Submitted to: Book Chapter
Publication Type: Book / Chapter
Publication Acceptance Date: May 16, 2001
Publication Date: January 1, 2004
Citation: Edwards, M.C. 2004. Oat blue dwarf. In: Lapierre, H., Signoret, P. editors. Viruses and Virus Diseases of Poaceae (Graminae). Institut National de la Recherche Agronomique, France. p. 483-486. Technical Abstract: Symptoms of Oat blue dwarf virus (OBDV) were first described in Minnesota USA in 1951, but it has been reported in Canada and Europe as well. Virions are isometric, non-enveloped particles approximately 28-30 nm in diameter and contain a single, linear, positive-sense RNA of 6509 nucleotides with a poly(A) tail. A single large ORF accounts for 95% of the genome and encodes a 227 kDa polyprotein with methyltransferase, papain-like protease, helicase, and polymerase motifs. The carboxy terminal region of this large polyprotein comprises a 24 kDa capsid protein that is apparently derived by proteolytic cleavage. Nested within the 3' terminus of the p227 ORF, and coterminal with it, is an ORF encoding a 21 kDa capsid protein. OBDV is a member of the genus Marafivirus, and as such is related to both Maize rayado fino virus (MRFV) and Bermuda grass etched-line virus (BELV). Sequence similarities also have been recently identified between OBDV and Poinsettia mosaic virus (a tentative member of the tymoviruses) and several viruses of grapevine (Grapevine fleck virus, Grapevine asteroid mosaic-associated virus, Grapevine red globe virus). OBDV is transmissible only by its leafhopper vector, Macrosteles fascifrons (USA) or M. laevis (Europe), in which it also replicates. The virus is limited to the phloem of its plant hosts. Known host range includes 57 plant species in 7 families, and includes both monocots and dicots. Natural hosts include cereal crops, flax, and several weeds and wild grasses. In North America, virus incidence normally ranges from a trace to less than 5%, and therefore its economic impact appears to be minimal.