A Novel Marine Pathogen Isolated from Wild Cunners (Tautogolabrus adspersus): Comparative Genomics and Transcriptome Profiling of Pseudomonas sp. Strain J380

Cunner (Tautogolabrus adspersus) is a cleaner fish utilized in the north Atlantic salmon (Salmo salar) aquaculture to biocontrol sea lice infestations. However, bacterial diseases due to native infections in cunner have not been described to date. This study reports the isolation of Pseudomonas sp. J380 from infected wild cunners and its transcriptomic characterization. Transcriptome profiling under iron-limited vs. iron-enriched conditions identified 1,159 differentially expressed genes (DEGs). Cellular metabolic processes, such as ribosomal and energy production, and protein synthesis, were impeded by iron-limitation. In contrast, genes involved in environmental adaptation mechanisms including two-component systems, histidine catabolism, and redox balance were transcriptionally up-regulated. Furthermore, iron-limitation triggered the differential expression of genes encoding proteins associated with iron homeostasis. A