Potential Response to Selection of HSP70 as a Component of Innate Immunity in the Abalone Haliotis rufescens

Abstract

Assessing components of the immune system may reflect disease resistance. In some invertebrates, heat shock proteins (HSPs) are immune effectors and have been described as potent activators of the innate immune response. Several diseases have become a threat to abalone farming worldwide; therefore, increasing disease resistance is considered to be a long-term goal for breeding programs. A trait will respond to selection only if it is determined partially by additive genetic variation. The aim of this study was to estimate the heritability (h 2) and the additive genetic coefficient of variation (CV A) of HSP70 as a component of innate immunity of the abalone Haliotis rufescens, in order to assess its potential response to selection. These genetic components were estimated for the variations in the intracellular (in haemocytes) and extracellular (serum) protein levels of HSP70 in response to an immunostimulant agent in 60 full-sib families of H. rufescens. Levels of HSP70 were measured twice in the same individuals, first when they were young and again when they were pre-harvest adults, to estimate the repeatability (R), the h 2 and the potential response to selection of these traits at these life stages. High HSP70 levels were observed in abalones subjected to immunostimulation in both the intracellular and extracellular haemolymph fractions. This is the first time that changes in serum levels of HSP70 have been reported in response to an immune challenge in molluscs. HSP70 levels in both fractions and at both ages showed low h 2 and R, with values that were not significantly different from zero. However, HSP70 induced levels had a CV A of 13.3–16.2% in young adults and of 2.7–8.1% in pre-harvest adults. Thus, despite its low h 2, HSP70 synthesis in response to an immune challenge in red abalone has the potential to evolve through selection because of its large phenotypic variation and the presence of additive genetic variance, especially in young animals.

Expression of Heat Shock Proteins in Thermally Challenged Pacific Abalone Haliotis discus hannai

“…Previously in Pacific abalone, the gene expression of HSP70 and HSP40 was reported to vary among thermal-sensitive and thermal-tolerant abalones, and the thermal-tolerant line showed higher expression levels than the thermal-sensitive lines [13]. In Haliotis diversicolor, HSP70 was highly expressed in hemocytes under both thermal and pathogen stress due to activation of the immune response [32,33]. Similarly, HSP90 was more sensitive to acute thermal stress then to chronic thermal stress, which was observed in the gill of Haliotis discus [16,17], while HSP70 was observed to be sensitive to acute and chronic thermal stress in Haliotis rufescens [33,34].…”

“…In Haliotis diversicolor, HSP70 was highly expressed in hemocytes under both thermal and pathogen stress due to activation of the immune response [32,33]. Similarly, HSP90 was more sensitive to acute thermal stress then to chronic thermal stress, which was observed in the gill of Haliotis discus [16,17], while HSP70 was observed to be sensitive to acute and chronic thermal stress in Haliotis rufescens [33,34]. Among the sHSPs, HSP20 and HSP26 were significantly expressed in muscle and mantle tissue of H. discus under thermal stress [22,35].…”

Epipodial Tentacle Gene Expression and Predetermined Resilience to Summer Mortality in the Commercially Important Greenlip Abalone, Haliotis laevigata

“…HSP70 has been the focus of many studies involving summer mortality and thermal stress in abalone for several years (Brokordt et al 2015; Cheng et al 2007; Farcy et al 2007; Li et al 2012). Interestingly, the HSP70 identified in this study only demonstrated a preadaptive signature in the resilient Aquaculture abalone.…”

Hsp70 function and polymorphism, its implications for mollusk aquaculture: a review

“…These proteins were first reported by Tissieres et al (1974) who by exposing larvae of Drosophila melanogaster to extreme temperature, observed different proteins in the salivary glands that were not present before the heat treatment. The Hsp's can be synthesized by most of the studied species, such as mammals (Basiricò et al, 2011;Li et al, 2011), insects (Zizzari & Ellers, 2011;Calabria et al, 2012), fish (Hofmann et al, 2000;Narum & Campbell, 2010;Dalvi et al, 2012;Liu et al, 2017), mollusks (Jackson et al, 2011;Zerebecki & Sorte, 2011;Lim et al, 2012;Thompson et al, 2012;Brokordt et al, 2015) echinoderms (Dong et al, 2010) and crustaceans (Ravaux et al, 2007). In all these species groups, the heat-shock response is highly conserved, as is the sequence of the genes that control the mechanism (Kawabe & Yokoyama, 2011;Park et al, 2012;Wojstasik & Wisnik, 2012).…”

“…There are two ways in which the Hsp's can be expressed: 1) constitutively, or 2) induced (Clark et al, 2008;Witt, 2010;Jackson et al, 2011). Hsp's are produced in response to acute cellular stress (Piano et al, 2002;Farcy et al, 2009;Li et al, 2011) produced by external stressors such as drastic temperature changes, amino acid analogues, heavy metals, free radicals, environmental contaminants, immune stimulants agents, inhibitors of metabolic energy and various diseases, among others (Hooper et al, 2012;Wei et al, 2012;Malyshev, 2013;Brokordt et al, 2015;Ravaschiere et al, 2017). Wang et al (2006) observed an increased expression of Hsp70 and Hsp90 in Fenneropenaeus chinensis infected with White Spot Virus (WSSV), compared to healthy individuals, while Wei et al (2012) detected an increased expression of Hsp70 in Miichtys miiuy infected with bacteria of the genus Vibrio.…”