Submitted to: Archives of Virology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/20/2012
Publication Date: 6/4/2012
Citation: Agindotan, B.O., Gray, M.E., Hammond, R., Bradley, C.A. 2012. Complete genome sequence of switchgrass mosaic virus, a member of a proposed new species in the genus Marafivirus. Archives of Virology. DOI: dx.doi.org/10.1007/s00705-012-1354-3. Interpretive Summary: Plants are a source of chemicals that can be used to produce ethanol. The perennial grass, switchgrass, has great potential for production of ethanol as a biofuel. We characterized a virus associated with mosaic symptoms in switchgrass and found it to be closely related to an insect-transmitted virus that infects corn. The mosaic disease has the potential to reduce switchgrass biomass yield, and by extension, reduce the amount of ethanol from this crop. These results will be of interest to plant pathologists and scientists involved in production of bioenergy crops.
Technical Abstract: The complete genome sequence of a virus recently detected in switchgrass (Panicum virgatum) was determined and was found to be closely related to Maize rayado fino virus (MRFV), genus Marafivirus, family Tymoviridae. The genomic RNA is 6408 nucleotides long, excluding the poly (A) tail, and encodes three predicted open reading frames (ORFs) of M(r) 227 kDa, 43.9 kDa, and 31.5 kD, respectively. The complete genome shares 76% nt sequence identity with MRFV which contains 2 predicted ORFs. The switchgrass virus ORF2 nt and encoded protein aa sequences are 49% and 77% identical to those of the ORF2 of MRFV. The virus encoded polyprotein (ORF1) and capsid protein (CP) aa sequences are 83% and 74-80% identical, respectively, to those of MRFV. Although closely related to MRFV, the switchgrass CP aa forms a separate clade from the CP of several isolates of MRFV. Based on the International Committee on the Taxonomy of Viruses (ICTV) sequence-related criteria for delineation of species within the genus Marafivirus, the virus qualifies as a new species and the name Switchgrass mosaic virus (SwMV) is proposed.