.'' 2008]]).
|structure=CSSV.png
|host=Theobroma cacao
|hostpic=Theobroma_cacao.jpg
|literature=
|picowner= [http://www.biolib.cz/en/taxonimage/id44487/ Courtesy of the Biological library (BioLib), Jan Ševcík author]
}}
[[Category:Element]]

Element:CSSV - Revision history

imported>Lcovelli at 12:58, 15 March 2010