富营养湖泊中溞属种类表型可塑性的生态适应及其分子进化机制

人类活动加剧导致了湖泊富营养化的加剧，蓝藻水华和渔业养殖影响富营养湖泊中溞属种类表型可塑性的发生。运用转录组测序、荧光定量PCR和分子标记技术，研究长江中下游地区富营养湖泊中溞属种类表型可塑性的生态适应及其分子进化机制。结合湖泊沉积层保存的溞属种类休眠卵，通过揭示历史种群与现代种群的形态、生活史特征及相关候选基因表达的差异，探讨溞属种类响应富营养化进程中形成的表型可塑性的生态适应机制和长期的分子进化规律；通过开展鱼类信息素、藻毒素及其共同作用对溞属种类的形态、生活史特征及相关候选基因表达的影响研究，揭示长江中下游地区富营养湖泊中影响溞属表型可塑性的生态适应及其分子进化机制；通过不同湖泊溞属种类的遗传结构分析，进一步探讨长江中下游地区富营养湖泊中溞属种类的物种多样性和物种形成的可能性。本研究结果将为在湖泊富营养化进程中探讨物种对环境选择的适合度及物种进化规律提供理论依据。

Human activities strengthen the process of lake eutrophication. Cyanobacterial bloom and fishery culture could affect the occurence of phenotypic plasticity of Daphnia species in eutrophic lakes. Using the technology of transcriptome sequencing, real-time fluorescence quantitative PCR and molecular markers (16S DNA，COⅠ and microsatellite), the mechanisms on ecological adaptation and molecular evolution of phenotypic plasticity of Daphnia species in eutrophic lakes located in the middle and lower reaches of the Yangtze River were investigated. Combined with the resting-eggs of Daphnia species stored in lake sediments, we discussed that the ecological adaptation mechanism and long-term molecular evolution laws of the formation of Daphnia phenotypic plasticity in response to the process of lake eutrophication, through revealing the differences of morphology, life history traits and the expression of candidate genes in Daphnia between ancestral populations and modern populations. In order to reveal the mechanisms on ecological adaptation and molecular evolution of phenotypic plasticity of Daphnia species in eutrophic lakes, we studied the effects of fish kairomones, microcystins and their combination on the morphology, life history traits and candidate genes of Daphnia species. We further discussed species diversity of Daphnia and the possibility of speciation according to the analysis on genetic structure of Daphnia in different eutrophic lakes located in the middle and lower reaches of the Yangtze River. Our results will provide the theory evidence to the fitness of species in response to environmental selection and species evolutionary mechanism in the process of lake eutrophication.