Down-regulation of groundnut rosette virus replication by a variant satellite RNA.
Symptom production in groundnut plants infected with groundnut rosette virus (GRV) depends on the presence of satellite RNA (sat-RNA) in the GRV culture, and sat-RNA variants that induce only mild symptoms are known. One such variant drastically diminished the replication of GRV genomic RNA in infected Nicotiana benthamiana plants. This down-regulating ability did not involve either of the two open reading frames in the sat-RNA but was controlled by a region near its 5' end, which is required for sat-RNA replication. When N. benthamiana plants were inoculated with GRV and the mild satellite and challenged by inoculation with a GRV isolate (YB) containing a sat-RNA that induces yellow blotch symptoms, no symptoms appeared and little GRV genomic RNA or sat-RNA was detected in the plants, provided the two inoculations were no more than 2 days apart. A GRV isolate containing a sat-RNA that neither induces symptoms in N. benthamiana nor affects genomic RNA accumulation also provided protection against yellow blotch symptom production if inoculated before or up to 2 days after isolate YB. However, in this case protection ws incomplete and both GRV RNA and sat-RNA accumulated to normal levels. It is suggested that sequences from the mild sat-RNA may provide a novel source of resistance against rosette disease.
Taliansky
M E
ME
Scottish Crop Research Institute, Invergowrie, Dundee, United Kingdom.
Robinson
D J
DJ
D002874:Chromosome Mapping; D015536:Down-Regulation; D014644:Genetic Variation; D010942:Plant Viruses / Q000502:physiology*; D012328:RNA Viruses / Q000502:physiology*; D019244:RNA, Satellite / Q000235:genetics / Q000502:physiology*; D012367:RNA, Viral / Q000378:metabolism; D014762:Viral Interference; D014779:Virus Replication
D019244:RNA, Satellite; D012367:RNA, Viral