Identifying a New Target for Bt OBP8: Discovery of a Small Amino Ketone Molecule Containing Benzothiazole Fragments.

Insects rely on odorant-binding proteins (OBPs) for chemical perception, making OBPs a promising target for studying attractants and repellents of pests, such as Bemisia tabaci . However, no reports have reported using B. tabaci OBPs ( Bt OBPs) as pesticide screening targets. To fill this gap, we obtained Bt OBP8 through prokaryotic expression and purification. Then, we confirmed its identity using western blotting and mass spectrometry. Next, we used the sitting drop and hanging drop methods to screen its crystal conditions. Using microscale thermophoresis and isothermal titration calorimetry, we identified the highest affinity ligand, 3l , from 30 compounds. Furthermore, point mutation techniques identified Val119 as a key amino acid residue in binding 31 to Bt OBP8. Finally, we tested the bioactivity of B. tabaci Mediterranean and found that 3l more effectively inhibits the bioactivity of B. tabaci MED than imidacloprid. This study presents a new approach for developing green insecticides specific to B. tabaci MED by targeting OBPs. Conclusively, identifying and targeting specific OBPs can create more targeted and effective pest control strategies without relying on toxic chemicals.