Odorant binding proteins (OBPs) enriched in the sensillum lymph are instrumental in facilitating the transfer of odorous molecules to the responsive receptors. In Orthopteran locust species, an in-depth understanding of this important soluble protein family is still elusive. In a previous study, we have demonstrated that the repertoire of locust OBPs can be divided into four major clades (I–IV) on the phylogenetic scale and for representatives of subfamily I-A and II-A a distinct sensilla-specific expression pattern was determined. In this study, by focusing on a representative locust species, the desert locust Schistocerca gregaria, we have explored the antennal topographic expression for representative OBPs of other subfamilies. First, subtypes of subfamily III-A and III-B were exclusively found in sensilla chaetica. Then, a similar expression pattern in this sensillum type was observed for subfamily I-B subtypes, but with a distinct OBP that was expressed in sensilla coeloconica additionally. Moreover, the atypical OBP subtype from subfamily IV-A was expressed in a subpopulation of sensilla coeloconica. Last, the plus-C type-B OBP subtype from subfamily IV-B seems to be associated with all four antennal sensillum types. These results profile diversified sensilla-specific expression patterns of the desert locust OBPs from different subfamilies and complex co-localization phenotypes of distinct OBP subtypes in defined sensilla, which provide informative clues concerning their possible functional mode as well as a potential interplay among OBP partners within a sensillum.

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