Physiological Function of RDL1 and RDL2 Subunits of the Ionotropic GABA Receptor in the Spodoptera litura with the CRISPR/Cas9 System In Vivo .

In insect ionotropic γ-aminobutyric acid receptor (iGABAR) subunits, only resistance to dieldrin (RDL) can be individually and functionally expressed in vitro . In lepidopteran, two to three RDL subtypes are identified; however, their physiological roles have not been distinguished in vivo . In this study, Sl Rdl1 and Sl Rdl2 of S. litura were individually knocked out using CRISPR/Cas9, respectively. The mortality and larval and pupal duration of KO Sl Rdl1 and KO Sl Rdl2 were increased. The flight time and distance were increased by 43.30%-80.66% and 58.96%-198.22%, respectively, in KO Sl Rdl1. The GABA-induced current was significantly decreased by 53.57%-74.28% and 46.91%-63.34% in the ventral nerve cord, and the GABA titer was significantly reduced by 17.65%-28.05% and 19.85%-42.46% in KO Sl Rdl1 and KO Sl Rdl2, respectively. In conclusion, Sl Rdl1 and Sl Rdl2 are necessary for the transmission of GABA-induced neural signals; however, only Sl Rdl1 could regulate the flight capability of S. litura . Our results provided a new avenue to study lepidopteran iGABARs.