单细胞真核绿藻在中国绿水螅（Hydra sinensis）体内共生是发育生物学和细胞生物学等领域有较高科研价值的特殊生物学现象。我们在对绿水螅宿主与共生藻相互关系的前期研究中发现，去除共生藻的绿水螅仍能长期存活和繁殖，离体共生藻却失去自由存活能力。这种非对称依赖型共生关系的机理值得深入研究，而水螅与共生藻间的识别特异性、相容、协同、互作、代谢流和基因流等共生策略是其中的重要科学问题。基于此，本课题拟运用系统性的比较转录组学及比较蛋白质组学方法，在中国绿水螅个体水平（中国绿水螅野生型与去除共生藻的绿水螅间）、细胞水平（有绿藻共生的内胚层皮肌细胞与去除共生藻的内胚层皮肌细胞间）及共生藻（在体共生藻与离体共生藻间）三个层次上研究该共生体与共生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，以期对水螅-绿藻共生体中宿主水螅与共生藻间这种特殊共生关系的分子生物学机理进行综合分析和评价。

The symbiotic system of Chinese green hydra (Hydra sinensis) and unicellular eukaryotic green algae is a special biological model which has a high scientific value in the field of developmental biology and cell biology. The results of our former studies about the relationship between green hydra and its symbiotic algae indicated that H. sinensis artificial strain without symbiotic algae still has the ability of long-term survival and reproduction, while the symbiotic algae in vitro lose the ability to survive in the wild. Thus their special asymmetrically dependent symbiotic relationship is worthy of further study and the underlying symbiotic strategies such as recognition, compatibility, coordination, interaction, metabolic flux and gene flow between green hydra and its symbiotic algae are of significant importance to help us understand this special symbiotic relationship. Hence, this project will attempt to study the differently expressed genes and proteins, genetic regulations and metabolic pathways which are related to symbiosis based on the comparative transcriptome and proteome analysis between H. sinensis artificial strain without symbiotic algae and its wild type strain with symbiotic algae, between the gastrodermal myoepithelial cell strain without symbiotic algae and its wild type cell strain with symbiotic algae, as well as between the symbiotic algae in vivo and the symbiotic algae in vitro. The project is valuable for us to better understand the molecular mechanism about the special symbiosis of green hydra.