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Type Species |
Coleus blumei viroid 1 |
(CbVd-1) |
A circular ssRNA between 248 and 250-251 bases depending on isolates and sequence variants. The most stable secondary structure is a rod-like or quasi-rod-like conformation with five domains and a central conserved region (CCR) (Fig. 2). Replication most probably occurs through an asymmetric rolling-circle model by analogy with PSTVd (Fig. 3). Known hosts are confined to Coleus genus. Identified in Brazil, Canada and Germany.
Fusion of the right-hand part and the CCR of Coleus blumei viroid 1 (CbVd-1) with the left-hand part of Coleus blumei viroid 3 (CbVd-3) leads to the recombinant Coleus blumei viroid 2 (CbVd-2) which, therefore, is composed of two essentially unchanged parental sequences whose joining points are characterized by a sharply defined boundary.
List of Species Demarcation Criteria in the Genus
An arbitrary level of less than 90% sequence similarity and distinct biological properties, particularly host range, currently separates species within genera.
Official viroid species names are in italics. Tentative names, alternative names ( ), or strains are not italicized. Viroid names, CMI/AAB description numbers ( ), genomic accession numbers of typical sequence variants [ ], sizes {b}, and assigned abbreviations ( ) are:
|
Coleus blumei viroid 1 |
[X52960] |
{248, 250-251} |
(CbVd-1) |
|
Coleus blumei viroid 2 |
[X95365] |
{301-302} |
(CbVd-2) |
|
Coleus blumei viroid 3 |
[X95364] |
{361-362, 364} |
(CbVd-3) |
Tentative Species in the Genus
None reported.
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