ARS | Publication request: The genome of the fire ant Solenopsis invicta

Submitted to: Proceedings of the National Academy of Sciences
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: November 12, 2010
Publication Date: January 31, 2011
Citation: Wurm, Y., Wang, J., Riba-Grognuz, O., Corona, M., Nygaard, S., Hunt, B.G., Ingram, K.K., Falquet, L., Nipitwattanaphon, M., Gotzek, D., Dijkstra, M.B., Oettler, J., Shih, C., Wu, W., Scotty Yang, C., Thomas, J., Beaudoing, E., Pradervand, S., Flegel, V., Fabbretti, R., Stockinger, H., Long, L., Farmerie, B., Oakey, J., Harkins, T., Boomsma, J.J., Pamilo, P., Yi, S.V., Heinze, J., Goodisman, M.A., Farinelli, L., Harshman, K., Hulo, N., Cerutti, L., Xenarios, I., Shoemaker, D.D., Keller, L. 2011. The genome of the fire ant Solenopsis invicta. Proceedings of the National Academy of Sciences. 10:1073.

Interpretive Summary: Fire ants are considered significant ecological, agricultural, and public health pest throughout their invasive range in the U.S.A. A Scientist at the Center for Medical, Agricultural, and Veterinary Entomology, USDA-ARS, Gainesville, Florida and scientists from several institutions around the world present a draft genome sequence of the fire ant Solenopsis invicta. Several unique aspects of the fire genome are described that are likely linked to the complex social behavior of this species. These extensive sequence data provide a new rich resource for functional genomic studies of this pest ant.

Technical Abstract: Ants have evolved very complex societies and are key ecosystem members. Some of them are also major pests, as exemplified by the fire ant Solenopsis invicta. We present here the draft genome of S. invicta, assembled from 454 and Illumina reads obtained from a focal haploid male and his brothers. In contrast to other insects, and similar to the honey bee, S. invicta has only two orthologous ILPs and two insulin/IGF-1 receptors. Phylogenetic analyses suggest that these two receptors resulted from an ancient duplication, and that subsequent losses occurred in Diptera and Nasonia. S. invicta also has a functional DNA methylation system, as well as a single putative telomerase ortholog. EST data indicate that this S. invicta telomerase ortholog has at least four strongly supported splice-forms that differ in their use of two sets of mutually exclusive exons. We identified 320 putative Olfactory Receptors, the largest repertoire reported so far in insects. Comparative analyses also reveal an expansion of a specific family of lipid processing genes, possibly associated with the particular mode of colony founding of ants. Furthermore, the fire ant genome harbors four adjacent copies of vitellogenin. Phylogenetic analysis reveals that an ancestral vitellogenin gene first underwent duplication, followed by possibly independent duplications of each of the daughter vitellogenins. The vitellogenin genes have undergone subfunctionalization with queen- and worker-specific expression possibly reflecting differential selection acting on the queen and worker castes. Several unique aspects of the fire genome are likely linked to the complex social behavior of this species.