EAPSI: Reconstructing the evolutionary history of coral-microbe associations to identify microbial taxa important to the health of their coral host

珊瑚礁生态系统正处于全球迅速衰退的状态。研究表明，许多重要的压力因素，包括海水温度升高，营养负荷和疾病，可能会破坏珊瑚与细菌和其他微生物的自然联系，从而损害珊瑚。微生物作为一个整体已被证明在珊瑚健康中发挥重要作用，提供必要的营养物质，抵抗病原体，甚至通过提示发展。然而，确定提供这些益处的特定微生物类群一直具有挑战性。因此，很难评估压力源介导的微生物群落变化对珊瑚的健康影响。该项目将试图通过重建珊瑚微生物协会的进化历史和确定特定协会的自然选择特征来发现生理上重要的微生物。这项研究将与澳大利亚海洋科学研究所的著名珊瑚微生物学专家大卫伯恩博士合作进行。澳大利亚多样化的珊瑚礁拥有21个主要珊瑚分支中的15个，提供了一个独特的机会，可以从进化上不同但地理上相同的珊瑚物种中采集广泛的组织样本。目前，这些分支中只有3个分支的微生物组受到了显著的关注。使用标记基因和宏基因组的高通量测序创建的这些社区的基线描述将允许识别特定珊瑚分支内的集群分类群。这种分析将通过处理微生物类群和功能作为可以针对中性进化的零模型进行测试的性格特征来进行。未来的研究将能够集中在这些类群作为假定的互利主义者，其中断可能会减少珊瑚健康。这项研究最终将允许更准确地预测各种环境压力的环境影响。这个NSF EAPSI奖是与澳大利亚科学院合作资助的。

Coral reef ecosystems are in a state of rapid global decline. Research has suggested that many important stressors, including elevated sea temperatures, nutrient loading, and disease, may harm corals by disrupting their natural associations with bacteria and other microbes. Microbes as a whole have been shown to play important roles in coral health by providing essential nutrients, resisting pathogens, and even by cueing development. However, it has been challenging to identify the specific microbial taxa that provide these benefits. The health consequences to corals of stressor-mediated microbial community shifts are thus difficult to assess. This project will attempt to discover physiologically important microbes by reconstructing the evolutionary history of coral-microbe associations and identifying signatures of natural selection for particular associations. The research will be conducted in collaboration with Dr. David Bourne, a noted expert in coral microbiology, at the Australian Institute of Marine Science. The diverse reefs of Australia harbor up to 15 of the 21 major coral clades, providing a unique opportunity to sample a broad selection of tissue from evolutionarily divergent but geographically concurrent coral species. Currently, the microbiomes of only 3 of these clades have received any significant attention. A baseline description of these communities, created using high throughput sequencing of marker-genes and metagenomes, will allow the identification of taxa that cluster within particular coral clades. This analysis will be performed by treating microbial taxa and functions as character traits that can be tested against a null model of neutral evolution. Future studies will be able to focus on these taxa as putative mutualists, whose disruption may reduce coral health. This research will eventually allow more accurate prediction of the environmental effects of various environmental stressors. This NSF EAPSI award is funded in collaboration with the Australian Academy of Science.