Resistance to a Rhabdovirus (VHSV) in Rainbow Trout: Identification of a Major QTL Related to Innate Mechanisms

Abstract

Health control is a major issue in animal breeding and a better knowledge of the genetic bases of resistance to diseases is needed in farm animals including fish. The detection of quantitative trait loci (QTL) will help uncovering the genetic architecture of important traits and understanding the mechanisms involved in resistance to pathogens. We report here the detection of QTL for resistance to Viral Haemorrhagic Septicaemia Virus (VHSV), a major threat for European aquaculture industry. Two induced mitogynogenetic doubled haploid F2 rainbow trout (Oncorhynchus mykiss) families were used. These families combined the genome of susceptible and resistant F0 breeders and contained only fully homozygous individuals. For phenotyping, fish survival after an immersion challenge with the virus was recorded, as well as in vitro virus replication on fin explants. A bidirectional selective genotyping strategy identified seven QTL associated to survival. One of those QTL was significant at the genome-wide level and largely explained both survival and viral replication in fin explants in the different families of the design (up to 65% and 49% of phenotypic variance explained respectively). These results evidence the key role of innate defence in resistance to the virus and pave the way for the identification of the gene(s) responsible for resistance. The identification of a major QTL also opens appealing perspectives for selective breeding of fish with improved resistance.

Assessment of Genetic Correlation between Bacterial Cold Water Disease Resistance and Spleen Index in a Domesticated Population of Rainbow Trout: Identification of QTL on Chromosome Omy19

“…Recently, a number of major QTL influencing resistance to viral and parasitic diseases in rainbow trout and Atlantic salmon have been identified [55], [56], [57], [58], [59], [60] that may lead to specific selection markers. Identification of a more specific marker associated with BCWD disease resistance on Omy19 would add to this growing list and may have future utility to exploit both between- and within-family selection in aquaculture selective breeding.…”

Infectious disease, shifting climates, and opportunistic predators: cumulative factors potentially impacting wild salmon declines

“…A dQTL study on VHS also identified a single dominant QTL conferring resistance in Rainbow Trout (Verrier et al. ). A subsequent study found no genetic correlation of this QTL with resistance to another fish rhabdovirus, IHNV (Verrier et al.…”

Viral encephalopathy and retinopathy in aquaculture: a review

“…QTLs for resistance to other viral diseases in Salmonids include QTLs for IHNV resistance (Palti, Parsons & Thorgaard 1999;Palti et al 2001;Miller et al 2004;Rodriguez et al 2004;Barroso et al 2008), ISAV resistance (Moen et al 2004(Moen et al , 2007, VHSV resistance (Verrier et al 2013) and salmonid alphavirus (SAV) resistance (Gonen et al 2015). Like for IPNV, the IHNV QTLs explained a high part of the phenotypic variance (up to 32.5% according to Barroso et al 2008), while it was more limited for the ISAV QTL (6% of the phenotypic variance, Moen et al 2007).…”