Viroids: Non-Coding Circular RNAs Able to Autonomously Replicate and Infect Higher Plants

[EN] Viroids are a unique type of infectious agent, exclusively composed of a relatively small (246¿430 nt), highly base-paired, circular, non-coding RNA. Despite the small size and non-coding nature, the more-than-thirty currently known viroid species infectious of higher plants are able to autonom...

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Detalles Bibliográficos
Autores: Ortola, Beltrán, Daròs, José-Antonio|||0000-0002-6535-2889
Tipo de recurso: artículo
Fecha de publicación:2023
País:España
Institución:Universitat Politècnica de València (UPV)
Repositorio:RiuNet. Repositorio Institucional de la Universitat Politécnica de Valéncia
Idioma:inglés
OAI Identifier:oai:riunet.upv.es:10251/205644
Acceso en línea:https://riunet.upv.es/handle/10251/205644
Access Level:acceso abierto
Palabra clave:Circular RNA
Non-coding RNA
Infectious agent
Host plant
Rolling-circle replication
Hammerhead ribozyme
RNA silencing
Descripción
Sumario:[EN] Viroids are a unique type of infectious agent, exclusively composed of a relatively small (246¿430 nt), highly base-paired, circular, non-coding RNA. Despite the small size and non-coding nature, the more-than-thirty currently known viroid species infectious of higher plants are able to autonomously replicate and move systemically through the host, thereby inducing disease in some plants. After recalling viroid discovery back in the late 60s and early 70s of last century and discussing current hypotheses about their evolutionary origin, this article reviews our current knowledge about these peculiar infectious agents. We describe the highly base-paired viroid molecules that fold in rod-like or branched structures and viroid taxonomic classification in two families, Pospiviroidae and Avsunviroidae, likely gathering nuclear and chloroplastic viroids, respectively. We review current knowledge about viroid replication through RNA-to-RNA rolling-circle mechanisms in which host factors, notably RNA transporters, RNA polymerases, RNases, and RNA ligases, are involved. Systemic movement through the infected plant, plant-to-plant transmission and host range are also discussed. Finally, we focus on the mechanisms of viroid pathogenesis, in which RNA silencing has acquired remarkable importance, and also for the initiation of potential biotechnological applications of viroid molecules.