Vohsen Samuel A, Herrera Santiago
Department of Biological Sciences, Lehigh University, Bethlehem, PA, USA.
Lehigh Oceans Research Center, Lehigh University, Bethlehem, PA, USA.
Environ Microbiome. 2024 Jun 10;19(1):38. doi: 10.1186/s40793-024-00579-0.
Coral-associated microbiomes vary greatly between colonies and localities with functional consequences on the host. However, the full extent of variability across the ranges of most coral species remains unknown, especially for corals living in deep waters which span greater ranges. Here, we characterized the microbiomes of four octocoral species from mesophotic and bathyal deep-sea habitats in the northern Gulf of Mexico, Muricea pendula, Swiftia exserta, Callogorgia delta, and Paramuricea biscaya, using 16S rRNA gene metabarcoding. We sampled extensively across their ranges to test for microbiome differentiation between and within species, examining the influence of environmental factors that vary with depth (53-2224 m) and geographic location (over 680 m) as well as the host coral's genotype using RAD-sequencing.
Coral microbiomes were often dominated by amplicon sequence variants whose abundances varied across their hosts' ranges, including symbiotic taxa: corallicolids, Endozoicomonas, members of the Mollicutes, and the BD1-7 clade. Coral species, depth, and geographic location significantly affected diversity, microbial community composition, and the relative abundance of individual microbes. Depth was the strongest environmental factor determining microbiome structure within species, which influenced the abundance of most dominant symbiotic taxa. Differences in host genotype, bottom temperature, and surface primary productivity could explain a significant part of the microbiome variation associated with depth and geographic location.
Altogether, this work demonstrates that the microbiomes of corals in deep waters vary substantially across their ranges in accordance with depth and other environmental conditions. It reveals that the influence of depth on the ecology of mesophotic and deep-sea corals extends to its effects on their microbiomes which may have functional consequences. This work also identifies the distributions of microbes including potential parasites which can be used to inform restoration plans in response to the Deepwater Horizon oil spill.
珊瑚相关微生物群落因珊瑚个体和地理位置的不同而有很大差异，对宿主具有功能性影响。然而，大多数珊瑚物种分布范围内的变异程度仍不清楚，尤其是对于生活在分布范围更广的深水中的珊瑚。在这里，我们使用16S rRNA基因代谢条形码技术，对来自墨西哥湾北部中光层和深海栖息地的四种八放珊瑚物种——垂枝软珊瑚（Muricea pendula）、突出软珊瑚（Swiftia exserta）、三角洲卡洛珊瑚（Callogorgia delta）和比斯开副软珊瑚（Paramuricea biscaya）的微生物群落进行了特征分析。我们在它们的分布范围内进行了广泛采样，以测试物种间和物种内微生物群落的分化情况，研究随深度（53 - 2224米）和地理位置（超过680米）变化的环境因素以及使用RAD测序技术检测宿主珊瑚基因型的影响。
珊瑚微生物群落通常由扩增子序列变体主导，其丰度在宿主的分布范围内有所不同，包括共生类群：珊瑚内共生菌、内共生单胞菌属、柔膜菌纲成员以及BD1 - 7进化枝。珊瑚物种、深度和地理位置显著影响多样性、微生物群落组成以及个体微生物的相对丰度。深度是决定物种内微生物群落结构的最强环境因素，它影响了大多数优势共生类群的丰度。宿主基因型、底层温度和表层初级生产力的差异可以解释与深度和地理位置相关的微生物群落变异的很大一部分。
总之，这项工作表明，深水中珊瑚的微生物群落在其分布范围内会根据深度和其他环境条件而有很大变化。它揭示了深度对中光层和深海珊瑚生态的影响延伸到了对其微生物群落的影响，这可能具有功能性后果。这项工作还确定了包括潜在寄生虫在内的微生物分布，可用于为应对“深水地平线”漏油事件的恢复计划提供信息。
