ClimpHIT
Climate change impacts on host-pathogen co-adaptation between freshwater crayfish and the invasive crayfish plague disease agent
Climate change could have contrasting effects on the range expansion of invasive non-native crayfish in Europe and consequently on the crayfish plague disease agent (Aphanomyces astaci). Several genetically distinct strains of A. astaci are nowadays present in Europe, each originally associated with different North American crayfish hosts, which vary widely in their virulence. Pathogen virulence is shaped by natural selection and can shift in response to environmental change, including rising temperatures. Some strains appear better suited to warmer, subtropical conditions, while others perform well in cooler environments, which is most likely due to the geographical origin of their original host as a consequence of host-pathogen coevolution. As climate conditions shift, certain A. astaci strains may become more or less successful, altering the level of threat they pose to native European crayfish and influencing management strategies. On the host side, temperature also affects crayfish physiology more broadly. Warmer water can reduce survival and disrupt metabolic processes, suggesting that heat stress may impair components of the innate immune system. Despite this, controlled studies examining how temperature affects immune function in the noble crayfish (Astacus astacus), an ecologically important native species and one of high value in European aquaculture, are still lacking.
Project aim:
In this project, we analyze in vitro and in vivo the temperature-dependent host-pathogen interactions within the model system of freshwater crayfish (A. astacus) and the invasive crayfish plague agent (A. astaci) under future climate scenarios. The results will advance our knowledge regarding the interface between host-pathogen coevolution and key ecological processes in the face of global environmental change.
We will address this through three successive work packages (WP):
In WP1 we use representative A. astaci strains from our culture collection to determine the impact of temperature on their virulence in vitro. This will allow us to establish the temperature range that maximizes or reduces virulence for each strain.
In WP2, we maintain noble crayfish under various temperature regimes and analyze their resulting immune status. This assessment will involve comparing key physiological parameters, hemocyte counts, and the gene expression of relevant immune system genes.
In WP3, we combine the data generated in WP1 and WP2, which identifies the temperatures inducing maximal pathogen virulence and highest host immune stress, and apply this knowledge in vivo by cross-infection experiments. The outcomes of these controlled challenges will be assessed by recording disease dynamics, pathogen load in the host, and gene expression of selected target genes in both the host and the pathogen.
Funding:
