• The Plant Pathology Journal
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• 제26권4호
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• pp.328-339
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• 2010

A tobamovirus, Ribgrass mosaic virus (RMV), was identified newly from chinese cabbage (Brassica campestris L. pekinensis) in Korea. Virus disease incidence of RMV on chinese cabbage was 37.9% in alpine area on August in 1993. RMV induced the symptoms of necrotic ring spots, necrotic streak on midrib and malformation. RMV, Ca1 and Ca3 isolate, could infect 35 species out of 45 plants including Chenopodium amaranticolor. Physical properties of RMV Ca1 isolate were very stable as 10.8 over for dilution end point, $95^{\circ}C$ for temperature inactivation point and 18 weeks for longevity in vitro. RMV had the soil transmission rate of 75.0% for the chinese cabbages, 'Chunhawang' and 'Seoul' cultivars. The purified virions of RMV had the typical ultraviolet absorption spectrum of maximum at 260 nm and minimum at 247 nm. RMV of Ca1 isolate was related serologically with antisera of Tobacco mosaic virus (TMV)-Cym, TMV-O and Pepper mottle virus, but not related with antiserum of Odontoglossum ring spot virus. coat protein gene of RMV-Ca1, sized 473 nucleotides, encoded 158 amino acid residues. Nucleotide identity of RMV-Ca1 CP gene was 96.4% with RMV-Shanghai (GenBank accession No. of AF185272) from China and 96.0% with RMV-Impatiens (GenBank accession No. of AM040974) from Germany. Identity of amino acids between RMV-Ca1 and the two RMV isolates was 96.8%. Specific three primers were selected for rapid and easy genetic detection of RMV using Virion Captured (VC)/RT-PCR method.

• BMB Reports
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• 제41권5호
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• pp.376-381
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• 2008

The discovery of RNA silencing inhibition by virus encoded suppressors or low temperature leads to concerns about the stability of transgenic resistance. RNA-dependent RNA polymerase (RdRp) has been previously characterized to be essential for transgene-mediated RNA silencing. Here we showed that low temperature led to the inhibition of RNA silencing, the loss of viral resistance and the reduced expression of host RdRp homolog (NtRdRP1) in transgenic T4 progeny with untranslatable potato virus Y coat protein (PVY-CP) gene. Moreover, RNA silencing and the associated resistance were differently inhibited by potato virus X (PVX) and tobacco mosaic virus (TMV) infections. The increased expression of NtRdRP1 in both PVX and TMV infected plants indicated its general role in response to viral pathogens. Collectively, we propose that biotic and abiotic stress factors affect RNA silencing-mediated resistance in transgenic tobacco plants and that their effects target different steps of RNA silencing.