Antennal Enriched Odorant Binding Proteins Are Required for Odor Communication in Glossina f. fuscipes

Abstract

Olfaction is orchestrated at different stages and involves various proteins at each step. For example, odorant-binding proteins (OBPs) are soluble proteins found in sensillum lymph that might encounter odorants before reaching the odorant receptors. In tsetse flies, the function of OBPs in olfaction is less understood. Here, we investigated the role of OBPs in Glossina fuscipes fuscipes olfaction, the main vector of sleeping sickness, using multidisciplinary approaches. Our tissue expression study demonstrated that GffLush was conserved in legs and antenna in both sexes, whereas GffObp44 and GffObp69 were expressed in the legs but absent in the antenna. GffObp99 was absent in the female antenna but expressed in the male antenna. Short odorant exposure induced a fast alteration in the transcription of OBP genes. Furthermore, we successfully silenced a specific OBP expressed in the antenna via dsRNAi feeding to decipher its function. We found that silencing OBPs that interact with 1-octen-3-ol significantly abolished flies’ attraction to 1-octen-3-ol, a known attractant for tsetse fly. However, OBPs that demonstrated a weak interaction with 1-octen-3-ol did not affect the behavioral response, even though it was successfully silenced. Thus, OBPs’ selective interaction with ligands, their expression in the antenna and their significant impact on behavior when silenced demonstrated their direct involvement in olfaction.

Recent Insights into Insect Olfactory Receptors and Odorant-Binding Proteins

“…Together, these data are consistent with a combination of the carrier and presentation models for OBP function and implicate a direct interaction between the LUSH and Or67d–Orco pheromone receptors on the dendrites. Following these studies, many groups have demonstrated specific roles for OBP members in the detection of volatile ligands in many species [ 79 , 80 , 81 , 82 , 83 , 84 , 85 , 86 , 87 , 88 ], and even for tastants and humidity [ 89 , 90 ]. Finally, in Drosophila , an odorant-binding protein has been implicated in blocking sugar taste detection when sucrose is present with bitter compounds [ 91 ].…”

Identification and characterization of odorant‐binding protein genes in the brown‐winged green bug, Plautia stali

“…The number of OBP genes in the genome ranges from 12 to 109 among insect species (Venthur & Zhou, 2018). Functional analyses demonstrated essential roles of several OBPs in olfaction (Xu et al, 2005; Shiota et al, 2018; Diallo et al, 2021), not only in perception, but also in deactivating or moderating odor stimulations (Scheuermann & Smith, 2019; Rihani et al, 2021). The OBP genes are expressed in various organs, such as the brain, reproductive organs, digestive organs, and muscles.…”

An angiotensin converting enzyme homolog is required for volatile pheromone detection, odorant binding protein secretion and normal courtship behavior in Drosophila melanogaster

“…Exactly how invertebrate OBPs affect odorant responses is not clear, but involves direct interactions between binding proteins and odorants. Defects in pheromone and odorant detection have been observed in many insect species lacking specific OBP ( Pophof 2004 ; Laughlin et al 2008 ; Fawaz et al 2014 ; Dong et al 2017 ; Zhang et al 2017 ; Dong et al 2019 ; Scheuermann and Smith 2019 ; Mozuraitis et al 2020 ; Chen et al 2021 ; Diallo et al 2021 ; Du and Chen 2021 ; Gao et al 2021 ; Guo et al 2021 ; Han W-K et al . 2022 ; Tian et al 2023 ).…”