海洋底栖纤毛虫：基于转录组的水平基因转移现象研究

水平基因转移现象（HGT）是海洋原生生物适应环境及其与细菌互作的重要机制。开展海洋底栖原生生物HGT现象研究，是理解该生态类群适应性进化和生理生化特征的重要途径。迄今，针对海洋底栖原生生物的HGT研究非常有限，尤其是HGT在自由生异养类群中的功能及其分布尚不清楚；究其原因，主要是自由生类群大多不易培养，导致可参考的组学信息极少，限制了相关研究的开展。本项目拟以海洋底栖环境典型异养纤毛虫（线口纲和盔帽纲）为研究对象，通过多种异质性底栖生境样品采集，结合单细胞转录组技术，突破不可培养类群组学数据获取的瓶颈，构建底栖纤毛虫典型类群的转录组参考数据库；通过生物信息学分析和系统进化树构建，对多种复杂底栖生境中纤毛虫的HGT进行挖掘和判定，探讨HGT在不同生境纤毛虫典型类群中的基本功能和分布模式；其中着重关注环境适应和元素代谢相关的HGT，探讨底栖原生生物的适应性进化及其对底栖生态系统物质循环的贡献。

Horizontal gene transfer (HGT, also termed lateral gene transfer) is recognized as important mechanism of bacteria-eukaryote interactions and a major evolutionary force during the adaption of marine protist. A study on the HGT events of benthic protist, is fundamentally important for our deeper understanding of the ecological adaptation and the special physiologies of these key players in the ecosystem. Nowadays, HGT studies in marine benthic protist are rare and restricted on a few saprophytic groups. HGT events and their distributions in the typical heterotrophic free-living protist are still poorly understood, and suffered from a lack of transcriptome data. We propose to do a HGT study in two classes of typical marine benthic ciliates (Litostomatea and Armophorea), using quantity data generated from transcriptome sequencing or single-cell amplification technique. Ciliate cells will be sampled in different marine benthic habitats. Transcriptome will be sampled on genus levels and used to deduce the HGT events. Gene annotation and phylogenic analyses will be carried to gain the main information of the HGT function. The distribution of HGTs specifically related to habitat adaptions and to nutrient metabolism will be examined under class level. Overall, the outcome of this project will offer crucial references to understand the adaptive evolution and the contribution to biogeochemical cycles of the marine benthic protozoa.