Intersex regulates larval growth and wing development in Agrotis ipsilon

The intersex gene functions at the bottom of sex determination hierarchy with the doublesex to implement somatic sexual differentiation in Drosophila melanogaster. However, little is known about other biological functions of this gene in animals. In this study, we evaluated expression of intersex in the black cutworm Agrotis ipsilon. We found that A. ipsilon intersex is expressed in multiple tissues and is highly expressed between the third and sixth instar larvae. In addition, knock-out of intersex using CRISPR/Cas9 technology caused delayed larval growth, pupal deformity, and defects in the imaginal disc. Notably, adult mutants had normal sexual differentiation but defects in the development of legs and wings, different than phenotypes of intersex mutants from other species including D. melanogaster. This is also the first report that intersex functions in larval growth. These results indicate that intersex is a novel potential gene target for control of A. ipsilon and other pests.