Holm Johanna B, Heidelberg Karla B
Division of Marine Environmental Biology, Department of Biological Science, University of Southern California, Los Angeles CA, USA.
Front Microbiol. 2016 Jun 21;7:917. doi: 10.3389/fmicb.2016.00917. eCollection 2016.
Octocorals are sources of novel but understudied microbial diversity. Conversely, scleractinian or reef-building coral microbiomes have been heavily examined in light of the threats of climate change. Muricea californica and Muricea fruticosa are two co-occurring species of gorgonian octocoral abundantly found in the kelp forests of southern California, and thus provide an excellent basis to determine if octocoral microbiomes are host specific. Using Illumina MiSeq amplicon sequencing and replicate samples, we evaluated the microbiomes collected from multiple colonies of both species of Muricea to measure both inter- and intra-colony microbiome variabilities. In addition, microbiomes from overlying sea water and nearby zoanthids (another benthic invertebrate) were also included in the analysis to evaluate whether bacterial taxa specifically associate with octocorals. This is also the first report of microbiomes from these species of Muricea. We show that microbiomes isolated from each sample type are distinct, and specifically, that octocoral species type had the greatest effect on predicting the composition of the Muricea microbiome. Bacterial taxa contributing to compositional differences include distinct strains of Mycoplasma associated with either M. californica or M. fruticosa, an abundance of Spirochaetes observed on M. californica, and a greater diversity of γ-Proteobacteria associated with M. fruticosa. Many of the bacterial taxa contributing to these differences are known for their presence in photosymbiont-containing invertebrate microbiomes.
八放珊瑚是新型但研究不足的微生物多样性来源。相反，造礁石珊瑚或造礁珊瑚微生物群落鉴于气候变化的威胁已得到大量研究。加州软柳珊瑚和丛生软柳珊瑚是两种共生的柳珊瑚八放珊瑚，在南加州的海带林中大量存在，因此为确定八放珊瑚微生物群落是否具有宿主特异性提供了绝佳依据。我们使用Illumina MiSeq扩增子测序和重复样本，评估了从两种软柳珊瑚的多个群体收集的微生物群落，以测量群体间和群体内微生物群落的变异性。此外，分析中还纳入了上层海水和附近的海葵（另一种底栖无脊椎动物）的微生物群落，以评估细菌类群是否与八放珊瑚有特异性关联。这也是关于这些软柳珊瑚物种微生物群落的首份报告。我们表明，从每种样本类型分离出的微生物群落是不同的，具体而言，八放珊瑚物种类型对预测软柳珊瑚微生物群落的组成影响最大。导致组成差异的细菌类群包括与加州软柳珊瑚或丛生软柳珊瑚相关的不同支原体菌株、在加州软柳珊瑚上观察到的大量螺旋体，以及与丛生软柳珊瑚相关的γ-变形菌的更大多样性。导致这些差异的许多细菌类群因其存在于含光合共生体的无脊椎动物微生物群落中而为人所知。
