Addition of nucleotides similar to deleted CAA repeats in the 5' non-coding region of tomato mosaic virus RNA following propagation.
Previously we made a series of deletion mutants in the 5' non-coding region of tomato mosaic tobamovirus (ToMV) RNA and checked their ability to replicate in tobacco protoplasts. Long deletions in this region caused the virus to lose the ability to replicate. Several mutants with deletions of about 10 nucleotides (short deletion mutants; SDM) retained the ability to replicate. In this study, we inoculated SDMs onto systemic host plants and observed their symptoms. One mutant (19/32) caused severe mosaic symptoms on some tobacco plants (Nicotiana tabacum cv. Samsun) but no symptoms on others. Virus accumulation in 19/32-inoculated plants paralleled the severity of symptoms. Four CAA repeat sequences were deleted in 19/32. Progeny 19/32 from plants showing severe systemic mosaic symptoms had acquired additional nucleotides in this region. We conclude that the CAA repeat sequence is related to the fitness of the virus population to replicate in whole plants rather than to translation of ToMV replicase genes.
Watanabe
Y
Y
Department of Biosciences, School of Science and Engineering, Teikyo University, Utsunomiya, Japan. watanabe@nasu.bio.teikyo-u.ac.jp
Ohnishi
J
J
Saitoh
H
H
Hosokawa
D
D
Okada
Y
Y
D000818:Animals; D001483:Base Sequence; D018551:Solanum lycopersicum / Q000821:virology; D008969:Molecular Sequence Data; D010947:Plants, Toxic; D016133:Polymerase Chain Reaction; D012367:RNA, Viral; D011817:Rabbits; D017384:Sequence Deletion; D014026:Nicotiana; D017898:Tobamovirus / Q000235:genetics* / Q000502:physiology; D018911:Trinucleotide Repeats; D014779:Virus Replication
D012367:RNA, Viral