Plant virus RNA replication

Plant RNA (ribonucleic acid) viruses are obligate intracellular parasites with single-stranded (ss) or double-stranded RNA genome(s) generally encapsidated but rarely enveloped. For viruses with ssRNA genomes, the polarity of the infectious RNA (positive or negative) and the presence of one or more genomic RNA segments are the features that mostly determine the molecular mechanisms governing the replication process. RNA viruses cannot penetrate plant cell walls unaided and must enter the cellular cytoplasm through mechanically induced wounds or assisted by a biological vector. After desencapsidation, their genome remains in the cytoplasm where it is translated, replicated and encapsidated in a coupled manner. Replication occurs in large viral replication complexes (VRCs), tethered to modified membranes of cellular organelles and composed by the viral RNA templates and by viral and host proteins. Cis-acting elements located in viral RNA templates regulate the recognition by the virus-encoded RNA-dependent RNA polymerase and possibly contribute to VRC assembly and/or activation.

Work in the authors’ laboratories is supported by grants BFU2012-36095 BIO2013-49053-R and Plant KBBE PCIN-2013-056 from the Ministerio de Economía y Competitividad (MINECO, Spain) and from the European Union’s Horizon 2020 research and innovation programme under the Marie Sklodowska-Curie grant agreement No 655841.

Peer Reviewed