Construction of full-length cDNA clones to Soil-borne wheat mosaic virus RNA1 and RNA2, from which infectious RNAs are transcribed In vitro: virion formation and systemic infection without expression of the N-terminal and C-terminal extensions to the capsid protein.
The 19-kDa capsid protein (CP) of Soil-borne wheat mosaic furovirus (SBWMV) is encoded in the 5'-terminal region of RNA2. In addition to CP, two CP-related proteins are translated from SBWMV RNA2: (1) a 24-kDa protein (N-CP) with an N-terminal 40-amino-acid extension initiated at an upstream in-frame CUG codon; and (2) an 83-kDa protein (CP-RT) with an about 580-amino-acid, C-terminal extension by partial translational readthrough at the UGA termination codon at the end of the CP gene. We examined requirements for N-CP and CP-RT on virion formation and systemic infection in wheat plants using full-length cDNA clones, from which infectious RNA can be transcribed in vitro. RNA2 mutants, which could not synthesize N-CP, CP-RT, or either infected wheat plants systemically in combination with the wild-type RNA1 transcripts, produced rod-shaped virus particles in uninoculated upper leaves. Original mutations which abolished translation of N-CP and CP-RT were confirmed on RNA2 extracted from purified virus from the upper leaves by nucleotide sequence analysis. These results indicate that neither N-terminal nor C-terminal extensions to the CP are required for virion formation and systemic infection of SBWMV in wheat plants.
Yamamiya
A
A
Asian Center for Bioresources and Environmental Sciences (ANESC), Graduate School of Agricultural Life Sciences, Tokyo, Japan.
Shirako
Y
Y
D001483:Base Sequence; D002213:Capsid / Q000235:genetics*; D003001:Cloning, Molecular; D017931:DNA Primers; D018076:DNA, Complementary; D009029:Mosaic Viruses / Q000235:genetics* / Q000472:pathogenicity; D016297:Mutagenesis, Site-Directed; D010935:Plant Diseases; D018515:Plant Leaves / Q000821:virology; D014176:Protein Biosynthesis; D012367:RNA, Viral / Q000235:genetics*; D014158:Transcription, Genetic; D014908:Triticum / Q000821:virology*
D017931:DNA Primers; D018076:DNA, Complementary; D012367:RNA, Viral