Mutagenesis mediated by CRISPR/Cas9 in the red imported fire ant, Solenopsis invicta

CRISPR/Cas9 mediated mutagenesis has revolutionized the testing of gene function in both model and non-model organisms. The red imported fire ant, Solenopsis invicta, is the best-studied ant species because of their painful sting, aggressive nature, and their detrimental effects on invaded ecosystems. We have developed a microinjection protocol for CRISPR/Cas9 mutagenesis of fire ant embryos. As a proof-of-principle we generated individuals mosaic for the knockout of Sinv-spitz or Gp-9. We verified that many injected individuals carry mutations, often to high frequency of the cells within the individual. Observations at the first instar larval stage indicate that mutating Sinv-spitz does not produce a loss of oenocyte phenotype, as would have been expected based on the homologous function of the fruit fly, Drosophila melanogaster, spitz. Our success indicates that CRISPR/Cas9 mutagenesis should be a useful technique for studying gene function in the fire ant at the individual and possibly social levels.