MolStressH2O · Molecular mechanisms and consequences of thermal stress rippling through changing aquatic environments

Heat stress is a driver of current mass mortalities related to anthropogenic global warming. However, current approaches to study heat stress have not considered three major but little known aspects. These are (i) the ripple effect, which could amplify negative outcomes through propagating heat stress among organisms, (ii) heat stress as an evolutionary mutagen and (iii) genomic networks as filters for prezygotic selection, which together could speed up the process of evolutionary adaptation to rapidly changing environments. In this project, these properties of heat stress will be studied in vulnerable early life stages of three distinct aquatic ectotherms (a ragworm, a fish and a frog), to achieve an understanding of how universal these aspects of heat stress are among distinct, unrelated species. First this project will explore whether thermal stress can be propagated by means of chemical communication (stress metabolites) to naive receivers of different species. Outcomes on development will be compared with differential gene expression. We will then identify heat-induced stress metabolites and their molecular pathways of action, through RNAsequencing, Metabolomics and CRISPR-mediated gene editing. We will then test whether thermal stress and stress metabolites exposure induce higher mutation rates, through heat-induced transposon activity and reduced DNA repair capacity. gDNA sequencing will be combined with optical genome mapping to identify mutation rates and new structural variants. Lastly, we will identify the role of functional genomic network constraint in filtering such variants. We will sequence a reference genome, and explore through AI-led simulations whether networks with topological node constraints outperform those without constraint. Together, these objectives will transform our understanding of the mechanisms, and the extent to which organisms will respond to anthropogenic warming.