Transcriptomic responses to multigenerational environmental warming in a cold-adapted salmonid usingde novoRNA sequencing

Abstract

AbstractCold-adapted species are particularly threatened by climate change as rates of environmental warming outpace the ability of many populations adapt. Recent evidence suggest that transgenerational thermal plasticity may play a role in the response of cold-adapted organisms to long-term changes in temperature. Using RNA sequencing, we explored differential gene expression of lake trout (Salvelinus namaycush), a cold-adapted species, to examine the molecular processes that respond to elevated temperatures under conditions of within-generation (offspring) and transgenerational (parental) warm-acclimation. We hypothesized that genes associated with metabolism, growth and thermal stress/tolerance would be differentially expressed in juvenile lake trout offspring depending on their own acclimation temperature and that of their parents. We found enriched pathways for thermal stress, signaling processes, immune function, and transcription regulation, although the specific genes and direction of differential expression (up- or downregulation) depended on the combination of offspring and parental thermal rearing conditions. While parental warm-acclimation did have a transgenerational effect on gene expression in their offspring, within-generation warm-acclimation had a larger effect on differential expression, enriching more pathways. We provide evidence of the transgenerational response to warming at the transcriptional level in lake trout, which should be useful for future studies of transcriptomics and plasticity in these and other cold-adapted species.