International .Journal of Biological Macromolecules, 2023,https:// doi: 10.1016/j.ijbiomac.2023.124744  

Abstract

Organic fertilizers-derived volatiles attract  Holotrichia parallela  during oviposition. However, the mechanisms underlying the perception of oviposition cues in  H. parallela  remain unclear. Here,  H. parallela  odorant-binding protein 3 (HparOBP3) was identified as a key OBP. Bioinformatics analysis showed that  HparOBP3  clustered together with  Holotrichia oblita  OBP8.  HparOBP3 was mainly expressed in the antennae of both sexes. Recombinant HparOBP3 exhibited distinct binding affinities towards 22 compounds released by organic fertilizers. After 48 h of RNA interference (RNAi), the expression of  HparOBP3  in male and female antennae was decreased by 90.77 % and 82.30 %, respectively. In addition, silencing of  HparOBP3  significantly reduced the electrophysiological responses and tropism of males to  cis -3-hexen-1-ol, 1-hexanol, and (Z)- β -ocimene as well as females to  cis -3-hexen-1-ol, 1-hexanol, benzaldehyde, and (Z)- β -ocimene. Molecular docking indicated that hydrophobic residues Leu-83, Leu-87, Phe-108, and Ile-120 of HparOBP3 were important amino acids for interacting with ligands. Mutation of the key residue, Leu-83, significantly diminished the binding ability of HparOBP3. Furthermore, acrylic plastic arena bioassays showed that the attraction and oviposition indexes of organic fertilizers to  H. parallela  were reduced by 55.78 % and 60.11 %, respectively, after silencing  HparOBP3 . These results suggest that HparOBP3 is essential in mediating the oviposition behavior of  H. parallela .

International Journal of Biological Macromolecules,IF=8.2

https://pubmed.ncbi.nlm.nih.gov/37148950/