Citrobacter freundii is one of the important bacterial diseases responsible for disease outbreaks to wild and cultured fishes globally. However, no known empirical research has focused on exploring relationships between immune response after C. freundii infection in sturgeons. In this study, C. freundii was isolated and identified from artificially breeding Chinese sturgeon, and global measurement of transcriptome response to C. freundii infection in head-kidney and spleen of A. sinensis were conducted to the acknowledgement of the potential mechanisms of pathogen-host interaction triggered by the bacterial infection. In total, differentially expressed genes which significantly associated with immune responses were found to be participated in antigen processing and presentation (MHC I, MHC II, HspA1, Hsp90A, Hsp70, CTSL, and CTSE), and acute phase response (serotransferrin and CP), as well as changing of other immune-related cytokine, such as chemokine and interferon, which proving their reacting and regulatory role during the response of thehost against C. freundii infection in fish. C. freundii can cause serious disease in sturgeon species was first reported in this study, and innate immune responses to C. freundii infection in this study will be conducive to understand the defense mechanisms and making appropriate prevention strategies in A. sinensis aquaculture operations.

弗氏柠檬酸杆菌是导致全球野生和养殖鱼类疾病暴发的重要细菌性疾病之一。然而，没有已知的实证研究集中于探索鲟鱼感染弗氏梭菌后免疫反应之间的关系。本研究从人工养殖中华鲟中分离鉴定出C. freundii ，并对中华鲟头肾和脾脏中C. freundii感染的转录组反应进行全局测量进行以确认由细菌感染引发的病原体 - 宿主相互作用的潜在机制。总体而言，发现与免疫反应显着相关的差异表达基因参与抗原加工和呈递（MHC I、MHC II、HspA1、Hsp90A、Hsp70、CTSL 和 CTSE）和急性期反应（血清转铁蛋白和 CP）以及其他与免疫相关的细胞因子，如趋化因子和干扰素的变化，证明了它们在宿主对鱼类弗氏梭菌感染的反应过程中的反应和调节作用。本研究首次报道了C. freundii可引起鲟鱼物种的严重疾病，对C. freundii的先天免疫反应本研究中的感染将有助于了解中华鳖水产养殖作业中的防御机制并制定适当的预防策略。