Identification of Stress Sensitive Genes in Hyperthermic Atlantic Salmon (Salmo salar) Embryos by RAP-PCR

Abstract

Deformities of skeletal structures, the heart, and other organs are a recurrent problem in species used in intensive aquaculture. Elevated egg incubation temperature appears to be a high risk factor in the development of these malformations, but the causal relation has not been established. Our aim was to identify candidate genes involved in the development of heat induced deformities in Atlantic salmon (Salmo salar). Temperature sensitive genes were isolated by RNA Arbitrarily Primed (RAP)-PCR. A total of 33 RAP-PCR products were successfully sequenced, and the expression of eight identified genes was further examined by RT-PCR from pooled samples of heat exposed embryos. Five of these genes were demonstrated to be temperature sensitive, of which four were shown to be up-regulated and one was downregulated at elevated water temperatures. The atrial natriuretic peptide (ANP) gene, which is a promising candidate for heart deformities, showed the highest level of heat induction. Three additional RAP-PCR products identified as heterogeneous nuclear ribonucleprotein (hnRNP) A0, acyl CoA binding protein (ACBP) and mitochondrial (mt)-HSP70 showed up-regulated mRNA expression in response to elevated water temperature. The single down-regulated gene was identified as an Atlantic salmon (Salmo salar) homolog of the cysteine and tyrosine-rich 1 (CYYR1) gene. This study demonstrated that a temperature elevation of only 4°C during the early stages of the organogenesis in Atlantic salmon induce altered expression of a number of genes, which are candidates for the development of heat induced deformities.

The effect of ploidy and incubation temperature on survival and the prevalence of aplasia of the septum transversum in Atlantic salmon, Salmo salar L

“…Previously, increased incubation temperature has been shown to increase the incidence of aplasia of the septum transversum in Atlantic salmon (0–4% and 35–60% after incubation at 8 and 14 °C, respectively; Ørnsrud et al . ), and the factors related to this condition include atrial natriuretic peptide (ANP), heat shock protein 70 (Hsp70) and caspase‐6 (Takle, Baeverfjord & Andersen ; Takle et al . ; Takle, Baeverfjord, Helland, Kjorsvik & Andersen ; Takle, McLeod & Andersen ).…”

Parental identity influences progeny responses to incubation thermal stress in sockeye salmonOnchorhynchus nerka

“…While the mechanisms of this delayed mortality are unclear, they could be a result of thermal alterations to genetic or biochemical pathways (e.g. transcriptional networks, extracellular signalling molecules and expression of stress-sensitive genes) during the critical embryogenesis stages (Takle et al, 2004;Johnston, 2006). Latent temperature effects on alevin survival were experienced to varying magnitudes for different offspring families.…”

Developmental temperature stress and parental identity shape offspring burst swimming performance in sockeye salmon (Oncorhynchus nerka)

“…These temperature effects can remain imprinted in later juvenile stages and result in decreased swim performance (Koumoundouros et al 2009). At developmental temperatures that approach upper tolerance limits, thermal stress can result in the disturbance of cellular ⁄ genetic pathways with potential consequences for offspring morphology, physiology and behaviour (Takle et al 2004;Wargelius et al 2005;Turner et al 2007). Whereas thermal stress during development is shown to have latent effects on locomotor performance in herpetofaunal studies (Brana & Ji 2000), similar experiments examining the latent impacts of supra-optimal embryonic temperatures in fish populations have not been conducted.…”