Chilean researchers have identified 4,550 transposable elements (TEs) active during Piscirickettsia salmonis infection in Atlantic salmon, with 84% showing increased expression in infected fish.
The study was conducted by researchers from the Universidad de Santiago de Chile, together with specialists from Benchmark Animal Health, IDEVAC, and Caleta Bay. They analysed RNA sequencing data from the anterior kidney of infected fish.
Transposable elements are mobile DNA sequences that can shift position within the genome. In Atlantic salmon, they account for more than half of all genetic material. Until now, most SRS research has focused on classical immune genes such as cytokines and T-cell markers.
The new findings suggest TEs are not passive. Genes associated with the activated elements were linked primarily to metabolic and immunological functions, pointing to a coordinated role in the host response.
“These findings reveal extensive transcriptional activation of transposable elements during bacterial infection in Atlantic salmon and suggest a coordinated dynamic of gene expression and transposable elements as part of the host response,” the authors said.
The researchers acknowledged that correlation-based analysis cannot establish causal regulatory relationships. They described the results as providing “a quantitative framework for investigating mobilome dynamics during host-pathogen interactions in salmonids.”
The study, titled Differential activation and gene-coupled transcriptional dynamics of transposable elements during Piscirickettsiosis in Atlantic salmon, adds a new dimension to SRS research.
