EXPRESSION PROFILE ANALYSIS OF ODORANT RECEPTOR GENES IN THE LARVAE OF SAVANNA TSETSE FLY GLOSSINA MORSITANS MORSITANS
Olfaction is important for guiding critical behavioural and survival functions including those involved in regulation and reproduction. Insect odorant receptors (ORs) operate in the first phase of the olfactory system and serving the essential role of conveying chemical signals from volatile odor molecules to the Olfactory Receptor Neurons (ORNs) to evoke a behavioural response. Glossina morsitans morsitans are vectors of trypanosomiasis that causes widespread economic losses in the sub-Saharan Africa by infecting millions of livestock and people with African trypanosomiasis thereby reducing their productivity. So far, very little is available on odorant receptor genes in the larvae and pupae of G. m. morsitans because they have not been broadly profiled to understand the basis of molecular olfaction in such critical developmental stage. For an in-depth understanding of chemoreception in Glossina, we used real-time quantitative (qPCR) analysis to examine the expression profile of OR genes in larvae and pupae of Glossina morsitans morsitans. Our bioinformatics analysed data on the G. m. morsitans OR genes confirms the hypothesis that these genes code for transmembrane domains and that, despite being diverse in sequence, these OR genes form an important component involved in odor binding. The reduced number of expressed OR genes in both larvae and pupae could be due to the fact these two developmental stages are mostly restricted to smaller areas, unlike the adults who explore diverse environments. Further, there is a possibility that a few highly expressed genes in these two stages are involved in a myriad of crucial larval-specific behaviours.