Submitted to: Virology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/9/2004
Publication Date: 10/4/2004
Citation: Valles, S.M., Strong, C.A., Dang, P.M., Hunter, W.B., Pereira, R.M., Oi, D.H., Shapiro, A.M., Williams, D.F. A picorna-like virus from the red imported fire ant, Solenopsis invicta: initial discovery, genome sequence, and characterization. Virology. 328:151-157.
Interpretive Summary: The red imported fire ant was introduced into the United States in the 1930s and currently infests about 300 million acres. It causes significant economic losses in livestock and agricultural production and poses a serious threat to human health. USDA-ARS scientists at the Center for Medical, Agricultural and Veterinary Entomology (Gainesville, FL) and the Horticulture and Breeding Research Laboratory (Ft. Pierce, FL) have discovered the first virus infecting the imported fire ant. The entire genome was sequenced and studies suggest that the virus (SINV-1) may be an excellent biological control agent for fire ants. An invention disclosure was submitted to the office of technology transfer for patent consideration (docket number 0106.04).
Technical Abstract: We report the first discovery and genome sequence of a virus infecting the red imported fire ant, Solenopsis invicta. The 8,026 nucleotide, polyadenylated, RNA genome encoded two large open reading frames (ORF1 and ORF2), flanked and separated by 27, 223, and 171 nucleotide untranslated regions, respectively. The predicted amino acid sequence of the 5' proximal ORF1 (nucleotides 28 to 4,218) exhibited significant identity and possessed consensus sequences characteristic of the helicase, cysteine protease, and RNA-dependent RNA polymerase sequence motifs from picornaviruses, picorna-like viruses, comoviruses, caliciviruses, and sequiviruses. The predicted amino acid sequence of the 3' proximal ORF2 (nucleotides 4390 to 7803) showed similarity to structural proteins in picorna-like viruses, especially the acute bee paralysis virus. Electron microscopic examination of negatively stained samples from SINV-1-infected fire ants revealed isometric particles with a diameter of 31 nm, consistent with Picornaviridae. A survey for the fire ant virus from areas around Florida revealed a pattern of fairly widespread distribution. Among 168 nests surveyed, 22.9% were infected. The virus was found to infect all fire ant caste members and developmental stages, including eggs, early (1st-2nd) and late (3rd-4th) instars, worker pupae, workers, sexual pupae, alates (' and '), and queens. The virus, tentatively named Solenopsis invicta virus (SINV-1), appears to belong to the picorna-like viruses. We did not observe any perceptible symptoms among infected nests in the field. However, in every case where an SINV-1-infected colony was excavated from the field with an inseminated queen and held in the laboratory, all of the brood in these colonies died with 3 months.