The overall goal of this study is to provide information on molecular processes in tsetse vectors that mediate their olfactory processes, enabling them to locate their hosts and other critical resources for their survival and reproduction. The goals will be achieved by prospecting for and validating olfaction responsive genes in selected tsetse species (Glossina pallidipes, Glossina austeni and Glossina fuscipes fuscipes) of medical and veterinary importance in Kenya. We propose an integrated and interdisciplinary approach to: 1) Determine differences in olfactory responsive genes in sympatric Glossina pallidipes and Glossina austeni in Shimba hills and Glossina fuscipes fuscipes in Mbita in Kenya and 2) Determine functional roles of olfactory responsive genes in sympatric G. pallidipes and G. austeni in Shimba hills and G. f. fuscipes in Mbita districts in Kenya. We hypothesize that putative olfactory genes among these flies are orthologuous, differentially expressed and significantly influence responses of the flies to different odors. Adults of the selected tsetse species will be sampled from respective sites and RNA will be extracted from head tissues. We will undertake a discovery project by using next generation sequencing technologies to determine global transcriptome-level heterogeneities exhibited between the different species. The DNA obtained from the gut contents of flies will be subjected to PCR amplification with COI marker to determine the putative host species from Barcode of Life Data systems (BOLD) database. Following the comparative transcriptome analysis from the different species we will in vitro validate the presence and expression profiles of select set of putative olfaction related genes through qPCR. The functional role(s) of selected putative olfaction genes will be further investigated through RNAi gene silencing methodologies in conjunction with electro-antennogram and Wind-Tunnel techniques to establish the roles of these genes in modulating the physiology and behavior of the flies. Availability of comprehensive information on olfaction related genes, and their respective functional roles in modulating tsetse olfactory behavior will facilitate further R&D to exploit these genes to control tsetse fly vectors. This research will be done primarily in Kenya at International Centre of Insect Physiology Ecology and Kenya Agricultural Research Institute - Trypanosomiasis Research Center in collaboration with Paul Mireji with companion grant being Global Infectious Diseases (GID) D43 TW007391 (08/01/2008- 03/31/2013).
Human sleeping sickness transmitted by tsetse is a fatal disease in sub-Sahara. In the absence of good vaccines and drugs, vector control can be an effective disease control strategy. Studies proposed here will investigate the molecular aspects of tsetse's olfactory biology from three species resident in Kenya and have the potential to improve the efficacy of existing traps/targets or generate new methods.
|International Glossina Genome Initiative (2014) Genome sequence of the tsetse fly (Glossina morsitans): vector of African trypanosomiasis. Science 344:380-6|