Submitted to: Meeting Abstract
Publication Type: Abstract only
Publication Acceptance Date: 4/1/2004
Publication Date: 6/1/2004
Citation: Lewandowski, D., Adkins, S.T. The tubule forming NSm protein from tomato spotted wilt virus supports long-distance movement of tobacco mosaic virus (TMV) in tobacco in the presence of the TMV coat protein. American Society for Virology 23rd Annual Meeting. Abstract No. P40-7. Interpretive Summary:
Technical Abstract: Tobacco mosaic virus (TMV) coat protein (CP) and movement protein (MP) are required for long-distance movement of TMV in tobacco. TMV hybrids expressing the NSm ORF from Tomato spotted wilt virus were constructed to test whether this tubule forming, putative MP could functionally substitute for the TMV 30-kDa protein. In the first set of hybrids, the NSm ORF from a Florida isolate of TSWV was expressed from either the MP or CP subgenomic (sg) promoter. These free-RNA hybrids were capable of moving cell-to-cell in several Nicotiana species tested. Both hybrids were restricted to inoculated leaves of Nicotiana tabacum cv. Xanthi, but moved into upper leaves of N. benthamiana. In tobacco protoplasts, both TMV-TSWV hybrids formed tubules characteristic of this type of MP. Deletion of the C-terminus of NSm abolished tubule-formation in protoplasts and cell-to-cell movement. Fusion of GFP to the C-terminus of NSm (NSm-GFP) also destroyed the ability of NSm to form tubules. However, in protoplasts co-infected with a hybrid expressing NSm and the hybrid expressing NSm-GFP, the NSm-GFP fusion protein was detectable in tubules. Re-insertion of the entire TMV origin of assembly, CP sg promoter and the CP ORF into the hybrid expressing NSm from the MP sg promoter resulted in a virus that replicated similar to wild-type TMV, formed virions, and rapidly moved systemically in N. benthamiana. Interestingly, this hybrid also moved into upper leaves of tobacco. These results indicate that NSm can functionally substitute for the TMV 30-kDa protein for long-distance movement in tobacco.