A single amino acid substitution in the coat protein of cucumber mosaic virus induces chlorosis in tobacco.
Some strains of cucumber mosaic virus (CMV) induce a bright yellow/white chlorosis in tobacco instead of the light green/dark green mosaic induced by most CMV strains. This property is controlled by RNA 3 of this tripartite virus. Recombination between cDNA clones of RNA 3 from a green mosaic strain, Fny-CMV, and a chlorotic strain, M-CMV, and inoculation of infectious transcripts of the chimeric RNAs 3, together with RNAs 1 and 2 of Fny-CMV, localized the chlorosis induction domain to a region of the coat protein gene containing two nucleotide differences. Site-directed mutagenesis of one nucleotide to change the codon for Leu129 in the M-CMV coat protein to Pro129 of Fny-CMV changed the phenotype from chlorotic to green mosaic, whereas the opposite change in phenotype was observed when the Pro129 in the Fny-CMV coat protein was altered to Ser129. Thus, the local secondary structure surrounding amino acid 129 rather than a particular amino acid per se is involved in chlorosis induction.
Shintaku
M H
MH
Department of Plant Pathology, Cornell University, Ithaca, New York 14853.
Zhang
L
L
Palukaitis
P
P
D000595:Amino Acid Sequence; D001483:Base Sequence; D002213:Capsid / Q000737:chemistry* / Q000235:genetics; D002734:Chlorophyll / Q000378:metabolism*; D004279:DNA, Viral; D008969:Molecular Sequence Data; D009029:Mosaic Viruses / Q000235:genetics / Q000502:physiology*; D010641:Phenotype; D010947:Plants, Toxic; D017433:Protein Structure, Secondary; D014026:Nicotiana / Q000378:metabolism / Q000382:microbiology*
D004279:DNA, Viral; D002734:Chlorophyll