Submitted to: Phytopathology
Publication Type: Abstract Only
Publication Acceptance Date: 4/18/2003
Publication Date: 6/6/2003
Citation: Keller, K.E., Hampton, R.O., Meyers, J.R., Tzanetakis, I.E., Dean, D., Martin, R.R. 2003. Pea calico- old players, new game?. Phytopathology. 93:S44. Interpretive Summary: An unusual pea disease was observed in the Willamette Valley in Oregon. Attempts to characterize the causal agent(s) of this disease have been carried out. In electron microscopy the symtomatic tissue appears disorganized but there were no obvious virus particles observed. Symtpomatic plants tested negative for 12 common pea viruses in ELISA. A disease agent was transmitted from symptomatic pea to pea, sweet pea, faba bean and Nicotiana benthamiana. The dsRNA pattern suggested a luteovirus/umbravirus mixed infection. Using RT-PCR we could consistently detect pea enation mosaic virus 2 (an umbravirus) and either pea enation mosaic virus 1 or beet chlorosis virus. The vector for the disease agents is being investigated.
Technical Abstract: An atypical pea disease was observed in Oregon's Willamette Valley. Electron microscopy of thin sections revealed only cellular disorganization. Antisera to 12 common pea viruses failed to detect any viruses by DAS-ELISA in mechanically maintained isolates. In host range studies 3 legumes and Nicotiana benthamiana were the only plants infected out of 65 plant species tested. This information and the pattern of dsRNA isolated from symptomatic peas prompted us to investigate an umbra-/luteovirus role in calico development. RT/PCR primers were designed to detect luteovirus, umbravirus and umbravirus satellite RNAs. Calico symptoms in the field correlated with a combination of Pea enation mosaic virus (PEMV)-1 (luteolike) and PEMV-2 (umbra) and the Beet chlorosis luteovirus infection. Satellite RNA was also detected. Current studies focus on vector transmission and the unique interactions that occur between umbra- and luteoviruses.