Identification of the odorant binding proteins of Western Flower Thrips (<i>Frankliniella occidentalis</i>), characterization and binding analysis of <i>FoccOBP3</i> with molecular modelling, molecular dynamics simulations and a confirmatory field trial

Olfactory systems are indispensable for insects as they, including Western Flower Thrips (<i>Frankliniella occidentalis</i>), use olfactory cues for ovipositing and feeding. <i>F. occidentalis</i> use odorant binding proteins (OBPs) to transport semiochemicals to odorant receptors to induce a behavioural response from the sensillum lymph of the insect’s antennae. This study identifies four OBPs of <i>F. occidentalis</i> and analyses their expression at three stages of growth: larvae, adult males and adult females. Further, it investigates the presence of conserved motifs and their phylogenetic relationship to other insect species. Moreover, <i>FoccOBP3</i> was <i>in silico</i> characterized to analyse its structure along with molecular docking and molecular dynamics simulations to understand its binding with semiochemicals of <i>F. occidentalis</i>. Molecular docking revealed the interactions of methyl isonicotinate, p-anisaldehyde and (S)-(-)-verbenone with <i>FoccOBP3</i>. Moreover, molecular dynamics simulations showed bonding stability of these ligands with <i>FoccOBP3,</i> and field trials validated that Lurem TR (commercial product) and p-anisaldehyde had greater attraction as compared to (S)-(-)-verbenone, given the compound’s binding with <i>FoccOBP3</i>. The current study helps in understanding the tertiary structure and interaction of <i>FoccOBP3</i> with lures using computational and field data and will help in the identification of novel lures of insects in the future, given the importance of binding with OBPs.