1株军曹鱼病原弧菌的鉴定及其系统发育树分析

Identification and phylogenetic analysis of a pathogenic Vibrio sp.isolated from Rachycentron canadum

从养殖的患病军曹鱼身上分离出1株病原菌JT2,革兰氏阴性,短杆状,有极生鞭毛,能运动,菌落半透明。经回归感染实验,证明该菌为军曹鱼病原菌。进行了常规生理生化实验,并用API-ID32E系统鉴定该菌。再经Biolog-GN细菌鉴定系统鉴定,结果JT2与鲨鱼弧菌(Vibrio carchariae)相似度最高。为了进一步确定该菌的分类学地位,测定了其16SrDNA序列,分析了相关细菌的同源性,构建其系统发育树。结果表明,该菌株与V.carchariae的亲缘关系最近。综合上述几种方法的鉴定结果,最后鉴定该株菌为鲨鱼弧菌V.carchariae。

A pathogenic bacterial strain JT2 was isolated from cobia（Rachycentron canadum）. Morphological observation showed that it was a mobile short-rod gram negative bacterium with polar flagella and translucent. It was proved to be the pathogen of the cobia（Rachycentron canadum ） by the challenge test. The traditional physiological and biochemical experiments were done, and API-ID32E system were applied in the bacterial classification. Identified with Biolog-GN （gram negtive） system again, results showed that strain JT2 was similar to that of Vibrio carchariae in most of the phenotypes. To investigate the phylogenetic position of this pathogen, 16S rDNA of JT2 was sequenced and compared with that of other related strains. Molecular phylogenetic dendrogram was constructed based on the genetic distance analysis. The results showed that strain JT2 exhibited the highest levels of similarity to the V. carchariae. Analysising all the results of several methods, strain JT2 was identified as Vibrio carchariae.