The Oceans Institute (M470), The University of Western Australia, Crawley, Perth, WA, 6009, Australia; School of Plant Biology (M084), The University of Western Australia, Crawley, Perth, WA, 6009, Australia.
Mol Ecol. 2014 Jun;23(12):3113-26. doi: 10.1111/mec.12801. Epub 2014 Jun 10.
Scleractinian corals have demonstrated the ability to shuffle their endosymbiotic dinoflagellate communities (genus Symbiodinium) during periods of acute environmental stress. This has been proposed as a mechanism of acclimation, which would be increased by a diverse and flexible association with Symbiodinium. Conventional molecular techniques used to evaluate Symbiodinium diversity are unable to identify genetic lineages present at background levels below 10%. Next generation sequencing (NGS) offers a solution to this problem and can resolve microorganism diversity at much finer scales. Here we apply NGS to evaluate Symbiodinium diversity and host specificity in Acropora corals from contrasting regions of Western Australia. The application of 454 pyrosequencing allowed for detection of Symbiodinium operational taxonomic units (OTUs) occurring at frequencies as low as 0.001%, offering a 10,000-fold increase in sensitivity compared to traditional methods. All coral species from both regions were overwhelmingly dominated by a single clade C OTU (accounting for 98% of all recovered sequences). Only 8.5% of colonies associated with multiple clades (clades C and D, or C and G), suggesting a high level of symbiont specificity in Acropora assemblages in Western Australia. While only 40% of the OTUs were shared between regions, the dominance of a single OTU resulted in no significant difference in Symbiodinium community structure, demonstrating that the coral-algal symbiosis can remain stable across more than 15° of latitude and a range of sea surface temperature profiles. This study validates the use of NGS platforms as tools for providing fine-scale estimates of Symbiodinium diversity and can offer critical insight into the flexibility of the coral-algal symbiosis.
石珊瑚在面临急性环境压力时表现出了转移共生内共生虫黄藻（属 Symbiodinium）群落的能力。这被认为是一种适应机制，通过与 Symbiodinium 多样化和灵活的关联，这种适应机制将会增强。用于评估 Symbiodinium 多样性的传统分子技术无法识别低于 10%背景水平的遗传谱系。下一代测序 (NGS) 为解决这个问题提供了一种解决方案，可以在更精细的尺度上解析微生物多样性。在这里，我们应用 NGS 来评估西澳大利亚不同地区的鹿角珊瑚中 Symbiodinium 的多样性和宿主特异性。454 焦磷酸测序的应用使得能够检测到频率低至 0.001%的 Symbiodinium 操作分类单位 (OTUs)，与传统方法相比，灵敏度提高了 10,000 倍。来自两个地区的所有珊瑚物种都被单一的 C 类 OTU （占所有回收序列的 98%）所主导。只有 8.5%的珊瑚与多个类群（C 类和 D 类，或 C 类和 G 类）相关，这表明西澳大利亚的鹿角珊瑚集合体中存在高水平的共生特异性。虽然只有 40%的 OTUs 在两个地区共享，但由于单一 OTU 的优势，Symbiodinium 群落结构没有显著差异，这表明珊瑚-藻类共生关系可以在超过 15°的纬度和一系列海面温度分布中保持稳定。这项研究验证了 NGS 平台作为提供 Symbiodinium 多样性精细尺度估计的工具的使用，并为珊瑚-藻类共生关系的灵活性提供了关键的见解。
