Hirame novirhabdovirus (HIRRV), as a highly pathogenic fish virus, is frequently prevalent in a variety of aquaculture fish in recent years, which seriously threatens the healthy development of aquaculture industry. Epidemiological studies show that the outbreak of HIRRV is obviously temperature dependent. Virus proliferation experiments in vitro and in vivo at different temperatures indicate the antiviral response of flounder is a main reason affect the replication of HIRRV. The RNA-Seq was used to analyze the different antiviral response in flounder which infected with HIRRV at different temperatures, the experiment set two temperatures of 10 °C and 20 °C. The flounder infected with HIRRV by artificial injection, and the spleens were collected at 24 h after infection. Meanwhile, the fish injected with EPC supernatant at different temperatures were set as control groups. It can obtain four pairwise comparison groups if determine a single variable, and the differentially expressed genes were further selected. The results showed that after infection with HIRRV at 10 °C and 20 °C, the differentially expressed genes in spleen were significantly enriched in inflammatory and immune-related pathways like Arachidonic acid metabolism, Cytokine-cytokine receptor interaction, Toll-like receptor (TLR) signaling pathway, RIG-I-like receptor (RLRs) signaling pathway, NOD-like receptor (NLR) signaling pathway and Cytosolic DNA-sensing pathway etc. In addition, the expression of phagocytes, lysosomes, endocytosis related genes were significantly upregulated at high temperature whether HIRRV positive or not. But compared to the infected flounder at 10 °C, some genes of RLRs signaling pathway were significantly upregulated at 20 °C, it can be speculated that RLRs pathway may be related to the anti-HIRRV response of flounder. Therefore, key genes of RLRs signaling pathway including mda5, lgp2, mita, mavs, irf3, irf7, ifn I-3 and ifn-γ were selected, and the temporal expression patterns of these genes in infected flounder at different temperatures were further detected by qRT-PCR. The results showed that HIRRV infection can significantly stimulate and activate the RLRs pathway of flounder, and the response level of this pathway was significantly higher at 20 °C than 10 °C. In general, this study provides important data for the further study about the pathogenesis of HIRRV infection in flounder.

Hirame Novirhabdovirus（HIRRV）作为一种高致病性鱼病毒，近年来在各种水产养殖鱼中普遍流行，严重威胁着水产养殖业的健康发展。流行病学研究表明，IRIRV的爆发显然与温度有关。体外和体内在不同温度下的病毒增殖实验表明，比目鱼的抗病毒反应是影响HIRRV复制的主要原因。用RNA-Seq分析了在不同温度下感染了IRRV的比目鱼的不同抗病毒反应，实验设定了10℃和20℃两个温度。该比目鱼通过人工注射感染了HIRRV，并在感染后24 h收集脾脏。与此同时，将在不同温度下注射EPC上清液的鱼作为对照组。如果确定单个变量，则可以获得四个成对的比较组，并进一步选择差异表达的基因。结果表明，在10°C和20°C感染HIRRV后，脾脏中差异表达的基因显着丰富了炎症和免疫相关途径，如花生四烯酸代谢，细胞因子与细胞因子受体相互作用，Toll样受体（TLR） ）信号通路，RIG-I样受体（RLRs）信号通路，NOD样受体（NLR）信号通路和胞质DNA感应通路等。此外，吞噬细胞，溶酶体，胞吞相关基因的表达在高温，无论HIRRV为阳性。但与10℃感染的比目鱼相比，RLRs信号通路的某些基因在20℃时显着上调，可以推测RLRs通路可能与比目鱼的抗HIRRV反应有关。因此，RLRs信号通路的关键基因包括选择mda5，lgp2，mita，mavs，irf3，irf7，ifn I-3和ifn-γ，并通过qRT-PCR进一步检测这些基因在不同温度下被感染比目鱼的时间表达模式。结果表明，HIRRV感染可以显着刺激和激活比目鱼的RLRs途径，在20°C时该途径的响应水平显着高于10°C。总的来说，这项研究为进一步研究比目鱼HIRRV感染的发病机理提供了重要的数据。