title: Viroid RNA turnover: characterization of the subgenomic RNAs of potato spindle tuber viroid accumulating in infected tissues provides insights into decay pathways operating in vivo.
abstract: While biogenesis of viroid RNAs is well-known, how they decay is restricted to data involving host RNA silencing. Here we report an alternative degradation pathway operating on potato spindle tuber viroid (PSTVd), the type species of nuclear-replicating viroids (family Pospiviroidae). Northern-blot hybridizations with full- and partial-length probes revealed a set of PSTVd (+) subgenomic (sg)RNAs in early-infected eggplant, some partially overlapping and reaching levels comparable to those of the genomic circular and linear forms. Part of the PSTVd (+) sgRNAs were also observed in Nicotiana benthamiana (specifically in the nuclei) and tomato, wherein they have been overlooked due to their low accumulation. Primer extensions of representative (+) sgRNAs failed to detect a common 5' terminus, excluding that they could result from aborted transcription initiated at one specific site. Supporting this view, 5'- and 3'-RACE indicated that the (+) sgRNAs have 5'-OH and 3'-P termini most likely generated by RNase-mediated endonucleolytic cleavage of longer precursors. These approaches also unveiled PSTVd (-) sgRNAs with features similar to their (+) counterparts. Our results provide a mechanistic insight on how viroid decay may proceed in vivo during replication, and suggest that synthesis and decay of PSTVd strands might be coupled as in mRNA.
authors: Instituto de Biología Molecular y Celular de Plantas (IBMCP), Universidad Politécnica de Valencia-Consejo Superior de Investigaciones Científicas, Valencia, Spain.
authors: Sofia
authors: S
authors: Minoia
authors: Istituto per la Protezione Sostenibile delle Piante, UOS Bari, Consiglio Nazionale delle Ricerche, Bari, Italy.
authors: Beatriz
authors: B
authors: Navarro
authors: Instituto de Biología Molecular y Celular de Plantas (IBMCP), Universidad Politécnica de Valencia-Consejo Superior de Investigaciones Científicas, Valencia, Spain.
authors: Sonia
authors: S
authors: Delgado
authors: Istituto per la Protezione Sostenibile delle Piante, UOS Bari, Consiglio Nazionale delle Ricerche, Bari, Italy rflores@ibmcp.upv.es.
authors: Francesco
authors: F
authors: Di Serio
authors: Instituto de Biología Molecular y Celular de Plantas (IBMCP), Universidad Politécnica de Valencia-Consejo Superior de Investigaciones Científicas, Valencia, Spain rflores@ibmcp.upv.es.
authors: Ricardo
authors: R
authors: Flores
mesh_terms: D002467:Cell Nucleus / Q000821:virology; D016679:Genome, Viral; D010935:Plant Diseases / Q000821:virology*; D020871:RNA Stability; D012367:RNA, Viral / Q000737:chemistry / Q000378:metabolism*; D032323:Solanum melongena / Q000821:virology; D014772:Viroids / Q000235:genetics* / Q000502:physiology; D014779:Virus Replication
chemical_list: D012367:RNA, Viral