乳山长牡蛎共附生可培养细菌的多样性和副溶血性弧菌拮抗菌的筛选

Diversity of Cultured Symbiotic Bacteria and Screening of Antagonistic Bacteria Against Pathogenic Vibrio parahemolyticus in Pacific Oyster Crassostrea gigas From Rushan,Shandong Province

采用稀释涂布法分离培养2020年6—9月采自山东省威海市乳山牡蛎养殖区的长牡蛎(Crassostrea gigas)胃和鳃部位共附生可培养细菌,通过形态观察和16S rRNA基因测序进行多样性分析,同时筛选副溶血性弧菌的拮抗菌。结果表明:共分离获得细菌422株,删除重复后共获得不同批次细菌258株,主要包括变形菌门、厚壁菌门、放线菌门和拟杆菌门4个类群,分别占比72.2%、12.6%、11.8%和3.4%,共囊括了6个纲,63个属和119个种,并分离到1个潜在新种。分离的不同种类弧菌可能与牡蛎夏季高死亡率有关,并筛选出一株杀鱼假交替单胞菌ML-231对副溶血性弧菌有较强的抑制作用。本研究首次报道了乳山长牡蛎共附生可培养细菌多样性,发现多种致病性弧菌,并获得1株副溶血性弧菌拮抗菌,对今后乳山长牡蛎的生产管理及弧菌防治具有一定参考价值。

Cultured symbiotic bacteria were isolated in stomach and gill of Pacific oyster Crassostrea gigas sampled from a farmer in Rushan,Shandong Province in June,July,August and September 2020 using spread plate method.The diversity was examined based on 16S rRNA gene sequence analysis and antagonistic bacteria against pathogenic Vibrio parahemolyticus were screened.The results showed that a total of 422 strains were isolated and 258 strains unique in 16S r RNA gene sequence were obtained,they being composed of four major lineages including Proteobacteria(72.2%),Firmicutes(12.6%),Actinomycetes(11.8%) and Bacteroidetes(3.4%),and belonging to 6 classes,63 genera and 119 species.Meanwhile 1 strain was identified as potential nova species.Many Vibrio spp.isolated in this study were associated with the summer mortalities of the Pacific oyster.Pseudoalteromonas piscicida ML-231 with strong antimicrobial activity against V.Parahemolyticus was screened.The findings provided important reference with production management and control of Vibrio in the Pacific oyster in the future.