Symbiosis-driven nutrient transporters: Central to tsetse fly biology

About This Grant

Project summary Tsetse flies (Diptera: Glossinidae) are the cyclical vectors of African trypanosomes (Trypanosoma brucei spp.) which are the causative agents of fatal Human African Trypanosomiasis (HAT) and Animal African Trypanosomiasis (AAT). Through nutritional supplementation, the obligate bacterial mutualist Wigglesworthia glossinidia enables tsetse to exist exclusively on vertebrate blood and thereby transmit trypanosomes. To fuel dietary provisioning, the largely auxotrophic Wigglesworthia must receive amino acids from the tsetse host. Transport proteins are fundamental to the movement of metabolites into and out of cells, particularly at the host- endosymbiont interface. Here, we aim to characterize the significance of tsetse-generated SLC36 transporters towards facilitating the movement of amino acids (especially proline-the main energy source of tsetse) to Wigglesworthia. Our preliminary data indicates transcript enrichment of two SLC36 transporters (GMOY012047 and GMOY000882) within bacteriomes (tsetse organs that exclusively harbor Wigglesworthia) and the effectiveness of RNAi towards the sustained knockdown of SLC36 transporter expression. The effects of disrupting SLC36 transporter expression using RNAi towards tsetse fecundity, symbiont density, and trypanosome infections will be assessed. Following the comparative analyses of these SLC36 transporters, one will be selected for further characterization of binding substrate specificity using heterologous expression in Xenopus laevis, coupled with radiolabeled amino acids to track cellular intake. The spatial localization and protein quantification of this SLC36 transporter within bacteriomes during tsetse development and reproduction will also be determined using immunohistochemistry. Enhancing our understanding of the role transporters play in the nutritional exchange between tsetse flies and their microbiota, and how this impacts vector biology, could lead to new targets for control measures. These targets could disrupt the symbioses that are essential for the host’s ecological survival.