Authors
P. Rajakaruna and
S. Khandekar, Department of Biological Sciences, University of Toledo, Toledo, OH 43606;
T. Meulia, Molecular and Cellular Imaging Center, The Ohio Agricultural Research and Development Center, Wooster, OH 44691; and
S. M. Leisner, Department of Biological Sciences, University of Toledo, Toledo, OH 43606
ABSTRACT
Viruslike chlorotic ring spot symptoms and line patterns of unknown origin were observed on a greenhouse-grown turnip plant. The suspected virus was mechanically transmissible to plants in the Brassicaceae. Electron microscopic analysis revealed icosahedral particles approximately 28 nm in diameter. Reverse transcriptase--polymerase chain reaction (RT-PCR) analyses suggested that the pathogen is a comovirus, an observation that was confirmed by analysis of portions of the genomic sequence. This virus was provisionally named Turnip ringspot virus (TuRSV). Based on the RNA 1 sequence, TuRSV is most similar to Radish mosaic virus, another pathogen that infects members of the Brassicaceae. Arabidopsis thaliana is susceptible to TuRSV, and 12 out of the 23 ecotypes studied showed symptoms when inoculated with the virus. TuRSV induced a variety of responses on ecotypes from death to no infection. Some ecotypes showed one or two rounds of symptom display followed by recovery when inoculated with TuRSV. About half of the ecotypes (11/23) analyzed showed no symptoms when inoculated with TuRSV. Col-0 plants showed no symptoms, and infectious virus was not recovered from systemic leaves, although it could be detected by RT-PCR. Col-0 plants harboring mutations impairing the ethylene, jasmonic acid, or salicylic acid signaling pathways did not show symptoms when inoculated with TuRSV.
