A Yeast RNA-Interference Pesticide Targeting the <i>Irx</i> Gene Functions as a Broad-Based Mosquito Larvicide and Adulticide
Keshava Mysore,
Longhua Sun,
Limb K. Hapairai,
Chien-Wei Wang,
Jessica Igiede,
Joseph B. Roethele,
Nicholas D. Scheel,
Max P. Scheel,
Ping Li,
Na Wei,
David W. Severson,
Molly Duman-Scheel
Affiliations
Keshava Mysore
Department of Medical and Molecular Genetics, Indiana University School of Medicine, Raclin-Carmichael Hall, 1234 Notre Dame Ave., South Bend, IN 46617, USA
Longhua Sun
Department of Medical and Molecular Genetics, Indiana University School of Medicine, Raclin-Carmichael Hall, 1234 Notre Dame Ave., South Bend, IN 46617, USA
Limb K. Hapairai
Department of Medical and Molecular Genetics, Indiana University School of Medicine, Raclin-Carmichael Hall, 1234 Notre Dame Ave., South Bend, IN 46617, USA
Chien-Wei Wang
Eck Institute for Global Health, The University of Notre Dame, Notre Dame, IN 46556, USA
Jessica Igiede
Eck Institute for Global Health, The University of Notre Dame, Notre Dame, IN 46556, USA
Joseph B. Roethele
Department of Medical and Molecular Genetics, Indiana University School of Medicine, Raclin-Carmichael Hall, 1234 Notre Dame Ave., South Bend, IN 46617, USA
Nicholas D. Scheel
Eck Institute for Global Health, The University of Notre Dame, Notre Dame, IN 46556, USA
Max P. Scheel
Department of Medical and Molecular Genetics, Indiana University School of Medicine, Raclin-Carmichael Hall, 1234 Notre Dame Ave., South Bend, IN 46617, USA
Ping Li
Department of Medical and Molecular Genetics, Indiana University School of Medicine, Raclin-Carmichael Hall, 1234 Notre Dame Ave., South Bend, IN 46617, USA
Na Wei
Eck Institute for Global Health, The University of Notre Dame, Notre Dame, IN 46556, USA
David W. Severson
Department of Medical and Molecular Genetics, Indiana University School of Medicine, Raclin-Carmichael Hall, 1234 Notre Dame Ave., South Bend, IN 46617, USA
Molly Duman-Scheel
Department of Medical and Molecular Genetics, Indiana University School of Medicine, Raclin-Carmichael Hall, 1234 Notre Dame Ave., South Bend, IN 46617, USA
Concerns for widespread insecticide resistance and the unintended impacts of insecticides on nontarget organisms have generated a pressing need for mosquito control innovations. A yeast RNAi-based insecticide that targets a conserved site in mosquito Irx family genes, but which has not yet been identified in the genomes of nontarget organisms, was developed and characterized. Saccharomyces cerevisiae constructed to express short hairpin RNA (shRNA) matching the target site induced significant Aedes aegypti larval death in both lab trials and outdoor semi-field evaluations. The yeast also induced high levels of mortality in adult females, which readily consumed yeast incorporated into an attractive targeted sugar bait (ATSB) during simulated field trials. A conserved requirement for Irx function as a regulator of proneural gene expression was observed in the mosquito brain, suggesting a possible mode of action. The larvicidal and adulticidal properties of the yeast were also verified in Aedes albopictus, Anopheles gambiae, and Culexquinquefasciatus mosquitoes, but the yeast larvicide was not toxic to other nontarget arthropods. These results indicate that further development and evaluation of this technology as an ecofriendly control intervention is warranted, and that ATSBs, an emerging mosquito control paradigm, could potentially be enriched through the use of yeast-based RNAi technology.
