琼东海域珊瑚共附生放线菌的多样性

Diversity of coral-associated actinobacteria in the east coast of Hainan Island

应用免培养方法与可培养方法相结合的方式对琼东海域6种珊瑚样品中的共附生放线菌进行研究,具体为滨珊瑚(Porite)、扁脑珊瑚(Platygyra)、角蜂巢珊瑚(Favites)、盔形珊瑚(Galaxea)和鹿角珊瑚(Acropora).免培养方法中,利用放线菌特异性引物对样品总DNA进行16S rRNA基因序列扩增,并将扩增产物进行Miseq高通量测序,测序结果分析表明,6种珊瑚样品中的放线菌序列属于37个分类单元,主要分布在酸微菌目、棒杆菌目、微球菌目、丙酸杆菌目和假诺卡式菌目,其中37.8%的分类单元与已有效发表菌株的序列相似性小于97%,可能代表着放线菌新的类群.可培养方法中,通过6种培养基分得137株放线菌,分属于放线菌门放线菌纲5个目11个科下的20个属,优势类群为分枝杆菌属(Mycobacterium)、考克氏菌属(Kocuria)和微球菌属(Micrococcus),其中放线孢菌属(Actinomycetospora)、柠檬球菌属(Citricoccus)和涅斯捷连科氏菌属(Nesterenkonia)是第一次从珊瑚样品中发现;琼东海域珊瑚共附生放线菌多样性丰富,新类型的放线菌资源挖掘潜力比较大.

In this study,six coral samples belonging to the genera Porite,Platygyra,Favites,Galaxea,Acropora and Favia were sampled from the east coast of Hainan Island. Diversity of coral-associated actinobacteria was investigated using culture-dependent and culture-independent approaches. Specific primers for the phylum Actinobacteria were used to amplify the actinobacterial 16 S rRNA gene,and 16 S rRNA gene libraries were constructed and sequenced with the Illumina Mi Seq platform. The analysis of 16 S rRNA gene sequences showed that the actinobacterial sequences were grouped in 37 OTUs on the basis of 97% sequence similarity within one OTU. These OTUs mainly belonged to classes Acidimicrobiales,Corynebacteriales,Micrococcales,Propionibacteriales and Pseudonocardiales. 37. 8 % of these OTUs showed less than 97% 16 S rRNA gene sequence similarity with validly published species and represented novel taxa. A total of 137 strains were isolated used six different media. As results,they belong to 20 known genera,among them the genera Mycobacterium,Kocuria and Micrococcus were the dominants.The genera Actinomycetospora,Citricoccus and Nesterenkonia were first isolated from coral hosts. Cumulatively,the east coast of Hainan Island harbors abundant actinobacteria,including large number of unknown actinobacterial groups.