Figure 2

Olfactory evidences of H. halys in sensing linalool oxide. (A) Results of electroantennogram tests with linalool oxide. Lower-case letters indicate significant differences among tested dosages in either male or female adults. (GLM and Tukey HSD multiple comparison. P < 0.05. Error bars indicate ± s.e.m.) (B) Phylogenetic analysis of putative linalool sensing odorant receptors of H. halys by referring to ORs from A. lucorum, S. furcifera, C. lectularius, D. melanogaster, B. mori, M. separata, and H. armigera. The evolutionary history was inferred by using the Maximum Likelihood method and the JTT matrix-based model. The tree with the highest log likelihood (− 2,980,075.06) is shown. Initial tree(s) for the heuristic search were obtained automatically by applying Neighbor-Join and BioNJ algorithms to a matrix of pairwise distances estimated using the JTT model, and then selecting the topology with superior log likelihood value. This analysis involved 374 amino acid sequences. There were a total of 1344 positions in the final dataset. Evolutionary analyses were conducted in MEGA X. (C) Structural predictions of four putative linalool sensing ORs in H. halys, with modeling re-constructed referring to known Cryo-EM structures of insect ORco (Apocrypta bakeri ORco: 6c70.1.A) Schematic shows representative 7-TMD structure of insect OR. All four ORs showed 7-TMD structures and potentially tetramer binding activities. Predictions were done with SWISS-MODEL. (D) Alignment of the four H. halys ORs with referring to most related linalool sensing ORs in Drosophila and cotton bollworm. Conservations of amino acid residues were indicated with colors.