Transcriptomic Analysis of Resistance and Virulence in Stickleback Host-Parasite Systems

CLUSTER: „Evolutionary genetics of three-spined stickleback – parasite interactions“

Helmholtz-Zentrum für Ozeanforschung Kiel (GEOMAR)

gemeinsam mit:

Professor Dr. Erich Bornberg-Bauer

How genetic diversity among hosts and parasites is maintained is still largely unresolved. This project focuses on the role of genetic divergence / diversity and its functional genetic basis in host resistance and parasite virulence in stickleback–macroparasite interactions. To address rapid evolvability and specificity in innate immunity, artificial stickleback selection lines towards trematode D. pseudospathaceum infection that were initiated in phase I of this project are sampled immunologically and in terms of gene expression in order to characterize the genetic basis of coevolutionary interactions on the host side. We use state-of-the art, global RNAseq methods that permit to address several important questions beyond the original hypotheses, namely

1. What are relevant defence gene pathways after single, multiple and repeated infections with single /several clones of a trematode parasite, and which inferences can be made for the interaction of innate and adaptive immunity?
2. What are transcriptomic correlates of enhanced/reduced resistance after stickleback artificial selection, including enrichment of particular splice variants and allele specific gene expression?
3. Is the genetic basis of resistance evolution similar or different among fish families?

The second project part integrates with the work proposed by Scharsack/Kalbe/Samonte-Padilla and analyzes the transcriptome data on different populations of a second parasite species, the tapeworm S. solidus that reveal markedly different infectivity and virulence towards stickleback. Important questions are:

1. What are genes underlying infectivity /virulence in Schistocephalus, and what is cross-reactivity with Diplostomum?
2. Are different genes and pathways expressed depending on the origin of hosts?
3. Does S. solidus gene expression depend on environmental stressors such as infections with other parasites and temperature variation. The main goal is to identify the transcriptomic correlates of parasite local adaptation, as one step to characterize the interactome underlying the parasite-fish interaction.