title: Pear blister canker viroid is a member of the apple scar skin subgroup (apscaviroids) and also has sequence homology with viroids from other subgroups.
abstract: The sequence of pear blister canker viroid (PBCVd), the putative causal agent of pear blister canker (PBC) disease, has been determined. PBCVd consists of a single-stranded circular RNA of 315 nucleotide residues which assumes a branched conformation when it is folded in the model of lowest free energy. PBCVd has highest sequence similarity with grapevine 1B viroid (52.4%), but also contains sequences related to regions present in viroids that belong to different subgroups, suggesting that PBCVd could have developed from RNA recombination between viroids replicating in a common host plant. PBCVd contains almost the entire central sequence which is conserved in the members of the apple scar skin subgroup (apscaviroids) as well as a conserved sequence located in the left-terminal region of apscaviroids and pospiviroids (whose type member is potato spindle tuber viroid). A consensus phylogenetic tree has been obtained in which PBCVd and other viroids previously classified as apscaviroids appear closely related, allowing consideration of PBCVd as a new member of this subgroup.
authors.affiliation: Unidad de Biología Molecular y Celular de Plantas, Consejo Superior de Investigaciones Cientificas, Valencia, Spain.
authors.forename: C
authors.initials: C
authors.lastname: Hernández
authors.forename: S F
authors.initials: SF
authors.lastname: Elena
authors.forename: A
authors.initials: A
authors.lastname: Moya
authors.forename: R
authors.initials: R
authors.lastname: Flores
mesh_terms: D001483:Base Sequence; D016384:Consensus Sequence; D005638:Fruit / Q000382:microbiology*; D016678:Genome; D008969:Molecular Sequence Data; D009690:Nucleic Acid Conformation; D010802:Phylogeny; D010935:Plant Diseases / Q000382:microbiology*; D012313:RNA / Q000235:genetics; D012689:Sequence Homology, Nucleic Acid; D014197:Trees / Q000382:microbiology*; D014772:Viroids / Q000145:classification* / Q000235:genetics
chemical_list: D012313:RNA