长江口沿岸核残迹纲纤毛虫原生动物的分类学研究

The class Karyorelictea Corliss, 1974 is widely believed to represent the nature of the ancestral ciliate lineage. International research on morphology and taxonomy of karyorelicteans has been neglected for a long time due to a methodological problem: this group is uncultivable and too fragile to be fixed and stained. However, due to their “primitive” evolutionary status, and key role in the microbial food web in intertidal zone, karyorelicteans are becoming the new hotspots in the research field of genetics, cell biology and phylogeny. I have carried out taxonomy studies on karyorelicteans along Shandong coasts, Yellow Sea, and published more than ten papers. But the research along the coasts of East China Sea is very rare. This work will focus on taxonomy of karyorelictean ciliates collected from intertidal zone, wetland and freshwater near the Yangtze River Estuary, East China Sea by using live observation, silver staining methods, electron microscope, as well as DNA extraction and sequencing. Our aim is to re-build the taxonomic system, clean up chaos from former studies, redescribe or describe poorly known or unknown species and create the first basic file data on biodiversity of karyorelicteans in this area based on morphology, ultrastructure of certain organelles and molecular information. This project will enrich our knowledge of ciliated protozoa and GenBank database, contribute to species diversity in this area, and provide important material for the ecological studies on benthic protozoa.

核残迹纲是纤毛门内最原始的类群，因其培养、固定和染色极为困难，导致全球范围内的研究严重滞后。而由于其特殊的准二倍体大核及专性的砂隙生活方式而成为遗传学、细胞学及水体生态学研究的新热点。作者近年来初步开展了黄渤海沿岸该类群的分类学研究并以首作者身份在国际主流刊物上发表了十余篇论文，但国内迄今在长江口沿岸各生境内的研究则几乎空白。本课题拟以具有重要水文、生境代表性的长江口及周边沿岸为采样地，运用经典和分子技术对该类群展开以分类学为核心的研究，清理历史遗留的错误和混乱，发现并报道新阶元；同时，基于显微和超微结构特征及标记基因的序列信息开展对其分类系统的构建，从而建立我国首份长江口地区核残迹类的物种多样性与系统学的本底资料。本工作将是对全球海洋纤毛虫资源库和基因库的重要补充，同时也为长江口沿岸生物多样性评估及底栖原生动物生态学研究提供第一手的参考资料。

针对长江口沿岸的各类生境开展了纤毛虫采集，并利用现代分类学技术对所获种类进行形态分类学研究。3年来共采集并鉴定40余种纤毛虫。成果主要包括：1）报道了核残迹纲裸咽科的2个新种，并对两个国内新纪录种和5个罕见种进行了重描述；2）对核残迹纲纤毛虫各级阶元的形态学及分子系统学研究进展进行了梳理和归纳；3）建立了长江口崇明岛湿地优势纤毛虫种名录；4）对完成鉴定的40余种纤毛虫进行了DNA提取，向GenBank提交6条SSU rRNA基因序列，并基于分子系统树对系统地位存疑阶元给予新定义，并探讨了各阶元系统进化关系；5）利用透射电镜术和拉曼光谱等方法对核残迹纲喙纤虫属的米勒氏体进行了超微结构及成分研究，首次在纳米级水平揭示了其米勒氏体硫酸钡的晶体结构；6）对长江口崇明东滩湿地底栖纤毛虫群落组成及多样性的驱动因子进行了研究，并发现其功能多样性与氨氮、总氮等环境因子显著相关，可用于指示富营养等环境胁迫；7）本工作已发表7篇SCI收录论文，含两篇一区和两篇二区文章。本研究为长江口物种资源调查、生物多样性保护及环境生物指示提供了档案性资料。