引起凡纳滨对虾急性肝胰腺坏死病的副溶血弧菌MLST新序列型

New sequence type isolates of AHPND-causing Vibrio parahaemolyticus from Litopenaeus vannamei by multilocus sequence typing

  • 摘要: 针对12株引起凡纳滨对虾急性肝胰腺坏死病(AHPND)的致病性副溶血弧菌,运用多位点测序技术,分析致病菌株的遗传特征。实验选择副溶血弧菌的7个管家基因dnaEgyrBrecAdtdSpntApyrCtnaA,对12株AHPND致病菌扩增测序。将核酸序列上传至PubMLST数据库进行比对后获得每株菌的序列型。收集其他地区AHPND致病性副溶血弧菌的多位点序列分型(MLST)数据,采用eBURST V3及MEGA 5.0软件进行遗传进化分析。结果显示,2014年中国广东分离的AHPND致病株属于一个新序列型ST1710(42、134、99、79、141、41、51),仅与库中ST415及ST975同源性较高。目前,急性肝胰腺坏死致病株的9种ST型可归为2个克隆组和5个单体。经系统发育树进一步分析可知新序列型ST1710与单体ST975遗传关系相近。本研究首次报道中国AHPND分离株的序列型,丰富了PubMLST数据库,并为其遗传进化研究奠定了理论基础。

     

    Abstract: Twelve strains of pathogenic Vibrio parahaemolyticus isolated from Litopenaeus vannamei with acute hepatopancreatic necrosis disease (AHPND) were chosen, and their genetic characteristics were analyzed by the multilocus sequence typing method. Seven house-keeping genes (dnaE, gyrB, recA, dtdS, pntA, pyrC and tnaA) of V. parahaemolyticus were selected as target genes for PCR amplification and nucleic acid sequencing. The sequences of AHPND-causing V. parahaemolyticus in this study were uploaded to the PubMLST database for multi-alignment to determine the sequence type of each strain. MLST data of AHPND-causing V. parahaemolyticus from other areas were collected and the genetic evolution was analyzed by MEGA 5.0 and eBURST V3 software. AHPND-causing V. parahaemolyticus isolated from Guangdong province in 2014 belonged to the new sequence type ST1710(42, 134, 99, 79, 141, 41, 51). Compared with other sequence types in PubMLST database, it has the high homology with ST415 and ST975. The 9 STs of AHPND-causing V. parahaemolyticus were separated by eBURST into two doublets and five singletons. Phylogenetic tree analysis showed that the new sequence type ST1710 was similar to the singletons ST975. Our study is the first report of molecular epidemiology of AHPND-causing V. parahaemolyticus strains in China using multilocus sequence typing, and enriches the PubMLST database and provides an insight into their evolutionary mechanisms.

     

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