A viroid was isolated from Iresine herbstii plants using the bidirectional PAGE method for analysis of small circular RNA molecules. The viroid was transmitted to viroid-free Iresine herbstii plants of the cultivar ‘Aureoreticulata’ by mechanical inoculation. Infected plants did not develop any symptoms. The new viroid species has been named Iresine viroid (IrVd). It is a member of the potato spindle tuber viroid group and consists of 370 nucleotides, 227 G+C, 143 A+U (GC content, 61.4%). The most stable rod-like secondary structure of this viroid has 86 G:C, 34 A:U and 12 G:U base pairs with a minimum free energy of -153.4 kcal/mol (-641.2 kJ/mol). The sequence and the position of the terminal conserved region (TCR) within the rod-like secondary structure of IrVd differ from the other known TCRs. The structure of the left terminal domain of IrVd may reflect the result of an intramolecular RNA recombination event.
DarosJ. A.,
FloresR. H.1995; Characterization of multiple circular RNAs derived from a plant viroid-like RNA by sequence deletions and duplications. RNA 1:734–744
DienerT. O.1991; The frontier of life: the viroid and viroid-like satellites RNAs. italic>In Viroids and Satellites: Molecular Parasites at the Frontier of Life pp 1–20 Edited by
MaramoroschK.
Boca Raton: CRC Press;
HammondR.,
SmithD. R.,
DienerT. O.1989; Nucleotide sequence and proposed secondary structure of Columnea latent viroid: a natural mosaic of viroid sequences. Nucleic Acids Research 23:10083–10094
KeeseP.,
SymonsR. H.1985; Domains in viroids: evidence of intermolecular rearrangements and their contribution to viroid evolution. Proceedings of the National Academy of Sciences, USA 82:4582–4586
SangerF.,
NicklenS.,
CoulsonA. R.1977; DNA sequencing with chain-terminating inhibitors. Proceedings of the National Academy of Sciences, USA 74:5463–5467
SängerH. L.,
KlotzG.,
RiesnerD.,
GrossH. J.,
KleinschmidtA. K.1976; Viroids are single-stranded covalently closed circular RNA molecules existing as highly base-paired rod-like structures. Proceedings of the National Academy of Sciences, USA 73:3852–3856
SchumacherJ.,
RandlesJ. W.,
RiesnerD.1983; A two-dimensional electrophoresis technique for the detection of circular viroids and virusoids. Analytical Biochemistry 135:288–295
SemancikJ. S.,
SzychowskiJ. A.,
RakowskiA. G.,
SymonsR. H.1993; Isolates of citrus exocortis viroid recovered by host and tissue selection. Journal of General Virology 74:2427–2436
SinghR. P.,
LakshmanD. K.,
BoucherA.,
TavantzisS. M.1992; A viroid from Nematanthus wettsteinii plants closely related to the Columnea latent viroid. Journal of General Virology 73:2769–2774
SpiekerR. L.1991; A new class of viroids in Coleus blumei: sequencing, cloning, structure/function-analysis by site-directed mutagenesis and expression in Nicotiana tabacum
. Karlsruhe Contributions to Plant Physiology 22:1–226
SpiekerR. L.,
HaasB.,
CharngY. C.,
FreimiillerK.,
SängerH. L.1990; Primary and secondary structure of a new viroid ‘species’ (CbVd 1) present in the Coleus blumei cultivar ‘Bienvenue’
. Nucleic Acids Research 18:3998
SpiekerR. L.,
MarinkovicS.,
SängerH. L.1996; A viroid from Solanum pseudocapsicum closely related to the tomato apical stunt viroid. Archives of Virology (in press)
WasseneggerM.,
HeimesS.,
SangerH. L.1994; An infectious viroid RNA replicon evolved from an in vitro-generated non-infectious viroid deletion mutant via a complementary deletion in vivo
. EMBO Journal 13:6172–6177