Líffræðifélag Íslands - biologia.is
Líffræðiráðstefnan 2021

Erindi/veggspjald / Talk/poster E66

A comparison of the genomes of Icelandic Renibacterium salmoninarum strains to genomes of North American and European strains

Höfundar / Authors: Birkir Þór Bragason (1), Sigríður Hjartardóttir (1), Snorri Már Stefánsson (1), Sigríður Guðmundsdóttir (1), Árni Kristmundsson (1)

Starfsvettvangur / Affiliations: 1. Keldur Institute for Experimental Pathology, Reykjavik, Iceland

Kynnir / Presenter: Birkir Þór Bragason

Studies have shown that the causative agent of bacterial kidney disease (BKD), the Gram-positive bacteria Renibacterium salmoninarum (Rs), is endemic in wild salmonids that inhabit Icelandic freshwater systems, i.e. Arctic char (Salvelinus alpinus), brown trout (Salmo trutta) and Atlantic salmon (Salmo salar). Despite the prevalence of Rs in the wild, macroscopic pathological signs of BKD have not been observed in wild salmonids since regular monitoring started in 1986 and it has been suggested that Rs has been endemic in the Icelandic populations for a long time. The first case of BKD in Iceland was reported in 1968 in association with fish farming and the disease has since then occurred on a regular basis on fish farms in Iceland. This has been associated with the introduction of Rs into the farms via intake of freshwater from local water systems or contact with wild fish. The aim of this study was to gain insight into the genome of Icelandic Rs strains and their relationship to Rs genomes of strains that have been isolated in North America and Europe. Whole genome sequencing was performed on DNA isolated from Icelandic Rs strains isolated from BKD affected rainbow trout, Atlantic salmon, and arctic char that are stored in the sample bank of Keldur. Raw whole genome sequencing data for Rs strains from Europe and North America was obtained from the European Nucleotide Archive. The sequencing data were analysed by alignment to the reference strain, ATCC33209, as well as by de novo genome assembly. Tree construction based on data obtained from both analysis methods suggest that the Icelandic Rs strains form a lineage that is distinct compared to the two Rs lineages previously described in the literature by Brynildsrud et al.