线纹海马肠道菌群结构与功能对迟钝爱德华氏菌(Edwardsiella tarda)感染的响应特征研究

Dysbiosis of both structure and function of intestinal microbiota in lined seahorses(Hippocampus erectus)as response to Edwardsiella tarda infection

细菌性肠炎对海马养殖业影响巨大,但病原对海马肠道菌群的具体影响尚不清楚。文章利用已分离的病原细菌Edwardsiella tarda YT1和海马细菌性肠炎模型,结合16S rDNA高通量测序技术,探究病原细菌侵染对海马肠道菌群的影响。结果发现,E.tarda侵染改变了海马肠道菌群的结构组成、多样性和丰度,并显著降低了其多样性(p<0.05);显著增加了海马肠道变形菌门(Proteobacteria)的相对丰度(p<0.05),减少了放线菌门(Actinobacteria)、厚壁菌门(Firmicutes)、拟杆菌门(Bacteroidetes)的相对丰度(p<0.05);导致致病菌爱德华氏菌属(Edwardsiella)在属水平的相对丰度极显著增加(p<0.01),而肠道固有菌群嗜冷杆菌属(Psychrobacter)和罗氏菌属(Rothia)极显著减少(p<0.01),以及球菌属(Macrococcus)与动球菌属(Planococcus)显著减少(p<0.05)。研究结果表明,E.tarda能通过改变海马肠道固有优势菌群的相对丰度导致菌群失调。菌群功能变化及其相关性分析表明,E.tarda可能通过显著提高细菌趋化性、鞭毛组装、ABC转运蛋白、磷酸转运酶系统以及脂多糖生物合成途径的活性(p<0.05),抑制肠道核心菌群如嗜冷杆菌属、动球菌属和谷氨酸杆菌属的丰度及其核糖体、RNA降解、核苷酸剪切修复与脂肪酸生物合成途径的活性(p<0.05),导致肠道菌群功能失调,并诱发肠炎。

Bacterial enteritis can cause severe damage to seahorse aquaculture,while little is known about the effects of bacterial pathogen infection on intestinal microbiota of seahorses.In the present study,both bacterial pathogen(Edwardsiella tarda YT1)and seahorse research model of bacterial enteritis previously reported by us were employed to explore the role of bacterial pathogen in intestinal microbiota by high-throughput full-length 16S rRNA gene sequencing.The results showed that E.tarda infection significantly altered the composition and abundance,and significantly decreased diversity of intestinal microbiota of lined seahorses(p<0.05);significantly increased the relative abundance of Proteobacteria(p<0.05),and decreased the abundance of Actinobacteria,Firmicutes,and Bacteroidetes(p<0.05);significantly increased the relative abundance of pathogenic Edwardsiella(p<0.01),while decreasing that of Psychrobacter,Rothia,Macrococcus,and Planococcus(p<0.05)at genera level.It indicates that E.tarda infection can reduce the diversity and relative abundance of intestinal autochthonous microbiota and result in dysbiosis in lined seahorses.Based on the results of bacterial function and correlation,increasing relatively abundance of E.tarda may significantly upregulate its activities of bacterial chemotaxis,flagella assembly,ABC transporter,phosphotransferase system,and lipopolysaccharide biosynthesis pathways(p<0.05),cause decrease of the relative abundance of the core intestinal microbiota of Psychrobacter,Planococcus and Glutamicibacter and suppression of their functional activities of ribosome,RNA degradation,nucleotide excision repair,and fatty acid biosynthesis pathways(p<0.05),induce dysbiosis of intestinal microbiota,and finally result in enteritis.These results may be helpful for further revealing pathogenic mechanism of E.tarda-induced enteritis in seahorses by more detailed metagenomic and metabolomics analysis.