imported>Lcovelli at 11:59, 15 March 2010

2010-03-15T11:59:09Z

New page

{{Element
|genbank=[http://www.ncbi.nlm.nih.gov/entrez/viewer.fcgi?db=nucleotide&val=27802648 27802648]
|type=
|genus= Badnavirus
|subfamily= Class 2
|family= Caulimoviridae
|group= LTR retroelements
|description=''Kalanchoë top-spotting virus'' (KTSV) is a plant pararetrovirus isolated from the flowering pot plants ''Kalanchoë blossfeldiana'' ([[Literature:100646|Yang ''et al.'' 2005]]). It is a member of the genus ''Badnavirus'' of ''Caulimoviridae'' family (''International Committee on the Taxonomy of Viruses'' -ICTV- [[Literature:100589|Fauquet ''et al''. 2005]]) and according to [[Literature:100596|Llorens ''et al''. 2009]] it is located within Class 2 of the [[Caulimoviridae|''Caulimoviridae'']] family.

KTSV bacilliform-shaped particles, of approximately 20-25nm x 40-100nm in size ([[Literature:100647|Hearon and Locke 1984]]), contain a circular double-stranded DNA genome 7591 bp long encoding for three Open reading frames (ORFs I, II, III) which potentially encoded proteins have molecular masses similar to those of the corresponding proteins of other badnaviruses ([[Literature:100646|Yang ''et al.'' 2005]]). The putative ORF I protein shows sequence similarity to the ''Caulimoviridae'' virion associated proteins (VAPs). ORF II potentially encodes a protein of 13.8 kDa which function is still unknown. As reported for other badnaviruses, the ORF III product is a polyprotein with the typical cell-to-cell movement protein (MOV), viral gag-like coat (COAT), aspartic protease (PR), reverse transcriptase (RT) and RNase H (RH) domains. The COAT region includes a large region (only observed in Badna- and Tungroviruses) that is rich in zinc finger (CCHC) arrays similar to those found in the LTR retroelement gag-nucleocapsids ([[Literature:100605|Hull 1996]]; [[Literature:8054|Bouhida ''et al.'' 1993]]; [[Literature:100596|Llorens ''et al''. 2009]]).

KTSV is the causal agent of the "top-spotting disease" of kalanchoë ([[Literature:100647|Hearon and Locke 1984]]; [[Literature:100648|Lockhart and Ferji 1988]]). The disease occurs in many commercially traded cultivars of Europe and North America and is characterized by the appearance of numerous chlorotic spots and ring spots on emerging leaves during periods of vigorous vegetative growth. This pararetrovirus can be transmitted by the citrus mealybug vector ''Planococcus citri'', by mechanical inoculation (less) as well as by graft, seed, and pollen ([[Literature:100647|Hearon and Locke 1984]]). However the natural spread of the top-spotting disease in commercially grown kalanchoë remains primarily by vegetative propagation of infected plants ([[Literature:100646|Yang ''et al.'' 2005]]). KTSV occurs frequently in mixed infections with the ''Carlavirus'' sp., ''Kalanchoë latent virus'' (KLV, [[Literature:100649|Hearon 1982]]) and the ''Potyvirus'' sp., ''Kalanchoë mosaic virus'' (KMV, [[Literature:100650|Husted ''et al.'' 1994]]), ([[Literature:100646|Yang ''et al.'' 2005]]).

As found in other badna- and caulimoviruses genome ([[Literature:29391|Harper ''et al.'' 2002]]), the presence of KTSV Endogenous pararetrovirus (EPRV)-like sequences has been also described indicating that they may represent integrated pararetroviral elements in the kalanchoë genome ([[Literature:100646|Yang ''et al.'' 2005]]).
|structure=KTSV.png
|host=Kalanchoe blossfeldiana
|hostpic=Kalanchoe.jpg
|literature=
|picowner=[http://www.biotechvana.com Image, Laura Covelli, <br>Copyright, GyDB, Biotech Vana]
}}
[[Category:Element]]

Element:KTSV - Revision history

imported>Lcovelli at 11:59, 15 March 2010