回头岸礁区4 种造礁珊瑚中可培养细菌的多样性

采用稀释涂布平板法,分离三亚鹿回头岸礁区4种造礁珊瑚及其周围海水中的细菌,并基于16S r RNA基因序列进行了系统发育分析,从而探讨造礁珊瑚中可培养细菌的物种多样性。从澄黄滨珊瑚(Porites lutea)、鹿角珊瑚(Acropora sp.)、盔形珊瑚(Galaxea sp.)、扁脑珊瑚(Platygyra sp.)样品中分别分离获得细菌60、61、54、20株,从珊瑚周边海水中分离获得细菌31株。16S r RNA基因序列分析表明,珊瑚来源的细菌分布于放线菌门(Actinobacteria)、α-变形菌纲(Alphaproteobacteria)、γ-变形菌纲(Gammaproteobacteria)、厚壁菌门(Firmicutes)和拟杆菌门(Bacteroidetes)。在属级水平上对4种珊瑚及海水来源细菌群落组成分析,发现在4种珊瑚中均有分布的属有3个,为Brachybacterium、Microbacterium和Ruegeria,珊瑚来源细菌类群有一定差异。同时发现4种珊瑚来源细菌与海水来源细菌类群差异较大。在分离的菌株中,有7株菌与已有效描述的细菌物种典型菌株的全长16S r RNA基因相似性低于97%,代表着潜在新属或新种。试验结果表明,三亚鹿回头岸礁区珊瑚中存在较为丰富的细菌多样性,并潜藏较多的新物种资源。

Diversity of culturable bacteria associated with four scleractinian corals located in Luhuitou fringing reef

In order to reveal the diversity of culturable bacteria associated with corals, the spread plate methodwas used to isolate bacteria from 4 coral species samples and the surrounding seawater, and phylogenetic analysiswas carried out based on the 16S rRNA gene sequences. A total of 60 strains were isolated from Porites lutea, 61strains were isolated from Acropora sp., 54 strains were isolated from Galaxea sp., 20 strains were isolated fromPlatygyra sp., and 31 strains were isolated from seawater. Phylogenetic analysis showed that these isolates weredistributed in Actinobacteria, Alphaproteobacteria, Gammaproteobacteria, Firmicutes and Bacteroidetes. GeneraBrachybacterium, Microbacterium and Ruegeria were present in all four coral samples. Moreover, culturable coralassociatedbacteria groups were distinct from seawater. Among these isolates, the levels of 16S rRNA gene sequencesimilarity between 7 strains and their respective closest neighbours were lower than 97%. This result suggested thatthese isolates were candidate novel species. This is the first report on the diversity of culturable bacteria associatedwith corals in Luhuitou fringing reef, Sanya. The results indicate that culturable bacteria associated with scleractinian corals is abundant and diverse, and scleractinian corals are a promising source of novel bacteria species.