刺参对高温低氧胁迫的行为生理响应与分子调控特征

The sea cucumber Apostichopus japonicus has been exploited as a very important economic species in China. Hyperthermia and hypoxia are the main reasons of sea cucumbers die over large areas every summer, thus leading a necessity to study the response mechanism. We plan to observe the changes of individual’s feeding behavior and population’s movement and breeding behavior towards high temperature, low oxygen as well as the combined treatment. The physiological status, including histological structure, energy budget, enzyme activity will be analyzed at the same time. After developing the gene and microRNA and lncRNA expression profiles, the key genes will be analyzed and validated by several methods, including hybridization, real-time quantitative PCR, immunohistochemical, RNAi and antibody blocking. The whole status will be used to build genetic regulatory network. The thermal tolerant family and the hypoxia tolerant family will be cultured to support the aquaculture model and the risk pre-warning mechanism in order to reduce large scale death in summer. This project is devoted to illustrate the adaptive mechanism and molecular mechanism of the sea cucumber Apostichopus japonicus towards high temperature and low oxygen environment.

刺参是我国重要的海珍品，高温低氧环境是导致夏季自然海区的刺参大面积死亡的主要原因。因此，探究刺参应对高温低氧环境的响应机制十分必要。本项目以刺参为研究物种，对高温、低氧单独胁迫及复合胁迫下的个体摄食行为变化以及群体运动轨迹、运动速度等行为进行观察，同时对刺参组织结构、呼吸频率、能量收支、免疫酶活等生理状态进行分析，构建基因表达谱及microRNA、lncRNA表达谱，筛选出关键基因，应用原位杂交、实时定量、免疫组化等技术手段对关键基因的时空表达进行分析，并采用RNA干扰等技术对关键基因进行功能验证，系统构建逆境下刺参的分子调控通路；探究刺参对逆境（高温、低氧）的生理行为适应机制及分子机理，进而提出高温低氧常态化下减少刺参大面积死亡的风险预警指标及增养殖模式，指导刺参健康度夏。

本研究将刺参作为一种典型的棘皮动物模型，研究其对高温低氧逆境的生理与分子响应机制。研究发现，较单因素胁迫相比，双因素协同作用下刺参的耐受性急剧下降。研究明确了环境胁迫下刺参的分布状态、运动速度、排泄摄食等生理行为发生改变，如低氧胁迫下刺参多集中于水表面分布，机体形态、体壁及内脏状况与正常状态存在差异。刺参组织结构及细胞形态变化证实了高温低氧对刺参组织损伤的影响。揭示了高温低氧环境胁迫下刺参中消化功能可能受到潜在的负面影响，明确了过程中刺参的免疫防御机制被诱导，与NF-κB通路、蛋白酶、补体系统、热休克蛋白家族和转铁蛋白家族有关的免疫因子共同作用防御环境胁迫。综合基因组、转录组及non-coding RNA组等多组学数据，查明了参与刺参高温低氧响应相关调控途径中各关键分子的表达变化规律，明确了“HIF gene—Aja-miR-2013-3p—MSTRG.34610”以及“HIF gene—Aja-miR-2013-3p—MSTRG.10941”的编码与非编码RNA调控通路。构建了刺参应对环境胁迫的应答调控网络，建立了逆境下刺参健康养殖系统。研究表明，刺参在“物质生物合成、运输和代谢”、“信号转导”、“蛋白质合成”、“免疫和防御反应”以及“能量产生和转化”等方面采取不同的策略应对不同的环境胁迫。本研究丰富了刺参对逆境响应的基础生物学理论，为刺参度夏提供理论借鉴与数据支撑，促进了刺参这一重要经济物种的养殖产业可持续发展。同时为研究棘皮动物应对逆境的生存策略及生存机制提供了基础。