Satellite RNA Is Essential for Encapsidation of Groundnut Rosette Umbravirus RNA by Groundnut Rosette Assistor Luteovirus Coat Protein

• Published in: Virology (New York, N.Y.) N.Y.), 1999-02, Vol.254 (1), p.105-114
• Main Authors: Robinson, D.J., Ryabov, E.V., Raj, S.K., Roberts, I.M., Taliansky, M.E.
• Format: Article
• Language: English
• Subjects: Animals; Aphids; Capsid - metabolism; Groundnut rosette assistor virus; Groundnut rosette virus; Luteovirus; Luteovirus - metabolism; Mutagenesis; Nicotiana; Open Reading Frames; Plant Viruses - genetics; Plant Viruses - physiology; Plants, Genetically Modified; Plants, Toxic; RNA Viruses - genetics; RNA Viruses - physiology; RNA, Satellite; RNA, Viral; Umbravirus; Virion; Virus Assembly
• ISSN: 0042-6822; 1096-0341
• DOI: 10.1006/viro.1998.9527

Groundnut rosette disease is caused by a complex of agents comprising groundnut rosette umbravirus (GRV), GRV satellite RNA (sat-RNA)groundnut rosette assistor luteovirus (GRAV). Both GRAV and GRV sat-RNA are needed for GRV to be aphid transmissible. To understand the role of GRAVGRV sat-RNA in the aphid transmission of GRV, encapsidation of GRV genomicsatellite RNAs has been studied using transgenicNicotiana benthamianaplants expressing GRAV coat protein (CP). GRAV CP expressed from a transgene was shown to package GRV genomicsatellite RNAs efficiently, giving a high yield of transcapsidated virus particles. GRV sat-RNA was absolutely essential for this process. GRV genomic RNA was not encapsidated by GRAV CP in the absence of the sat-RNA. Using different mutants of GRV sat-RNA, it was found that some property of full-length satellite RNA molecules, such as size or specific conformation rather than potential open reading frames, was required for the production of virus particles. A correlation between the ability of sat-RNA to stimulate encapsidation of GRV RNA by GRAV CPits capacity to promote aphid transmission of GRV was observed.