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ARS Home » Southeast Area » Gainesville, Florida » Center for Medical, Agricultural and Veterinary Entomology » Imported Fire Ant and Household Insects Research » Research » Publications at this Location » Publication #208693
Title: A new Positive-strand RNA Virus with Unique Genome Characteristics from the Red Imported Fire Ant, Solenopsis invicta

Author
item Valles, Steven
item Strong, Charles
item Hashimoto, Yoshifumi

Submitted to: Virology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/22/2007
Publication Date: 5/3/2007
Citation: Valles, S.M., Strong, C.A., Hashimoto, Y. 2007. A new Positive-strand RNA Virus with Unique Genome Characteristics from the Red Imported Fire Ant, Solenopsis invicta. Virology. 365(2):457-463.

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) have discovered a new virus infecting the imported fire ant. This is only the second virus discovered to infect the red imported fire ant. The entire genome was sequenced and studies suggest that the virus (SINV-2) could potentially serve as a biological control agent for fire ants.

Technical Abstract: We report the discovery of a new virus with unique genome characteristics from the red imported fire ant, Solenopsis invicta. This represents the second virus identified from this ant species. It is provisionally named Solenopsis invicta virus 2 (SINV-2). The SINV-2 genome was constructed by compiling sequences from successive 5' RACE reactions, a 3' RACE reaction, and expressed sequence tag, c246 (EH413675), from a fire ant expression library. The SINV-2 genome structure was monopartite, polycistronic and RNA-based. The genome consensus sequence (accession number EF428566) was 11,303 nucleotides in length, excluding the poly(A) tail present on the 3' end. Analysis of the genome revealed 4 major open reading frames (ORFs; comprised of ' 100 codons) and 5 minor ORFs (comprised of 50-99 codons) in the sense orientation. No large ORFs were found in the inverse orientation suggesting that the SINV-2 genome was from a positive-strand, single-stranded RNA (ssRNA) virus. Further evidence for this conclusion includes, abolished RT-PCR amplification by RNase treatment of SINV-2 nucleic acid template, and failure to amplify without first conducting cDNA synthesis. Blastp analysis indicated that ORF 4 contained conserved domains of an RNA-dependent RNA polymerase, helicase, and protease, characteristic of picorna-like RNA viruses. However, the protease domain and putative structural proteins (ORFs 1, 2, and 3) were less well conserved. Phylogenetic analysis of the RdRp, helicase, and ORF 1 indicate unique placement of SINV-2 exclusive from the Dicistroviridae, iflaviruses, Picornaviridae, and small plant RNA viruses.