Wuxi Fisheries College, Nanjing Agricultural University, Wuxi, 214081, China.
Key Laboratory of Freshwater Fisheries and Germplasm Resources Utilization, Ministry of Agriculture, Freshwater Fisheries Research Center, Chinese Academy of Fishery Sciences, Wuxi, 214081, China.
BMC Microbiol. 2018 Jun 4;18(1):52. doi: 10.1186/s12866-018-1178-8.
Iron plays important roles in the growth, reproduction and pathogenicity of Aeromonas hydrophila. In this study, we detected and compared the mRNA and protein expression profiles of A. hydrophila under normal and iron restricted medium with 200 μM 2,2-Dipyridyl using RNA Sequencing (RNA-seq) and isobaric tags for relative and absolute quantification (iTRAQ) analyses.
There were 1204 genes (601 up- and 603 down-regulated) and 236 proteins (90 up- and 146 down-regulated) shown to be differentially expressed, and 167 genes and proteins that showed consistent expression. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses revealed that the differentially expressed genes and proteins were mainly involved in iron ion transport, protein activity, energy metabolism and virulence processes. Further validation of the RNA-seq and iTRAQ results by quantitative real-time PCR (qPCR) revealed that 18 of the 20 selected genes were consistently expressed. The iron-ion absorption and concentration of A. hydrophila under iron-limited conditions were enhanced, and most virulence factors (protease activity, hemolytic activity, lipase activity, and swimming ability) were also increased. Artificial A. hydrophila infection caused higher mortality in cyprinid Megalobrama amblycephala under iron-limited conditions.
Understanding the responses of pathogenic Aeromonas hydrophila within the hostile environment of the fish host, devoid of free iron, is important to reveal bacterial infection and pathogenesis. This study further confirmed the previous finding that iron-limitation efficiently enhanced the virulence of A. hydrophila using multi-omics analyses. We identified differentially expressed genes and proteins, related to enterobactin synthesis and virulence establishment, that play important roles in addressing iron scarcity.
铁在嗜水气单胞菌的生长、繁殖和致病性中起着重要作用。在这项研究中，我们使用 RNA 测序（RNA-seq）和同位素标记相对和绝对定量（iTRAQ）分析，检测并比较了正常和铁限制培养基（200μM 2,2-二吡啶）中嗜水气单胞菌的 mRNA 和蛋白质表达谱。
有 1204 个基因（601 个上调和 603 个下调）和 236 个蛋白（90 个上调和 146 个下调）表现出差异表达，有 167 个基因和蛋白表现出一致的表达。基因本体论（GO）和京都基因与基因组百科全书（KEGG）富集分析表明，差异表达的基因和蛋白主要参与铁离子转运、蛋白活性、能量代谢和毒力过程。通过定量实时 PCR（qPCR）对 RNA-seq 和 iTRAQ 结果进一步验证，20 个选定基因中有 18 个表现出一致的表达。在缺铁条件下，嗜水气单胞菌的铁离子吸收和浓度增加，大多数毒力因子（蛋白酶活性、溶血活性、脂肪酶活性和游泳能力）也增加。在缺铁条件下，人工嗜水气单胞菌感染导致鲫鱼（Megalobrama amblycephala）的死亡率更高。
了解无游离铁的鱼类宿主恶劣环境中致病性嗜水气单胞菌的反应对于揭示细菌感染和发病机制非常重要。本研究进一步证实了以前的发现，即铁限制有效地增强了多组学分析中嗜水气单胞菌的毒力。我们确定了与铁载体合成和毒力建立相关的差异表达基因和蛋白，它们在应对缺铁方面发挥着重要作用。
