Key Laboratory of Marine Biogenetic Resources, Third Institute of Oceanography, State Oceanic Administration, Xiamen, China.
BMC Genomics. 2010 Sep 22;11:506. doi: 10.1186/1471-2164-11-506.
The large yellow croaker (Pseudosciaena crocea) is an economically important marine fish in China suffering from severe outbreaks of infectious disease caused by marine bacteria such as Aeromonas hydrophila (A. hydrophila), resulting in great economic losses. However, the mechanisms involved in the immune response of this fish to bacterial infection are not fully understood. To understand the molecular mechanisms underlying the immune response to such pathogenic bacteria, we used high-throughput deep sequencing technology to investigate the transcriptome and comparative expression profiles of the large yellow croaker infected with A. hydrophila.
A total of 13,611,340 reads were obtained and assembled into 26,313 scaffolds in transcriptional responses of the A. hydrophila-infected large yellow croaker. Via annotation to the NCBI database, we obtained 8216 identified unigenes. In total, 5590 (68%) unigenes were classified into Gene Ontology, and 3094 unigenes were found in 20 KEGG categories. These genes included representatives from almost all functional categories. By using Solexa/Illumina's DeepSAGE, 1996 differentially expressed genes (P value < 0.05) were detected in comparative analysis of the expression profiles between A. hydrophila-infected fish and control fish, including 727 remarkably upregulated genes and 489 remarkably downregulated genes. Dramatic differences were observed in genes involved in the inflammatory response. Bacterial infection affected the gene expression of many components of signaling cascades, including the Toll-like receptor, JAK-STAT, and MAPK pathways. Genes encoding factors involved in T cell receptor (TCR) signaling were also revealed to be regulated by infection in these fish.
Based on our results, we conclude that the inflammatory response may play an important role in the early stages of infection. The signaling cascades such as the Toll-like receptor, JAK-STAT, and MAPK pathways are regulated by A. hydrophila infection. Interestingly, genes encoding factors involved in TCR signaling were revealed to be downregulated by infection, indicating that TCR signaling was suppressed at this early period. These results revealed changes of multiple signaling pathways involved in immunity during A. hydrophila infection, which will facilitate our comprehensive understanding of the mechanisms involved in the immune response to bacterial infection in the large yellow croaker.
大黄鱼（Pseudosciaena crocea）是中国一种重要的经济鱼类，深受水产养殖者的喜爱。然而，近年来，大黄鱼经常遭受由海洋细菌（如嗜水气单胞菌（A. hydrophila））引起的严重传染病的爆发，给水产养殖业造成了巨大的经济损失。然而，大黄鱼对细菌感染的免疫反应的分子机制尚不完全清楚。为了了解这种病原细菌感染的免疫反应的分子机制，我们使用高通量深度测序技术研究了感染嗜水气单胞菌的大黄鱼的转录组和比较表达谱。
从转录组应答的大黄鱼中获得了 13611340 个reads，并组装成 26313 个支架。通过对 NCBI 数据库的注释，我们获得了 8216 个鉴定的基因。总共，5590（68%）个基因被分类到 GO 数据库中，3094 个基因被分类到 20 个 KEGG 类别中。这些基因几乎包含了所有功能类别的代表。通过使用 Solexa/Illumina 的 DeepSAGE，在感染嗜水气单胞菌的鱼和对照组鱼的表达谱的比较分析中检测到 1996 个差异表达基因（P 值<0.05），包括 727 个显著上调基因和 489 个显著下调基因。在炎症反应相关基因中观察到显著差异。细菌感染影响了信号转导途径中许多成分的基因表达，包括 Toll 样受体、JAK-STAT 和 MAPK 途径。在这些鱼中，还发现编码 T 细胞受体（TCR）信号相关因子的基因受到感染的调节。
基于我们的结果，我们认为炎症反应可能在感染的早期阶段发挥重要作用。Toll 样受体、JAK-STAT 和 MAPK 等信号转导途径受到嗜水气单胞菌感染的调节。有趣的是，编码 TCR 信号相关因子的基因被感染下调，表明在这个早期阶段 TCR 信号被抑制。这些结果揭示了在嗜水气单胞菌感染过程中参与免疫的多个信号通路的变化，这将有助于我们全面理解大黄鱼对细菌感染的免疫反应的机制。
