3.2 Development of larvae and food preference
After rearing for five consecutive generations, no difference between the knockout larvae (GOBP1, GOBP2 or GOBP1/2) with WT in pupa and emergence rate, indicating it does not affect the viability of this insect under our rearing conditions (Supplementary Table S3). However, after gene knockout, these larvae diverged in artificial diet choice (Figure 2). When the GOBP1 gene was knocked out, although the larvae had a decline in food selection, it did not reach a significant level, while the larvae that knocked out the GOBP2 or GOBP1/2 genes had apparent differences in food selection. It shows that knocking out of GOBP2 and GOBP1/2 genes affects the larvae sensitivity to food odorants.
3.3 Comparison ofEAG response to odorants of WT andhomozygous strain
We investigated antenna responses to host-plant odorants and some chemicals to determine whether the homozygous strain still detects previous odorants compared with WT strain. EAG was used to test the response to different chemicals. The EAG responses to parts of compounds in both male and female homozygous strain were strongly reduced or absent (Figure 3a). However, compared with males, when the genes were knocked out, female adults respond more strongly to the odorants tested. It shows that females are more sensitive to odorant types and some odorants than males. However, no matter which gene is knocked out, male sensitivity to the odor of sex pheromone has decreased, while females do not respond to it. We further analyzed the correlation between the three homozygous strains with WT strain by using EAG data. The results showed that EAG response of GOBP1/2 strain and WT strain is the highest (Figure 3b), indicating that the GOBP1 population is the least sensitive to odorants. It also indicates that when both genes are knocked out, the types of responses to odorants are significantly reduced. In addition, compared with the GOBP1 strain, the GOBP2 strain has a better correlation with the WT strain, indicating that GOBP2 gene knockout can also greatly reduce the sensitivity to multiple test odorants.