Department of Marine Ecology, University of Bremen, Bremen, Germany.
Department of Freshwater and Marine Ecology, University of Amsterdam, Amsterdam, The Netherlands.
Sci Rep. 2024 Jun 18;14(1):14019. doi: 10.1038/s41598-024-64828-5.
The mucus surface layer serves vital functions for scleractinian corals and consists mainly of carbohydrates. Its carbohydrate composition has been suggested to be influenced by environmental conditions (e.g., temperature, nutrients) and microbial pressures (e.g., microbial degradation, microbial coral symbionts), yet to what extend the coral mucus composition is determined by phylogeny remains to be tested. To investigate the variation of mucus carbohydrate compositions among coral species, we analyzed the composition of mucosal carbohydrate building blocks (i.e., monosaccharides) for five species of scleractinian corals, supplemented with previously reported data, to discern overall patterns using cluster analysis. Monosaccharide composition from a total of 23 species (belonging to 14 genera and 11 families) revealed significant differences between two phylogenetic clades that diverged early in the evolutionary history of scleractinian corals (i.e., complex and robust; p = 0.001, R = 0.20), mainly driven by the absence of arabinose in the robust clade. Despite considerable differences in environmental conditions and sample analysis protocols applied, coral phylogeny significantly correlated with monosaccharide composition (Mantel test: p < 0.001, R = 0.70). These results suggest that coral mucus carbohydrates display phylogenetic dependence and support their essential role in the functioning of corals.
黏液表层层为石珊瑚提供了重要的功能，主要由碳水化合物组成。其碳水化合物组成被认为受环境条件（如温度、营养物质）和微生物压力（如微生物降解、微生物珊瑚共生体）的影响，但珊瑚黏液组成在多大程度上受系统发育的影响仍有待检验。为了研究黏液碳水化合物组成在珊瑚物种间的变化，我们分析了 5 种石珊瑚的黏膜碳水化合物组成（即单糖），并补充了以前报告的数据，以便使用聚类分析来辨别整体模式。总共 23 个物种（属于 14 个属和 11 个科）的单糖组成表明，在石珊瑚进化史早期分化的两个系统发育枝之间存在显著差异（即复杂和坚固；p=0.001，R=0.20），主要是由于坚固枝系中不存在阿拉伯糖。尽管应用于环境条件和样本分析方案的差异很大，但珊瑚系统发育与单糖组成显著相关（Mantel 检验：p<0.001，R=0.70）。这些结果表明，珊瑚黏液碳水化合物表现出系统发育依赖性，并支持其在珊瑚功能中的重要作用。
