A Gustatory Receptor GR8 Tunes Specifically to D-Fructose in the Common Cutworm .

Gustatory receptors (GRs) are crucial in the peripheral coding of the non-volatile compounds in insects, and thus play important roles in multiple behaviors including feeding, mating, and oviposition. However, little research has been done on GRs in lepidopteran pests. In the current work with , an important worldwide crop's pest, a candidate fructose GR gene () was cloned in full length, and its spatial and temporal expression profiles were determined by quantitative real-time PCR (qPCR). It revealed that was highly expressed in antennae of both male and female adults, as well as in larva of first, fifth and sixth instar. Functional analyses were further conducted using the oocyte system. responded specifically to D-fructose among 12 tested sugar compounds. In addition, the behavioral assay demonstrated that both female and male moths could respond with proboscis extension behavior to D-fructose applied onto the antenna, but females showed higher sensitivity than males. The results provide an important base for further elucidation of molecular mechanisms of gustation, and a potential target for development of feeding interfering technique in .