imported>Lcovelli at 13:34, 15 March 2010

2010-03-15T13:34:33Z

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{{Element
|genbank=[http://www.ncbi.nlm.nih.gov/entrez/viewer.fcgi?db=nucleotide&val=15029533 15029533]
|type=
|genus= Badnavirus
|subfamily= Class 2
|family= Caulimoviridae
|group= LTR retroelements
|description=''Sugarcane bacilliform virus'' (SCBV) is a pathogen of sugarcane (''Saccharum Spp''. and ''Saccharum L''. interspecific hybrids) which was first observed in Cuba in 1985 ([[Literature:100670|Rodriguez-Lema ''et al''. 1985]]) and first purified from a sugarcane variety growing in Morocco ([[Literature:100688|Lockhart and Autrey 1988]]). It is a plant pararetrovirus of ''Badnavirus'' genus, ''Caulimoviridae'' family (''International Committee on the Taxonomy of Viruses'' -ICTV- [[Literature:100589|Fauquet ''et al''. 2005]]). To date have been completely sequenced two isolate, one from Morocco ([http://www.ncbi.nlm.nih.gov/nuccore/294836 ScBMorV], [[Literature:8054|Bouhida ''et al.'' 1993]]) and one from Australia ([http://www.ncbi.nlm.nih.gov/nuccore/AJ277091 ScBIMV], [[Literature:100671|Geijskes ''et al.'' 2002]]).
The SCBV sequence selected for our study is that isolated from the Australian "Ireng Maleng” variety (ScBIMV) and according to [[Literature:100596|Llorens ''et al''. 2009]]it is located within Class 2 of the [[Caulimoviridae|''Caulimoviridae'']] family.

ScBIMV has non-enveloped bacilliform-shaped particles with a size of approximately 30 nm x 130 nm, although virions up to 500 nm in length have been reported ([[Literature:100688|Lockhart and Autrey 1988]]; [[Literature:100672|Geijskes ''et al.'' 2004]]), containing a circular dsDNA of about 7.6 Kb in size (7687 bp long) ([[Literature:100671|Geijskes ''et al.'' 2002]]). Analysis of the genome sequence reveals that the plus strand contains three Open reading frames (ORFs I, II, III) which size, number and arrangement are similar to those of the badnaviruses ([[Literature:100671|Geijskes ''et al.'' 2002]]). The predicted ORF I product of 21.8 kDa shows sequence similarity to the ''Caulimoviridae'' virion associated proteins (VAPs) encoded by the corresponding ORFs I. The function of ORFII product (16.4 kDa) has not yet been demonstrated, even if a DNA-binding property has been hypothesized for the ORF II products of some badnaviruses ([[Literature:86820|Borah ''et al.'' 2009]]; [[Literature:100640|Jacquot ''et al.'' 1996]]). The polyprotein encoded by ORF III contains the typical ''Badnavirus'' cell-to-cell movement protein (MOV), viral coat protein (COAT), aspartic protease (PR), reverse transcriptase (RT) and RNase H (RH) domains ([[Literature:100671|Geijskes ''et al.'' 2002]]). At the C-terminus of the COAT (gag)-like domain is present the large cysteine-rich region characteristic of Badna- and Tungroviruses ([[Literature:100596|Llorens ''et al''. 2009]]; [[Literature:100605|Hull 1996]]; [[Literature:8054|Bouhida ''et al.'' 1993]]).

SCBV is present in the majority sugarcane-growing countries ([[Literature:100674|Autrey ''et al.'' 1995]]; [[Literature:100673|Comstock and Lockhart 1990]]) causing yield reductions in some varieties. The symptoms of infection are variable ([[Literature:100671|Geijskes ''et al.'' 2002]]) and severely infected varieties display chlorotic leaf speckle, stunted growth, reduction in internodal elongation and premature death, while other varieties remain symptomless ([[Literature:100675|Viswanathan ''et al.'' 1996]]; [[Literature:100673|Comstock and Lockhart 1990]]; [[Literature:100688|Lockhart and Autrey 1988]]). The virus is transmitted by natural vectors -as the pink (''Saccharicoccus sacchari'') and grey (''Dysmicoccus boninsis'') sugarcane mealybugs- as well as mechanically to sugarcane plants and by Agroinoculation to both rice and banana plants ([[Literature:100688|Lockhart and Autrey 1988]], [[Literature:100689|1991]]; [[Literature:100674|Autrey ''et al.'' 1995]]; [[Literature:8054|Bouhida ''et al.'' 1993]]).
[[Literature:100672|Geijskes ''et al.'']] (2004) investigated the possible integration of SCBV sequences into the sugarcane genome. Their results provided evidence indicating that SCBV did not integrate into the genomes of the sugarcane cultivars tested and that the high molecular weight DNA observed were SCBV concatamers comprising up to four genome copies (derived by an open circular concatamer formation). However, considering that SCBV is hypervariable, the authors do not discard the possibility that a distant strain of SCBV is not integrated into the sugarcane genomes tested or into other sugarcane genomes.
|structure=ScBIMV.png
|host=Saccharum L.
|hostpic=Saccharum_L.jpg
|literature=
|picowner=[http://botany.si.edu/index.htm Courtesy of Robert Soreng, Department of Botany, Smithsonian National Museum of Natural History,Washington D.C.]
}}
[[Category:Element]]

Element:ScBIMV - Revision history

imported>Lcovelli at 13:34, 15 March 2010