河川沙塘鳢病原杀鲑气单胞菌致病性及感染后宿主免疫相关基因差异表达分析  

Pathogenicity of Aeromonas salmonicida and differential expression of immune-related genes in Odontobutis potamophila after infection

作　　者：李杰 刘国兴 钱且奇[1] 朱玉洁 陈圳 姜群 王骏 张晓君 高晓建[1] LI Jie;LIU Guoxing;QIAN Qieqi;ZHU Yujie;CHEN Zhen;JIANG Qun;WANG Jun;ZHANG Xiaojun;GAO Xiaojian(College of Animal Science and Technology,Yangzhou University,Yangzhou 225009,Jiangsu,China;Freshwater Fishery Research Institute of Jiangsu Province,Nanjing 210017,China)

机构地区：[1]扬州大学动物科学与技术学院,江苏扬州225009 [2]江苏省淡水水产研究所,南京210017

出　　处：《淡水渔业》2024年第1期45-56,共12页Freshwater Fisheries

基　　金：江苏省现代农业产业技术体系(JATS[2022]415);江苏省农业重大新品种创制项目(PZCZ201743)。

摘　　要：为探明2021年3月常熟某养殖场河川沙塘鳢(Odontobutis potamophilus)疾病暴发的原因,本研究从患病鱼体内分离到优势菌株,通过形态观察、理化特性测定及gyrB基因同源性分析鉴定优势菌,同时通过人工感染试验、组织病理观察、毒力因子及毒力基因检测确定其致病性,并测定分离菌的耐药性和感染后河川沙塘鳢免疫相关基因表达变化。结果显示:引起河川沙塘鳢大量死亡的病原菌为杀鲑气单胞菌(Aeromonas salmonicida)。代表菌株G2-4-1对河川沙塘鳢的LD 50为1.8×106 CFU/mL;该病原菌感染可引起河川沙塘鳢肝脏、脾脏、肾脏和鳃组织出现明显的变性、坏死和炎性细胞浸润;该菌株携带aer、hly、exu等毒力基因,且具有蛋白酶、卵磷脂酶、淀粉酶、脂酶、明胶酶和溶血素活性,但不具有DNA酶活性;耐药性分析发现,分离菌G2-4-1对青霉素G、氨苄西林、苯唑西林等8种药物耐药,对克拉霉素和大观霉素2种药物中介,对恩诺沙星、氟苯尼考等24类药物敏感;免疫相关基因表达分析显示,在感染初期MHCⅡB、MyD88、TLR和SOD在鳃、脾脏和肾脏组织中都显著上调表达。The dominant strain was isolated from the diseased fish in this study to investigate the cause of the disease outbreak of Odontobutis potamophilus in a farm in Changshu in March 2021.The dominant bacterium was identified by morphological observation,physicochemical characterization and gyrB gene homology analysis.The pathogenicity of the isolates was determined by artificial infection test,histopathological observation,virulence factor,and virulence gene detection,and the drug resistance and immune-related gene expression changes of the isolates were determined after infection.The results showed that the pathogen causing the mass death of Odontobutis potamophilus was Aeromonas salmonicida(OM203113).The LD 50 of the representative strain G2-4-1 to Odontobutis potamophilus was 1.8×106 CFU/mL.Infection with the pathogenic bacteria in Odontobutis potamophilus can cause obvious degeneration,necrosis and inflammatory cell infiltration in the liver,spleen,kidney and gill tissues.The strain carries aer,hly,exu and other virulence genes,and has protease,lecithinase,amylase,lipase,gelatinase and hemolysin activities but does not have DNase activity.The drug resistance analysis showed that the isolate G2-4-1 was resistant to 8 drugs including penicillin G,ampicillin,and oxacillin,2 drugs intermediary to clarithromycin and spectinomycin,sensitive to 24 drugs such as enrofloxacin,florfenicol.Immune-related gene expression analysis showed that MHCⅡB,MyD88,TLR and SOD were significantly up-regulated in gill,spleen and head kidney tissues at the early stage of infection.It provides a scientific basis for the prevention,control,and treatment of bacterial disease of A.salmonicida.

关 键 词：河川沙塘鳢(Odontobutis potamophilus) 杀鲑气单胞菌(Aeromonas salmonicida) 致病性 组织病理 免疫相关基因 

分 类 号：S941[农业科学—水产养殖]