Potato mop-top virus: the coat protein-encoding RNA and the gene for cysteine-rich protein are dispensable for systemic virus movement in Nicotiana benthamiana.
Full-length genomic cDNA clones of the Swedish isolate of Potato mop-top virus (PMTV) were transcribed in vitro using T7 RNA polymerase. The combination of RNA 1, 2 and 3 synthesized in the presence of m(7)GpppG cap analogue was infectious when inoculated onto Nicotiana benthamiana plants. Also, the combination of RNA 1 (encodes the viral replicase) with RNA 3 [encodes the triple gene block proteins and a small cysteine-rich protein (CRP)] was infectious and both RNAs moved systemically in N. benthamiana plants in the absence of RNA 2, which encodes the coat protein (CP). However, the yellow mosaic symptoms that typically developed following PMTV infection with all three RNAs were not observed in plants infected with RNA 1+RNA 3. Site-directed mutagenesis experiments revealed that expression of the putative CRP was not required for systemic infection and symptom induction in N. benthamiana. These data show that PMTV represents an example of a multipartite virus capable of establishing systemic infection without the CP-encoding RNA, and also without the putative CRP.
Savenkov
Eugene I
EI
Department of Plant Biology, Swedish University of Agricultural Sciences (SLU), S-750 07 Uppsala, Sweden.
Germundsson
Anna
A
Department of Plant Biology, Swedish University of Agricultural Sciences (SLU), S-750 07 Uppsala, Sweden.
Zamyatnin
Andrey A
AA
Department of Plant Biology, Swedish University of Agricultural Sciences (SLU), S-750 07 Uppsala, Sweden.
Sandgren
Maria
M
Department of Plant Biology, Swedish University of Agricultural Sciences (SLU), S-750 07 Uppsala, Sweden.
Valkonen
Jari P T
JPT
Department of Applied Biology, University of Helsinki, Finland.|Department of Plant Biology, Swedish University of Agricultural Sciences (SLU), S-750 07 Uppsala, Sweden.
D036022:Capsid Proteins / Q000235:genetics*; D003545:Cysteine; D018076:DNA, Complementary; D009068:Movement; D010942:Plant Viruses / Q000235:genetics / Q000378:metabolism*; D012367:RNA, Viral / Q000502:physiology*; D014026:Nicotiana / Q000821:virology*; D014158:Transcription, Genetic
D036022:Capsid Proteins; D018076:DNA, Complementary; D012367:RNA, Viral; D003545:Cysteine