CAS Key Laboratory of Tropical Marine Bio-resources and Ecology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou, 510301, China; University of Chinese Academy of Sciences, Beijing, 100049, China.
CAS Key Laboratory of Tropical Marine Bio-resources and Ecology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou, 510301, China; Sanya National Marine Ecosystem Research Station, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou, Guangdong, China.
Environ Res. 2024 Jun 1;250:118469. doi: 10.1016/j.envres.2024.118469. Epub 2024 Feb 13.
Global warming reportedly poses a critical risk to coral reef ecosystems. Bacteria and archaea are crucial components of the coral holobiont. The response of archaea associated with warming is less well understood than that of the bacterial community in corals. Also, there have been few studies on the dynamics of the microbial community in the coral holobiont under long-term heat stress. In order to track the dynamic alternations in the microbial communities within the heat-stressed coral holobiont, three-week heat-stress monitoring was carried out on the coral Pocillopora damicornis. The findings demonstrate that the corals were stressed at 32 °C, and showed a gradual decrease in Symbiodiniaceae density with increasing duration of heat stress. The archaeal community in the coral holobiont remained relatively unaltered by the increasing temperature, whereas the bacterial community was considerably altered. Sustained heat stress exacerbated the dissimilarities among parallel samples of the bacterial community, confirming the Anna Karenina Principle in animal microbiomes. Heat stress leads to more complex and unstable microbial networks, characterized by an increased average degree and decreased modularity, respectively. With the extension of heat stress duration, the relative abundances of the gene (nifH) and genus (Tistlia) associated with nitrogen fixation increased in coral samples, as well as the potential pathogenic bacteria (Flavobacteriales) and opportunistic bacteria (Bacteroides). Hence, our findings suggest that coral hosts might recruit nitrogen-fixing bacteria during the initial stages of suffering heat stress. An environment that is conducive to the colonization and development of opportunistic and pathogenic bacteria when the coral host becomes more susceptible as heat stress duration increases.
据报道，全球变暖对珊瑚礁生态系统构成了重大风险。细菌和古菌是珊瑚共生体的重要组成部分。与细菌群落相比，与升温相关的古菌的响应机制还不太清楚。此外，关于在长期热胁迫下珊瑚共生体中微生物群落的动态变化，研究较少。为了跟踪受热胁迫珊瑚共生体中微生物群落的动态变化，对鹿角珊瑚 Pocillopora damicornis 进行了为期 3 周的热胁迫监测。研究结果表明，在 32°C 下珊瑚受到胁迫，并且随着热胁迫持续时间的增加，共生藻 Symbiodiniaceae 的密度逐渐降低。珊瑚共生体中的古菌群落受温度升高的影响相对较小，而细菌群落则发生了很大的变化。持续的热应激加剧了平行样本中细菌群落之间的差异，证实了动物微生物组中的安娜·卡列尼娜原则。热应激导致微生物网络更加复杂和不稳定，分别表现为平均度增加和模块性降低。随着热应激持续时间的延长，与固氮相关的基因（nifH）和属（Tistlia）的相对丰度在珊瑚样本中增加，以及潜在的致病性细菌（Flavobacteriales）和机会性细菌（Bacteroides）。因此，我们的研究结果表明，珊瑚宿主可能在遭受热应激的初始阶段招募固氮细菌。当珊瑚宿主因热应激持续时间增加而变得更容易受到感染时，这种环境有利于机会性和致病性细菌的定植和发展。
