病害频发和良种匮乏问题已成为制约我国鱼类养殖业进一步健康可持续发展的瓶颈因子。抗病力是养殖鱼类的一个重要经济性状，培育和创制具有优异抗病性状的鱼类品种是当前迫切需要解决的难题。遗传改良是提升养殖鱼类产量和品质的重要手段，但其潜力的发挥受到了常规育种技术的严重制约。鱼类抗病分子机理的解析是进行抗病新品种培育的重要保证，而抗病相关功能基因和分子标记的发掘又是进行抗病分子机理解析的重要基础。鉴于此，本项目拟在已完成的牙鲆全基因组测序的基础上，鉴定出抗牙鲆主要细菌病相关主效功能基因，筛选抗病相关分子标记，构建抗病基因调控网络，揭示牙鲆抗病的分子机理；进而利用目前已经建立的牙鲆家系和群体，进行全基因组重测序，筛选抗病相关SNP位点，进行全基因组关联分析（GWAS），创建牙鲆全基因组选择育种技术，实现鱼类育种由传统技术向基因组选择育种技术的转变，为鱼类抗病新品种培育提供理论基础和技术支撑。

Abstract: The problems of disease occurrence and breed lack are main limiting factors for sustainable and healthy development of aquaculture in our country. Disease resistance is an important trait in farmed fishes, and the urgent problems to solve at the moment are to create and breed the fish species with excellent disease resistances. Genetic improvement is the important way to improve yield and quality of farmed fish, but the potential of which is seriously constrained by traditional breeding technique. Research on molecular mechanism of disease resistance in fish is an important guarantee of new variety breeding. And finding of disease resistance-related functional genes and molecular markers is an important foundation of researching on molecular mechanism of disease resistance. In view of above, based on the availability of whole genome sequences in flounder (Paralichthys olivaceus), the present project focuses on identification the main functional genes resistant to main bacterial pathogens; screening the disease resistance-related molecular markers; determining disease-resistant gene regulatory networks; and revealing the molecular mechanisms of disease resistance in Japanese flounder. And then, we will carry out whole genome re-sequencing for the produced families and population to screen disease resistance-related SNP loci, and implement genome wide association study (GWAS); develop genomic selection (GS) breeding technology for flounder; realize the transfer of fish breeding technology from traditional breeding to genomic selection, and provide a theoretical basis and technical support for breeding new stock with enhanced disease resistant in fish.

病害频发和良种匮乏问题已成为制约我国鱼类养殖业进一步健康可持续发展的瓶颈因子。抗病力是养殖鱼类的一个重要经济性状，培育和创制具有优异抗病性状的鱼类品种是当前迫切需要解决的难题。本项目完成了牙鲆全基因组精细图谱绘制，确定牙鲆基因组为640M，注释功能基因21787个。揭示了牙鲆体色等左右不对称发育的分子机制。构建了牙鲆高密度SNP 遗传连锁图谱，图谱总长度3497.29 cM，标记间隔平均为0.47 cM，将12712个SNP标记定位到24个连锁群上，定位到9个抗鳗弧菌病相关的QTL位点。克隆了牙鲆精氨酸酶II、牙鲆补体样分子3、牙鲆趋化因子受体CCR6A和CCR6B基因，并开展了迟缓爱德华氏菌/鳗弧菌感染后的表达模式分析及重组表达蛋白的抑菌实验分析，揭示出这些基因在抵抗细菌感染过程的重要作用。利用iTRAQ蛋白组学技术，对迟缓爱德华氏菌感染前后的差异蛋白质进行了全面的比较和分析。细菌感染前后的差异蛋白数为206个，包括91个上调蛋白和115个下调蛋白。KEGG通路富集分析发现，差异表达蛋白富集到20条信号通路中，其中以代谢通路、细菌感染、补体级联反应通路最为显著。建立牙鲆家系106个并进行了抗迟缓爱德华氏菌感染试验，对牙鲆抗迟缓爱德华氏菌病家系、不抗病家系、快速生长家系和慢速生长家系等进行了全基因组重测序，筛选出39万多个SNP位点进行遗传效应分析，计算了个体的基因组育种值，建立了牙鲆全基因组选择技术，采用该技术培育出抗病新品种“鲆优2号”牙鲆，并获得新品种证书。在相同养殖条件下，鲆优2号与普通牙鲆相比，养殖存活率和日增重提高20%左右。本项目发表研究论文13篇，其中在Nature Genetics、DNA Research等杂志发表SCI文章11篇，申请国家发明专利1项。本项目成功建立了基因组选择技术并培育出牙鲆抗病新品种，将鲆鲽鱼类抗病育种研究提升至国际领先水平。