Wendling Carolin C, Fabritzek Armin G, Wegner K Mathias
Wadden Sea Station Sylt Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research List Germany; GEOMAR, Helmholtz Centre for Ocean Research Kiel Germany.
Department of Ecology Institute of Zoology Johannes Gutenberg-University of Mainz Mainz Germany.
Evol Appl. 2017 Mar 9;10(4):338-347. doi: 10.1111/eva.12452. eCollection 2017 Apr.
The consequences of emerging marine diseases on the evolutionary trajectories of affected host populations in the marine realm are largely unexplored. Evolution in response to natural selection depends on the genetic variation of the traits under selection and the interaction of these traits with the environment (GxE). However, in the case of diseases, pathogen genotypes add another dimension to this interaction. Therefore, the study of disease resistance needs to be extended to the interaction of host genotype, pathogen genotype and environment (GxGxE). In this study, we used a full-sib breeding design crossing two genetically differentiated populations of the Pacific oyster (Thunberg, 1793), to determine the influence of host genotype, pathogen genotype and temperature on disease resistance. Based on a controlled infection experiment on two early life stages, that is, D-larvae and Pediveliger larvae at elevated and ambient water temperatures, we estimated disease resistance to allopatric and sympatric . by measuring survival and growth within and between genetically differentiated oyster populations. In both populations, survival was higher upon infection with sympatric ., indicating that disease resistance has a genetic basis and is dependent on host genotype. In addition, we observed a significant GxGxE effect in D-larvae, where contrary to expectations, disease resistance was higher at warm than at cold temperatures. Using thermal reaction norms, we could further show that disease resistance is an environment dependent trait with high plasticity, which indicates the potential for a fast acclimatization to changing environmental conditions. These population-specific reaction norms disappeared in hybrid crosses between both populations which demonstrates that admixture between genetically differentiated populations can influence GxGxE interactions on larger scales.
新出现的海洋疾病对海洋领域中受影响宿主种群进化轨迹的影响在很大程度上尚未得到探索。对自然选择的进化取决于受选择性状的遗传变异以及这些性状与环境的相互作用（基因与环境互作，GxE）。然而，在疾病的情况下，病原体基因型为这种相互作用增添了另一个维度。因此，抗病性研究需要扩展到宿主基因型、病原体基因型和环境的相互作用（GxGxE）。在本研究中，我们采用全同胞育种设计，使太平洋牡蛎（Thunberg，1793）的两个遗传分化种群进行杂交，以确定宿主基因型、病原体基因型和温度对抗病性的影响。基于对两个早期生命阶段（即D型幼虫和壳顶幼虫）在升高和环境水温下的对照感染实验，我们通过测量遗传分化的牡蛎种群内部和之间的存活和生长情况，估计了对异域和同域病原体的抗病性。在两个种群中，感染同域病原体后的存活率都更高，这表明抗病性具有遗传基础且依赖于宿主基因型。此外，我们在D型幼虫中观察到了显著的GxGxE效应，与预期相反，温暖温度下的抗病性高于寒冷温度下的抗病性。利用热反应规范，我们可以进一步表明抗病性是一种具有高可塑性的环境依赖性状，这表明快速适应不断变化的环境条件具有潜力。这些种群特异性反应规范在两个种群之间的杂交后代中消失了，这表明遗传分化种群之间的混合可以在更大尺度上影响GxGxE相互作用。
