DataSheet_1_Edwardsiella piscicida infection reshapes the intestinal microbiome and metabolome of big-belly seahorses: mechanistic insights of synergistic actions of virulence factors.docx

Uncovering the mechanism underlying the pathogenesis of Edwardsiella piscicida-induced enteritis is essential for global aquaculture. In the present study, we identified E. piscicida as a lethal pathogen of the big-belly seahorse (Hippocampus abdominalis) and revealed its pathogenic pattern and characteristics by updating our established bacterial enteritis model and evaluation system. Conjoint analysis of metagenomic and metabolomic data showed that 15 core virulence factors could mutually coordinate the remodeling of intestinal microorganisms and host metabolism and induce enteritis in the big-belly seahorse. Specifically, the Flagella, Type IV pili, and Lap could significantly increase the activities of the representative functional pathways of both flagella assembly and bacterial chemotaxis in the intestinal microbiota (P < 0.01) to promote pathogen motility, adherence, and invasion. Legiobactin, IraAB, and Hpt could increase ABC transporter activity (P < 0.01) to compete for host nutrition and promote self-replication. Capsule1, HP-NAP, and FarAB could help the pathogen to avoid phagocytosis. Upon entering epithelial cells and phagocytes, Bsa T3SS and Dot/Icm could significantly increase bacterial secretion system activity (P < 0.01) to promote the intracellular survival and replication of the pathogen and the subsequent invasion of the neighboring tissues. Finally, LPS3 could significantly increase lipopolysaccharide biosynthesis (P < 0.01) to release toxins and kill the host. Throughout the pathogenic process, BopD, PhoP, and BfmRS significantly activated the two-component system (P < 0.01) to coordinate with other VFs to promote deep invasion. In addition, the levels of seven key metabolic biomarkers, Taurine, L-Proline, Uridine, L-Glutamate, Glutathione, Xanthosine, and L-Malic acid, significantly decreased (P < 0.01), and they can be used for characterizing E. piscicida infection. Overall, the present study systematically revealed how a combination of virulence factors mediate E. piscicida-induced enteritis in fish for the first time, providing a theoretical reference for preventing and controlling this disease in the aquaculture of seahorses and other fishes.

揭示迟钝爱德华氏菌（Edwardsiella piscicida）诱导肠炎的致病机制，对全球水产养殖业至关重要。本研究鉴定出迟钝爱德华氏菌为宽腹海马（Hippocampus abdominalis）的致死性病原体，并通过更新我们已建立的细菌性肠炎模型与评价体系，阐明了其致病模式与特征。对宏基因组（metagenomic）与代谢组（metabolomic）数据的联合分析显示，15种核心毒力因子可协同调控肠道微生物群与宿主代谢的重塑，并诱导宽腹海马发生肠炎。具体而言，鞭毛（Flagella）、IV型菌毛（Type IV pili）及Lap可显著提升肠道菌群中鞭毛组装与细菌趋化这两类代表性功能通路的活性（P < 0.01），从而促进病原体的运动、黏附与入侵。莱格巴汀（Legiobactin）、IraAB与Hpt可增强ABC转运蛋白（ABC transporter）活性（P < 0.01），以竞争宿主营养并促进自身增殖。荚膜1（Capsule1）、HP-NAP与FarAB可帮助病原体逃避宿主的吞噬作用。当病原体侵入上皮细胞与吞噬细胞后，Bsa T3SS与Dot/Icm可显著提升细菌分泌系统的活性（P < 0.01），从而促进病原体在胞内的存活与增殖，并进一步入侵邻近组织。最终，脂多糖3（LPS3）可显著增强脂多糖生物合成通路活性（P < 0.01），以释放毒素并致死宿主。在整个致病过程中，BopD、PhoP与BfmRS可显著激活双组分系统（two-component system，P < 0.01），与其他毒力因子协同促进病原体的深度入侵。此外，7种关键代谢生物标志物——牛磺酸（Taurine）、L-脯氨酸（L-Proline）、尿苷（Uridine）、L-谷氨酸（L-Glutamate）、谷胱甘肽（Glutathione）、黄苷（Xanthosine）与L-苹果酸（L-Malic acid）的水平显著降低（P < 0.01），可用于表征迟钝爱德华氏菌的感染状态。本研究首次系统阐明了多种毒力因子协同介导鱼类迟钝爱德华氏菌诱导肠炎的分子机制，为防控海马及其他鱼类水产养殖业中的此类病害提供了理论参考。