用16S rDNA克隆文库法分析患病刺参幼苗的菌群结构

Flora of diseased juvenile sea cucumber Apostichopus japonicus by 16S rDNA cloning library

采用16S rDNA克隆文库法对某刺参养殖场患病刺参Apostichopus japonicus幼苗（体长为3～5 cm）表皮的菌群结构进行分析。结果表明：化皮参苗病灶组织和未明显化皮参苗表皮菌群均由γ-变形菌纲、β-变形菌纲和α-变形菌纲组成,优势菌为γ-变形菌纲,主要包括志贺氏菌Shigella sp.、不动杆菌Acinetobacter sp.和假单胞菌Pseudomonas sp.;化皮参苗病灶组织中志贺氏菌、不动杆菌和假单胞菌比例分别为49%、17%和5%,未明显化皮参苗表皮中3类菌的比例分别为20%、26%、9%。将该养殖场育苗池海水作为对照并进行菌群结构分析,结果显示,水中菌群同样由γ-变形菌纲、β-变形菌纲和α-变形菌纲组成,优势菌也为γ-变形菌纲,主要包含弧菌Vibrio sp.（75%）与志贺氏菌（12%）。此外,对化皮参苗病灶处进行细菌分离培养,得到一株优势菌,经16S rDNA初步鉴定为弧菌。研究表明,采用16S rDNA克隆文库法所得结果与传统的病原分离培养法存在差异。

Flora on eipthelia of diseased juvenile sea cucumber Apostichopus japonicus with body length of 3-5 cm showing body wall lesions was studied by a method of 16S rDNA cloning library.The results showed that the bacteria were composed of Alphaproteo bacteria,Betaproteo bacteria and Gammaproteo bacteria,with the predominant flora of Shigella sp.,Acinetobacter sp.and Pseudomonas sp.on the lesions of the diseased sea cucumber as well as sea cucumber without obvious symptom.There was 49% of Shigella sp.,17% of Acinetobacter sp.and 5% of Pseudomonas sp.in the diseased sea cucumber,while there was 20% of Shigella sp.,26% of Acinetobacter sp.and 9% of Pseudomonas sp.in those without lesions.The members of Alphaproteo bacteria,Betaproteo bacteria and Gammaproteo bacteria were found in the seawater from the culture ponds as a control group,with predominant phaproteobacteria including Vibrio sp.（ 75%） and Shigella sp.（ 12%）.Also,a predominant bacterium strain was isolated from the diseased cultured sea cucumber by a traditional method based on bacterial culture,and identified as Vibrio sp.by 16S rDNA cloning library.The findings indicate that the predominant flora is varied with the identifying method including a traditional method and 16S rDNA cloning library.