病原感染导致的大规模死亡事件给贝类养殖业带来严重经济损失。研究结果提示I84家族蛋白酶抑制因子在贝类抗感染中发挥重要作用，目前该家族基因在病原入侵中的表达响应及调控机理研究比较匮乏。我们初步研究发现缢蛏I84家族基因存在多个成员，且在基因组中成簇分布，基因间可能已产生分化。本项目以缢蛏为研究对象，拟开展I84家族蛋白酶抑制因子的病原应对反应及转录调控机理研究。首先，开展缢蛏基因组中全部I84家族基因结构、家族进化以及在病原入侵过程中的表达响应的系统分析。其次，筛查相关转录因子，研究响应基因在应对病原入侵时的表达调控机理。最后，鉴定响应基因序列中，特别是转录调控区与缢蛏抗性表型关联的多态性位点，为开发抗病选育标记奠定基础。本项目的顺利实施不但有助于更加全面深入地认识I84家族在贝类免疫中的功能与作用机理，而且对通过选育缢蛏抗病品系来解决养殖中的大规模死亡问题提供重要依据。

Mass mortality caused by pathogen infection lead to serious economic losses of mollusk aquaculture. Previous studies suggested that the I84 family protease inhibitors play an important role in the anti-pathogenic response of mollusks. Whereas there is a lack of information on the gene expression response and regulatory mechanism of this family gene in pathogen invasion. Our preliminary result shown that there are several members of the I84 family gene which distributed in clusters in the Chinese razor clam (Sinonovacula constricta) genome, and they may be differentiated. In the present project, we plan to study the response and expression regulation mechanism of I84 family protease inhibitors in response to pathogen invasion in the S.constricta. Firstly, we will analyze the gene structure, genomic distribution and molecular evolution of all members of the I84 family genes, the gene expression response of I84 family genes under pathogenic stress will be tested. Secondly, the transcription factors as well as regulation mechanism of their expression activity will be clarified. Finally, the functional polymorphic sites in the I84 family gene sequence, especially the transcriptional regulatory regions, which is associated with individual resistance phenotype will be screened and verified. The result of this project will not only contribute to all-round and in-depth understanding of the function and mechanism of the I84 family gene in mollusk immunity, but also provides an important basis for solving the mass mortality issues of the S. constricta.by selective breeding for disease-resistant strains.