Dahlia Latent Viroid

Abstract Dahlia latent viroid (DLVd) displays features characteristic of members of the family Pospiviroidae ; i.e., a predicted rod-like conformation with a central conserved region and a terminal conserved region. Allocation to a genus is more complicated since the central conserved region is identical to that of hop stunt viroid (HSVd), genus Hostuviroid , whereas the terminal conserved region is typical of members of the genus Pospiviroid . Phylogenetic analysis does not help either because DLVd is most closely related to two species of each genus; i.e., HSVd and pepper chat fruit viroid (genus Pospiviroid ). DLVd has been allocated to the genus Hostuviroid because of a common central conserved region with the type species of this genus. Dahlia is the only known host of the viroid. Infected plants are symptomless. Consequently, the economic impact is low.