基于比较组学探讨全球暖化及光辐射增强叠加胁迫诱发刺胞动物-微藻共生体白化现象的分子机理——以绿水螅为例

受全球暖化及光辐射增强的叠加胁迫，珊瑚礁主成分刺胞动物-微藻共生体白化（共生藻数量减少）日趋严重。热胁迫和强光胁迫破坏宿主与微藻间共生关系稳定性进而诱发白化的机制值得深入研究，而宿主与共生藻间相容、互作及代谢流等共生策略对气候异常的响应是其中重要的科学问题，但珊瑚礁刺胞动物-微藻共生体难以规模化繁殖培养严重制约相关研究的开展。我们筛选到一个“热-强光”双胁迫参数组合能诱导绿水螅白化；胁迫解除后共生藻数量逐渐恢复（去白化），因此绿水螅可作为该类共生体白化现象类比研究的模式生物。基于此，本课题拟运用比较组学方法，分别在热-强光双胁迫、热单胁迫及强光单胁迫背景下对绿水螅宿主和共生藻在白化及去白化进程不同阶段差异表达的基因、蛋白质和代谢物进行系统性比较研究，揭示宿主和共生藻与白化相关的基因及蛋白质、基因表达调控途径及代谢通路的多维特征，以期对刺胞动物-微藻共生体白化发生分子机理进行综合分析和评价。

Under the combined stress of global warming and enhanced light radiation, the bleaching (the number of symbiotic algae decreases) of cnidarian-microalgae symbionts, as the main component of the coral reef ecosystem, is becoming more and more serious. The mechanism by which heat and strong light threaten the stability of this type of symbiont is worthy of further study, and the response of symbiotic strategies such as compatibility, interaction and metabolic flow between host and symbiotic algae to climate anomalies is an important scientific issue. However, one fact restricts seriously the development of related research about coral bleaching that cnidarian-microalgae symbionts from coral reef are difficult to be propagated and cultured on a large scale in the laboratory. In our preliminary study, we screened out a "heat - strong light" combined stress condition which could make green hydra bleach, and the number of symbiotic algae in green hydra gradually recovered (de-bleaching) after the stress was relieved, so green hydra could be used as an alternative model organism for the analogical study about the bleaching of cnidarian-microalgae symbionts. Based on this, this study intends to use transcriptomic, proteomic and metabolomic analysis to compare systematically genes, proteins and metabolites that are differentially expressed between different stages in the process of bleaching and de-bleaching of green hydra under the background of the combined stresses of heat and strong light, the heat stress and the strong-light stress respectively. The multi-dimensional characteristics of genes and proteins related to bleaching, gene expression regulation pathways and metabolic pathways from the project are valuable for us to better understand the molecular mechanisms about the bleaching of cnidarian-microalgae symbionts.