School of Life Sciences, Xiamen University; Fujian Collaborative Innovation Center for Exploitation and Utilization of Marine Biological Resources, Xiamen, Fujian 361005, China.
State Key Laboratory Breeding Base of Marine Genetic Resources; Key Laboratory of Marine Genetic Resources, Third Institute of Oceanography, State Oceanic Administration; Key Laboratory of Marine Genetic Resources of Fujian Province, Xiamen 361005, China.
Sci Rep. 2017 Feb 9;7:42100. doi: 10.1038/srep42100.
In the South China Sea, coastal eutrophication in the Beibu Gulf has seriously threatened reef habitats by subjecting corals to chronic physiological stress. To determine how coral holobionts may tolerate such conditions, we examined the transcriptomes of healthy colonies of the galaxy coral Galaxea fascicularis and its endosymbiont Symbiodinium from two reef sites experiencing pristine or eutrophied nutrient regimes. We identified 236 and 205 genes that were differentially expressed in eutrophied hosts and symbionts, respectively. Both gene sets included pathways related to stress responses and metabolic interactions. An analysis of genes originating from each partner revealed striking metabolic integration with respect to vitamins, cofactors, amino acids, fatty acids, and secondary metabolite biosynthesis. The expression levels of these genes supported the existence of a continuum of mutualism in this coral-algal symbiosis. Additionally, large sets of transcription factors, cell signal transduction molecules, biomineralization components, and galaxin-related proteins were expanded in G. fascicularis relative to other coral species.
在中国南海，北部湾沿岸富营养化严重威胁着珊瑚礁栖息地，使珊瑚长期处于生理压力之下。为了确定珊瑚共生体如何能耐受这种环境，我们检测了来自两个珊瑚礁地点的健康星系珊瑚（Galaxea fascicularis）及其共生藻（Symbiodinium）的转录组。这两个珊瑚礁地点的营养条件分别处于原始状态或富营养化状态。我们在富营养化宿主和共生藻中分别鉴定到了 236 个和 205 个差异表达的基因。这两组基因都包括与应激反应和代谢相互作用相关的途径。对来自每个共生伙伴的基因的分析显示，在维生素、辅助因子、氨基酸、脂肪酸和次生代谢物生物合成方面存在显著的代谢整合。这些基因的表达水平支持了这种珊瑚-藻类共生关系中存在连续共生的观点。此外，相对于其他珊瑚物种，星系珊瑚中大量的转录因子、细胞信号转导分子、生物矿化成分和与 galaxin 相关的蛋白得到了扩展。
