Meeting Abstract
Obligate nutritional endosymbioses represent the most intimate relationship between species. Nutritional endosymbioses are well studied, but we lack a full picture of how two disparate organisms, a bacterial endosymbiont and a eukaryotic host, are integrated. The mTOR pathway is known to integrate nutritional conditions with cell growth and survival. Recent work on amino acid transporters in aphids suggests the mTOR pathway as point of integration between an aphid host and it’s amino acid provisioning endosymbiont Buchnera aphidicola (housed in specialized organs called bacteriomes). The mTOR pathway was previously unstudied in any nutritional endosymbiosis. We annotated the mTOR pathway in two aphid species, Acyrthosiphon pisum and Myzus persicae using BLASTp from Drosophila melanogaster, HMMs, and gene phylogenies. We constructed transcriptomes for bacteriome, gut, and whole insect tissue for three lines of M. persicae and carried out differential expression analysis. Annotation of the mTOR pathway identified some novel duplications in both aphid species. Differential expression analysis showed that genes specific to the amino acid sensitive mTOR Complex 1 were more highly expressed in bacteriomes than genes specific to mTOR Complex 2. In comparison to gut, another nutrient-provisioning tissue, the putative glutamine/arginine sensing transporter SLC38A9 showed 6.5 fold higher bacteriome expression. Characterization and immunolocalization of the SLC38A9 is underway both to confirm orthology, and interrogate its role in a new symbiotic context. This exploratory study suggests that the mTOR pathway may play an important role in mediating the relationship between aphids and their endosymbiont Buchnera. Our work especially highlights the need for more intensive study of the mTOR pathway in nutritional endosymbiosis
