The question of Citrus viroid IV as a cocadviroid

Arch Virol. 2005 Jun;150(6):1059-67. doi: 10.1007/s00705-005-0499-8. Epub 2005 Apr 13.

Abstract

It has been suggested that Citrus viroid IV (CVd-IV) be classified as a species within the genus Cocadviroid. This relationship was based on the presence of a terminal conserved hairpin (TCH) and absence of a terminal conserved region (TCR) as specific structural motifs in common with isolates of Coconut cadang-cadang viroid (CCCVd) as well as phylogenetic relationships with members of the genus Cocadviroid. Evidence is presented for a "vestigial" TCR in CVd-IV as well as the introduction of the terminal repeat region (TRR) motif and an alternative sequence analysis that suggests a closer phylogenetic relationship of CVd-IV to isolates of Citrus exocortis viroid (CEVd), a species within the genus Pospiviroid than to CCCVd. This position is further supported by the striking similarity of biological properties between CVd-IV and CEVd with the suggestion offered that biological evidence be considered for specific adjustments to any overall classification scheme for viroids.

Publication types

  • Review

MeSH terms

  • Base Sequence
  • Citrus / virology*
  • Molecular Sequence Data
  • Phylogeny
  • Plant Diseases / virology
  • Plant Viruses / classification
  • Plant Viruses / genetics
  • Viroids / classification*
  • Viroids / genetics