Submitted to: Plant Pathology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: April 19, 2004
Publication Date: October 1, 2005
Citation: Robertson, N.L. 2004. The biology of a new virus isolated from lupinus nootkatensis plants in Alaska. Plant Pathology. 53:569-576. Interpretive Summary: Interpretive Summary Studies concerning viruses in native plants are scarce throughout the world. During a 1999 survey for plant viruses in native plants of Alaska, natural lupine plants (Lupinus nootkatensis) in the Hatcher Pass region of the Talkeetna Mountains were observed with virus-like symptoms on their leaves. The objective was to isolate, identify, and characterize the causal agent from diseased plants, and to examine the epidemiology on the site from 2000-03. A new plant virus was isolated from lupine plants and based on physico-chemical data and partial sequence information, the virus was identified as a member of the family Tombusviridae, and tentatively of the genus Carmovirus. The experimental plant host range was limited to only species in Fabaceae that resulted in mortality to nearly all of the infected exotic lupine species and Cicer arietinum (chickpea). This is the first report of a virus from Tombusviridae infecting lupine species in a natural environment, and one of the few reported incidences of this type of virus infecting Fabaceae plants in a non-tropical climate. The virus did not appear to have an adverse effect on its perennial natural host, in that most infected plants appeared normal in height, and did not transmit the virus through its seed. However, based on the high incidence of mortality in infected exotic lupine species and chickpeas, it is important that these plant species not be exposed to this new virus.
Technical Abstract: Technical Abstract A new virus named Nootka lupine vein-clearing virus (NLVCV) was isolated from native lupine plants confined to a relatively small area in the Talkeetna Mountains of south-central Alaska. Spherical particles about 30 nm in diameter were isolated from these leaves. Virions contained a single-stranded RNA about 4.0 to 4.2 kb and one species of capsid protein estimated to be about 40 kDa. The double-stranded RNA profile from naturally infected leaves consisted of three major bands approximately 4.2, 1.9, and 1.5 kbp. Protein extractions from either sap or virions of diseased plants reacted to polyclonal antiserum made against virions in western blot assays. A predicted PCR product about 500 bp was synthesized from virion RNA using primers that specifically targeted the carmovirus-related RNA-dependent-RNA polymerase gene. The nucleotide sequence of the amplified DNA did not match any known virus, but contained short regions of identity to several carmoviruses. Host range tests found that only species belonging to Fabaceae were susceptible by NLVCV mechanical inoculation. Based upon the given properties of the dsRNA profile, and size of the virion RNA genome and capsid protein, and the similarity of the polymerase gene to other carmoviruses, it is suggested that NLCVV is a newly described virus in the family Tombusviridae, and tentatively of the genus Carmovirus.