甜菜夜蛾Hop基因的鉴定及其在抵御囊泡病毒HvAV-3h侵染过程中的免疫调控作用

Identification of the Hop gene in beet armyworm Spodoptera exigua and its immunoregulatory role in response to Heliothis virescens ascovirus 3h(HvAV-3h) infection

中文关键词:甜菜夜蛾  Hop基因  JAK-STAT信号通路  囊泡病毒  RNA干扰  细胞凋亡

keywords:Spodoptera exigua  Hop gene  JAK-STAT signaling pathway  ascovirus  RNA interference  apoptosis

中文摘要:为探究甜菜夜蛾Spodoptera exigua中Janus络氨酸激酶跳房子（Hopscotch,Hop）基因在先天免疫应答中的功能及其在抵御囊泡病毒HvAV-3h侵染过程中的作用，基于甜菜夜蛾转录组数据鉴定获得SeHop基因，对其序列特征、系统进化及保守结构域进行分析；利用实时荧光定量PCR检测HvAV-3h侵染不同时间下SeHop的表达模式；进一步分析干扰该基因且HvAV-3h侵染对甜菜夜蛾脂肪体细胞凋亡、线粒体膜电位及活性氧水平的影响。结果显示：甜菜夜蛾SeHop编码1 114个氨基酸，具有典型的Hop家族结构域，与近缘种具有高度相似性。HvAV-3h侵染早期（0～24 h），甜菜夜蛾体内SeHop基因表达显著上调，其中侵染后2 h内表达变化最大。沉默SeHop基因48 h且HvAV-3h侵染2 h后，甜菜夜蛾脂肪体细胞的凋亡程度较对照显著增强，线粒体膜电位较对照显著降低，活性氧大量积累。表明SeHop基因作为Janus激酶-信号转导子与转录激活子信号（Janus kinase-signal transducers and activators of transcription,JAK-STAT）通路关键组分，在甜菜夜蛾抵御HvAV-3h侵染的早期免疫应答中发挥着重要作用，其机制涉及调控细胞凋亡与氧化应激过程。

Abstract:To investigate the function of the Janus tyrosine kinase Hopscotch(Hop) gene in the innate immune response of beet armyworm Spodoptera exigua and its role resistance to ascovirus HvAV-3h infection, the SeHop gene was identified based on transcriptome data from S. exigua, and its sequence characteristics, phylogenetic relationships, and conserved domains were analyzed. Real-time quantitative PCR was used to detect the expression pattern of SeHop at different time points after HvAV-3h infection. Furthermore, the effects of SeHop gene silencing combined with HvAV-3h infection on apoptosis, mitochondrial membrane potential, and reactive oxygen species(ROS) levels in fat body cells of S. exigua were analyzed. The results showed that S. exigua SeHop encodes 1 114 amino acids and contains typical Hop family domains, exhibiting high conservation with closely related species. During the early stage of HvAV-3h infection(0-24 h), SeHop gene expression in S. exigua was significantly upregulated, with the most dramatic changes occurring within two hours post-infection. After SeHop was silenced for 48 h followed by HvAV-3h infection for two hours, apoptosis in fat body cells of S. exigua was significantly enhanced compared to the control, mitochondrial membrane potential was significantly reduced, and ROS accumulated substantially. These findings indicate that the SeHop gene, as a key component of the Janus kinase-signal transducer and activator of transcription(JAK-STAT) signaling pathway, plays an important role in the early immune response of S. exigua against HvAV-3h infection, and its mechanism involves the regulation of apoptosis and oxidative stress.