发光细菌PB-P3.9的鉴定与gyrB、luxA基因系统发育分析

Identification and Phylogenetic Analysis Based on gyrB and luxA of Photobacterium PB-P3.9

平板划线分离法从猪肉上分离得到一株发光细菌PB-P3.9,依据细菌DNA促旋酶B亚基基因(gyrB)、荧光素酶A基因(luxA)序列比对及构建系统发育树鉴定其种属,并探讨其来源。扩增gyrB、luxA基因并测序,两个基因序列比对结果与发光杆菌属的明亮发光杆菌(Photobacterium phosphoreum)分别有99%、98%的序列相似性,结合其生物学特性,确定PB-P3.9为一株明亮发光杆菌。根据GenBank数据库中明亮发光杆菌标准菌株gyrB、luxA基因序列,采用距离法构建系统发育树,表明PB-P3.9株与标准菌株NCIMB 1279有最近亲缘关系,结合其生长条件,拟确定此发光细菌PB-P3.9来源于海洋深海鱼或中层海水浮游生物。

Photobacterium strain named PB-P3.9 was isolated from pork by streak plate method.Phylogenetic analysis based on the gyrB and luxA genes was performed.This strain was identified as Photobacterium phosphoreum according to its biological properties and sequence analysis.The gyrB and luxA genes revealed 99% and 98% homology when compared with standard strains.Phylogenetic tree construction based on the standard gyrB and luxA gene sequences published in GenBank was carried out using MEGA4.1 software package by neighbor-joining method.The results showed that this strain had the highest similarity with the standard strain NCIMB1279.Based on their similarities in phylogenetic tree and the growth conditions,it is possible that the isolated strain comes from a marine deep-sea fish such as NCIMB1279,NCIMB1275,NCIMB7 or ATCC11040T,or a middle-level seawater plankton.