Submitted to: Virology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: March 18, 1997
Publication Date: N/A
Interpretive Summary: This manuscript describes a study of the genetics of a virus known as oat blue dwarf virus (OBDV). This virus possesses some abilities and disabilities which make it an excellent model for studying how viruses function and cause disease. The complete nucleotide sequence (genetic code) of OBDV was determined and compared to the nucleotide sequences of other viruses. We identified viral genes responsible for a variety of activities essential to reproduction of the virus. The means by which the viral genes are expressed was also examined. Strong similarities between OBDV and other known viruses, as well as unique properties, were identified. These analyses allowed us to identify known viruses (Tymoviruses) which appear to be most closely related to OBDV. This information will allow us to conduct comparative studies to help determine the molecular basis of how viruses control their own movement within plants and how host range is determined. This in turn will assist in the eventual development of better control measures for virus diseases.
Technical Abstract: The complete nucleotide sequence and genome organization of oat blue dwarf marafivirus (OBDV) were determined. The 6532 nucleotide genome encodes a putative 227 kDa polyprotein (p227) with sequence motifs similar to the methyltransferase, papain-like protease, helicase, and polymerase motifs present in the non-structural proteins of other positive strand RNA viruses. The 3' end of the open reading frame (ORF) that encodes p227 (ORF 227) also encodes the two capsid proteins: a 24 kDa capsid protein is presumably cleaved from the p227 polyprotein, whereas the 21 kDa capsid protein appears to be translated from a subgenomic RNA (sgRNA). Encoded amino acid and nucleotide sequence comparisons, as well as the OBDV genome expression strategy, show that OBDV closely resembles the tymoviruses. OBDV differs from the tymoviruses in its general biology, in its lack of a putative movement gene that overlaps the replication-associated genes, and in its fusion of the capsid gene sequences to the major ORF. OBDV also possesses a 3' poly(A) tail, as compared to the tRNA-like structures found in most tymoviral genomes. Due to the strong similarities in genome sequence and expression strategy, OBDV, and presumably the other marafiviruses, should be considered a member of the tymovirus lineage of the alpha-like plant viruses.