ARS | Publication request: A PROBABLE EVOLUTIONARY LINK BETWEEN THE MARAFIVIRUSES AND THE TYMOVIRUSES.

Submitted to: Phytopathology
Publication Type: Abstract Only
Publication Acceptance Date: March 31, 1995
Publication Date: N/A

Technical Abstract: The Marafiviruses are a small group of monopartite, (+) sense, RNA viruses reported to replicate in their leafhopper vectors as well as in their plant hosts. Since very little is known about these viruses, we began an investigation of the molecular biology of oat blue dwarf virus (OBDV), a Marafivirus which can be found annually in oat, barley, and flax in the upper Midwest. Clones representing more than half of the OBDV genome were obtained using oligo-dT primed cDNA synthesis. The remaining 5'-end sequence was cloned after ligation-anchored PCR. Extensive similarities between OBDV and the Tymoviruses were found in genome sequence and organization. Similarities in nonstructural gene organization and encoded amino acid sequences were particularly strong in putative protease, helicase, and polymerase domains. Cytidine content was comparable to that typical of Tymoviruses. A strong similarity to the 'Tymobox' also was found, both in nucleotide sequence (81%) and relative genome position. The observed levels of similarity were surprising considering the biological distinctions between these two virus groups. Our results have significant implications for the evolution of the Marafi- and Tymoviruses.