采用16S rDNA片段鉴定鳗鲡病原菌的初步研究

Classification of Pathogenic Bacteria Isolated from Eels by Partial 16S rDNA Sequencing

初步探讨了采用16S rDNA片段鉴定鳗鲡病原菌的方法.根据已知细菌16S rDNA序列的高度保守区设计引物,利用PCR法扩增16株已鉴定的鳗鲡病原菌的16S rDNA片段,测序分析后,通过Gen-Bank数据库进行同源性检索,并构建相应的系统发育树.结果表明:16株鳗鲡病原菌均扩增到了400 bp左右的基因片段,其中14株菌的16S rDNA片段序列与网上已发表的同属菌株的同源性为100%,其余2株为99%;8株病原菌被鉴定到种,分别属于嗜水气单胞菌和温和气单胞菌,其余8株被鉴定到属,分别属于气单胞菌属、假单胞菌属和肠杆菌属;鉴定结果与生化鉴定结果在属的分类单元上的符合程度高达82%.

This study mainly focused on classification and identification of pathogenic bacteria isolated from eels by partial 16S rDNA sequencing.Methods：Primers were designed based on the previously published high conserved 16S rDNA gene sequences,and the partial 16S rDNA sequences of 16 strains of pathogenic bacteria were amplified and sequenced.The sequences were aligned with those published sequences retrieved from GenBank and the phylogenetic tree was then constructed based on the analysis with Clustalw software.Results：It showed that all of the 16 tested pathogenic bacteria strains were amplified about 400 bp products;the partial 16S rDNA sequence homologies were 100 % between the 14 tested stains and the same genius strains in the NCBI,and the other 2 were 99 %;8 tested strains were identified to Aeromonas.hydrophila and Aeromonas.sobria,and the other 8 tested strains were identified to Aeromonas genus,Pseudomonas genus and Enterobacter genus;the results of the alignment and clustering analysis was about 82 % accordance with the results of physiological and biochemical identification of the isolates.Conclusions：All these results indicated that 16S rDNA sequence analysis offered a novel,convenient,economical,and valid tool for classification of pathogenic bacteria isolated from eels.