Elsevier

Virus Research

Volume 123, Issue 1, January 2007, Pages 95-99
Virus Research

Short communication
Cocksfoot mottle virus P1 suppresses RNA silencing in Nicotiana benthamiana and Nicotiana tabacum

https://doi.org/10.1016/j.virusres.2006.07.013Get rights and content

Abstract

The Sobemovirus genome consists of positive sense, single-stranded polycistronic RNA. The 5′-terminal ORF, encoding the protein P1, is its most variable region. Sobemoviral P1 has been described as dispensable for replication but indispensable for systemic infection. The P1 of Rice yellow mottle virus-Nigerian isolate (RYMV-N) is the only RNA silencing suppressor reported for sobemoviruses until now. Using an agrobacterium-mediated transient assay, we demonstrate here that P1 of Cocksfoot mottle virus-Norwegian isolate (CfMV-NO) suppresses RNA silencing in Nicotiana benthamiana and Nicotiana tabacum, two non-host plants. CfMV-NO P1 was able to suppress the initiation and maintenance of silencing. The suppression of systemic silencing was weaker with CfMV-NO P1 than in the case of RYMV-N P1. In the case of suppression at the local level, the reduction in the amount of 25-nucleotide small interfering RNAs (siRNAs) was less pronounced for CfMV-NO P1 than it was when RYMV-N P1 was used. At the same time, we show that CfMV-NO P1 did not bind siRNAs.

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Acknowledgements

We thank Prof. D. Baulcombe at the Sainsbury Laboratory for N. benthamiana 16c line, pBIN61, GFP in pBIN61, P19 in pBIN61 and RYMV P1 in pBIN61, supplied by PBL. We are grateful to Dr. M. Prins and his group at Wageningen University, for technical support in gel-shift experiments with bacterial expressed proteins, for His-NS1 and N. benthamiana GFP-silenced line. Dr. D. Silhavy and his group at Agricultural Biotechnology Center (Gödöllö) are thanked for all the help in gel-shift experiments

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    These authors contributed equally to the work.

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