VIEW ARTICLE

Etiology

Purification and Partial Characterization of a Carlavirus from Taraxacum officinale. Lois J. Johns, Graduate student, Department of Plant Science, University of British Columbia, Canada, Present address: Agriculture Canada, Research Station, Vancouver, British Columbia, Canada V6T 1X2; Phytopathology 72:1239-1242. Accepted for publication 17 February 1982. This article is in the public domain and not copyrightable. It may be freely reprinted with customary crediting of the source. The American Phytopathological Society, 1982.. DOI: 10.1094/Phyto-72-1239.

A carlavirus was isolated from naturally infected dandelion (Taraxacum officinale) in the Okanagan Valley, British Columbia. In a survey of potential hosts, this virus was found to produce local and systemic symptoms in Chenopodium amaranticolor and C. quinoa and local lesions in Gomphrena globosa. The carlavirus for which the name dandelion latent virus (DLV) is proposed, has flexuous particles with normal length 640 nm and width 12–13 nm. A purification schedule was developed that yielded 20–30 mg of DLV per kilogram of infected C. quinoa tissue. Partially purified preparations of DLV have a single nucleoprotein component in sucrose and cesium chloride density gradients. The molecular weight of the RNA is 2.5 × 10 ⁶. The UV absorption spectrum has a maximum at 259 nm and a minimum at 245 nm. The A_max/A_min is approximately 1.1 and the A₂₆₀/A₂₈₀ is 1.4. In sap from DLV-infected C. quinoa, the thermal inactivation point was 75–80 C, the infectivity dilution end point was 10^–5 – 10^–6, the longevity in vitro was 4–5 days at 23 C, 28–56 days at 4 C, and >2 yr in a lyophilized state. DLV was transmitted nonpersistently by the aphid, Myzus persicae. It was not seed transmitted in dandelion or C. quinoa. By tube precipitin serology, antiserum prepared against DLV had a maximum homologous titer of 40,960. Two carlaviruses that caused similar systemic chlorosis in C. quinoa, a Peruvian strain of potato virus S and helenium virus S, were purified for comparative serological testing. DLV is related serologically to potato virus S and distantly related to chrysanthemum virus B, helenium virus S, and narcissus latent virus.