Transcriptomic Exploration of the Vanessa cardui Immune System
AuthorSelvey, Alexander Drake
AdvisorSmilanich, Angela M
Ecology, Evolution and Conservation Biology
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Vanessa cardui, a polyphagous Nymphalid butterfly known as the painted lady, is an ideal species for understanding ecological interactions influencing immunity, but to date has few molecular resources available to examine the underlying physiological processes driving the regulatory mechanisms of these dynamics. Rapid technological advancements in sequencing technology have decreased sequencing costs to the point of feasibility for studying the molecular basis of ecological models such as V. cardui. To examine gene expression after infection with two unique pathogens, we acquired commercially available V. cardui, infected larvae in the lab with either Escherichia coli or Junonia coenia Densovirus (JcDNV), then sequenced the transcriptome to establish an immune profile for infected larvae and controls. Gene ontology (GO) and differential expression (DE) analyses pointed to an over-representation of genes associated with developmental and energy utilization pathways with no under-representation noted for any pathways after bacterial infection. For viral infection, there was also an over-representation of genes associated with metabolic and energy usage pathways and an under-representation of genes associated with pathways involved in regulatory processes and gene expression. When comparing viral and bacterial infections, there was an over-representation of genes associated with responses to biotic stimulus, defense responses, biosynthetic responses, and movement of cellular components, with an under-representation of genes associated with cellular processes and metabolic processes. Closer investigation revealed preexisting viral populations circulating in the commercially acquires specimens, potentially confounding results based on the proposed research design. However, the tools created from this investigation still hold value for further investigation into the immune response of V. cardui by providing another valuable transcriptomic resource that can be combined with the few existing, non-immune related, resources; making future investigations into any and all molecular functions more powerful and informative. In summary, this transcriptomic investigation pioneers efforts to bring powerful molecular biology tools to address ecological questions of caterpillar immunity.