Endosymbiosis is a process whereby one cell takes up stable residence within another cell, occasionally allowing the new consortia to harness previously unexploited resources. For example, plants are able to use the Sun's energy because of an ancient endosymbiosis between a bacterium and a eukaryotic cell. Similarly, many sap-feeding insects-some of which are devastating crop pests-rely on bacterial endosymbionts to survive. Insect endosymbioses are useful models because they are of an intermediate age: old enough to show many parallels to mitochondria and chloroplasts, but recent enough to retain a clear bacterial character. Studying insect-bacterial symbioses thus provide insight into the forces and mechanisms involved in establishing and maintaining bacteria-host relationships. This proposal includes outreach through a children's science program to teach about bacterial symbioses.
Obligate insect endosymbionts have highly reduced genomes that have lost many genes compared to their free-living ancestors. Similar to organelles, some endosymbiont genomes contain fewer genes than thought necessary to support cellular life. This project will use the cicada endosymbiont Hodgkinia as a model to study how symbionts with reduced genomes function with so few genes. The PIs will investigate the structure and function of Hodgkinia-supporting insect tissues using a combination of cutting edge light and electron microscopy, with the aim of better understanding if and/or how insect hosts provide symbionts with essential cellular components. The awardee will answer these questions by labeling cicada proteins and RNAs to localize these gene products within symbiont-harboring tissues. The results of this study are important for understanding host-bacterial interactions, the evolution of organelles, and for improving microscopy methods on insect tissues.
