Zhang Chao, Jones Martin, Govaert Lynn, Viant Mark, De Meester Luc, Stoks Robby
Environmental Research Institute, Shandong University, Qingdao, China.
Evolutionary Stress Ecology and Ecotoxicology, KU Leuven, Leuven, Belgium.
Mol Ecol. 2021 May;30(10):2285-2297. doi: 10.1111/mec.15886. Epub 2021 Mar 26.
Populations rely on already present plastic responses (ancestral plasticity) and evolution (including both evolution of mean trait values, constitutive evolution, and evolution of plasticity) to adapt to novel environmental conditions. Because of the lack of evidence from natural populations, controversy remains regarding the interplay between ancestral plasticity and rapid evolution in driving responses to new stressors. We addressed this topic at the level of the metabolome utilizing a resurrected natural population of the water flea Daphnia magna that underwent a human-caused increase followed by a reduction in predation pressure within ~16 years. Predation risk induced plastic changes in the metabolome which were mainly related to shifts in amino acid and sugar metabolism, suggesting predation risk affected protein and sugar utilization to increase energy supply. Both the constitutive and plastic components of the metabolic profiles showed rapid, probably adaptive evolution whereby ancestral plasticity and evolution contributed nearly equally to the total changes of the metabolomes. The subpopulation that experienced the strongest fish predation pressure and showed the strongest phenotypic response, also showed the strongest metabolomic response to fish kairomones, both in terms of the number of responsive metabolites and in the amplitude of the multivariate metabolomic reaction norm. More importantly, the metabolites with higher ancestral plasticity showed stronger evolution of plasticity when predation pressure increased, while this pattern reversed when predation pressure relaxed. Our results therefore highlight that the evolution in response to a novel pressure in a natural population magnified the metabolomic plasticity to this stressor.
种群依靠已有的可塑性反应（祖传可塑性）和进化（包括平均性状值的进化、组成型进化以及可塑性的进化）来适应新的环境条件。由于缺乏来自自然种群的证据，关于祖传可塑性和快速进化在驱动对新应激源的反应中的相互作用仍存在争议。我们利用水蚤大型溞的一个复活的自然种群，在代谢组水平上探讨了这个问题，该种群在约16年的时间里经历了人为导致的捕食压力增加随后又降低的过程。捕食风险在代谢组中诱导了可塑性变化，这些变化主要与氨基酸和糖代谢的转变有关，这表明捕食风险影响了蛋白质和糖的利用以增加能量供应。代谢谱的组成型和可塑性成分都显示出快速的、可能是适应性的进化，祖传可塑性和进化对代谢组的总体变化贡献几乎相同。在经历最强鱼类捕食压力并表现出最强表型反应的亚种群中，无论是在反应性代谢物的数量还是在多变量代谢组反应规范的幅度方面，对鱼类信息素的代谢组反应也最强。更重要的是，当捕食压力增加时，具有较高祖传可塑性的代谢物表现出更强的可塑性进化，而当捕食压力放松时，这种模式则相反。因此，我们的结果突出表明，自然种群对新压力的进化放大了对该应激源的代谢组可塑性。
