秦岭及周边鱼类寄生三代虫科分类及其寄主特异性的研究

Species of Gyrodactylidae are common viviparous and ectoparasites of teleost fishes worldwide and gyrodactylosis, the disease these parasites cause when intensities are high, have had case histories described from every type of fish culture attempted to date, including anguillids, cyprinids, cichlids, ictalurids, pleuronectids, poeciliids, and salmonids. But it is assumed that only about 2% of species in the family Gyrodactylidae are described. This study will examine the morphology, taxonomy, ecology and molecular sequence to ascertain the species, distribution, the characters of biology and host specificity of the gyrodactylids from the fishes in the Qinling Mountains and its surrounding regions, where is one of the key areas in studying the fauna, genesis and evolution of the organisms. We will compare the differences in the morphology and molecular sequence of the complete mitochondrial genome as well as the ribosomal gene sequence between the gyrodactylids species collected in these areas. Taxonomic study of the gyrodactylids revealed a series of previously undescribed species, and clarified the taxonomy of the other gyrodactylids found using traditional morphology, scanning electron microscopy, mtDNA and rDNA sequence data. We will also reconstruct the Gyrodactylidae phylogeny with the molecular sequence data in the study and downloaded from GenBank by using the software MrBayes 3.1.2, PAUP 4 beta, MEGA 5 and RaxML-7.0.3. Therefore, we can be sure that which molecular sequence data can be use in gyrodactylids taxonomic and systematic study. We will analyse the host specificity dynamics of the gyrodactylids species in the Qinling Mountains as well as estimate the importanc to study the taxonomic and systematic problems in fishes by using their parasites information. This study will be of value to those studying the gyrodactylids fauna in China, culturing fishes in freshwater, and will also help management of natural resources and the protection of the environment in the Qinling Mountain region.

三代虫科是主要寄生于鱼类并引起多种养殖种类疾病的卵胎生体外寄生虫，据估计已知种类仅占2%。本研究用传统形态学结合扫描电镜、系统分类学及分子生物学等方法技术系统研究动植物区系特征、起源和演化的关键地区之一的秦岭及周边地区三代虫科的种类、分布、寄主特异性等特征。通过采用常规三代虫形态学研究方法结合蛋白酶消化、扫描电镜观察等研究，正确确定及归属其种类；测序分析这一区域鱼类寄生三代虫全线粒体基因组及核糖体基因序列的部分基因，结合GenBank已知的数据用相关软件进行部分种类系统发育关系研究，评价各分子标记在分类鉴定中的作用和意义，筛选3-5种可用于种类鉴定的分子标记，为系统研究三代虫打下坚实的基础；在种类及分布研究的基础上，进行寄主特异性分析，结合分布于秦岭南北各水系的寄主和三代虫数据，进行其寄主特异性的应用及评价研究，进一步确定其寄主特异性特征。为理清我国动物区系，保护及利用自然资源服务。

三代虫科是主要寄生于鱼类并引起多种养殖鱼类疾病的卵胎生体外寄生虫，目前已知500多种，科学估计已知种类仅占2%，即此类寄生虫大约有20000种左右。本研究用传统形态学结合扫描电镜、系统分类学及分子生物学等方法技术系统研究了动植物区系特征、起源和演化的关键地区之一的秦岭及周边地区三代虫科的种类、分布、寄主特异性等特征。发现三代虫2属36种，其中1中国新纪录属，10新种，6新纪录种。明确了秦岭及周边地区的三代虫区系，并进行了寄主特异性分析。采用清晰显微形态图像到经蛋白酶消化，扫描电镜观察及记录其骨化结构，加上rDNA内转录间隔区基因序列测序的特征来记述三代虫，使我国三代虫科的研究进入世界先进水平的行列。首次研究报道了拟三代虫属条鳅拟三代虫（Paragyrodactylus variegatus）的全线粒体基因组，在已知少量引物的基础上，新设计特异性引物27条（对），为三代虫的分子系统学研究探明了基本的操作规程和实验规范，可满足三代虫科线粒体基因组研究的需求。在此基础上，完成秦岭及周边19种三代虫线粒体基因组的测序工作。总结了三代虫线粒体基因组的结构特征，评价了各分子标记在分类鉴定中的作用和意义。确定秦岭及周边山区养殖虹鳟寄生三代虫的种类为细鳞鲑三代虫（Gyrodactylus brachymystacis），区别于我国东北等地养殖虹鳟寄生的细鳞鱼三代虫（Gyrodactylus lenoki），明确了其来源、感染途径和季节动态等相关知识，总结了养殖鳟鱼寄生三代虫的生态学规律，为鳟鱼养殖和秦岭山区虹鳟养殖业的健康发展及环境风险评价提供基础知识和理论依据。此项目已发表学术论文21篇，其中SCI论文14篇。培养博士研究生2名，硕士研究生11名。