Zhang Yanying, Yang Qingsong, Zhang Ying, Ahmad Manzoor, Ling Juan, Tang Xiaoyu, Dong Junde
Ocean School, Yantai University, Yantai 264005, China.
CAS Key Laboratory of Tropical Marine Bio-resources and Ecology, South China Sea Institute of Oceanology, Guangzhou 510301, China; Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou), Guangzhou 511458, China.
Sci Total Environ. 2021 May 10;768:144631. doi: 10.1016/j.scitotenv.2020.144631. Epub 2021 Jan 2.
Coral bacteria are highly dynamic and acutely affected by host health and environmental conditions. However, there is limited knowledge of how the dynamics of coral-associated bacterial communities and interactions among bacterial members change in response to dissolved inorganic nutrient stressors. Here, we used high-throughput sequencing of the 16S rRNA gene to examine dynamic changes in coral-associated bacterial communities under elevated ammonium stress. Short-term exposure to high levels of ammonium does not significantly harm coral holobiont. Physiological parameters such as carbohydrate, chlorophyll a, and lipid content of coral holobiont were not affected. After three weeks of elevated ammonium stress, however, the coral-associated bacterial community changed significantly. The abundance of certain bacterial populations increased significantly, with enrichment of pathogenic and opportunistic bacteria and a decrease in defensive and core bacteria. Keystone bacterial species in the co-occurrence network changed considerably. Under elevated ammonium stress, the abundance of keystone species associated with corals was lower and the complexity of keystone bacterial relationships decreased significantly. Our results indicate that bacteria respond to elevated ammonium stress through changes in abundance and co-occurrence among bacterial members. This precedes visual symptoms of changes in coral physiological conditions and could be used as an early warning indicator of elevated ammonium stress in coastal coral reef management.
珊瑚细菌具有高度动态性，并受到宿主健康和环境条件的严重影响。然而，对于与珊瑚相关的细菌群落动态以及细菌成员之间的相互作用如何响应溶解无机营养应激源的变化，我们了解有限。在此，我们利用16S rRNA基因的高通量测序技术，研究了在铵胁迫升高情况下与珊瑚相关的细菌群落的动态变化。短期暴露于高水平的铵不会对珊瑚共生体造成显著损害。珊瑚共生体的生理参数，如碳水化合物、叶绿素a和脂质含量均未受到影响。然而，在铵胁迫升高三周后，与珊瑚相关的细菌群落发生了显著变化。某些细菌种群的丰度显著增加，致病和机会性细菌富集，防御性和核心细菌减少。共现网络中的关键细菌物种发生了相当大的变化。在铵胁迫升高的情况下，与珊瑚相关联的关键物种丰度较低，关键细菌关系的复杂性显著降低。我们的结果表明，细菌通过细菌成员之间丰度和共现的变化来响应铵胁迫升高。这先于珊瑚生理状况变化的可见症状，可作为沿海珊瑚礁管理中铵胁迫升高的早期预警指标。
