Data from: Gene expression associated with white syndromes in a reef building coral, Acropora hyacinthus

Background: Corals are capable of launching diverse immune defenses at the site of direct contact with pathogens, but the molecular mechanisms of this activity and the colony-wide effects of such stressors remain poorly understood. Here we compared gene expression profiles in eight healthy Acropora hyacinthus colonies against eight colonies exhibiting tissue loss commonly associated with white syndromes, all collected from a natural reef environment near Palau. Two types of tissues were sampled from diseased corals: visibly affected and apparently healthy. Results: Tag-based RNA-Seq followed by weighted gene co-expression network analysis identified groups of co-regulated differentially expressed genes between all health states (disease lesion, apparently healthy tissues of diseased colonies, and fully healthy). Differences between healthy and diseased tissues indicate activation of several innate immunity and tissue repair pathways accompanied by reduced calcification and the switch towards metabolic reliance on stored lipids. Unaffected parts of diseased colonies, although displaying a trend towards these changes, were not significantly different from fully healthy samples. Still, network analysis identified a group of genes, suggestive of altered immunity state, that were specifically up-regulated in unaffected parts of diseased colonies. Conclusions: Similarity of fully healthy samples to apparently healthy parts of diseased colonies indicates that systemic effects of white syndromes on A. hyacinthus are weak, which implies that the coral colony is largely able to sustain its physiological performance despite disease. The genes specifically up-regulated in unaffected parts of diseased colonies, instead of being the consequence of disease, might be related to the originally higher susceptibility of these colonies to naturally occurring white syndromes.

研究背景：珊瑚可在与病原体直接接触的位点启动多样化的免疫防御，但该过程的分子机制以及这类胁迫因子对珊瑚群体的整体影响仍不甚明晰。本研究对采自帕劳附近自然礁区的8个健康杯形轴孔珊瑚（Acropora hyacinthus）群体，与8个表现出常见于白色综合征的组织缺失症状的珊瑚群体进行了基因表达谱对比分析。从患病珊瑚群体中采集了两类组织：肉眼可见的病变组织与外观正常的组织。
研究结果：基于标签的RNA测序（Tag-based RNA-Seq）结合加权基因共表达网络分析，成功鉴定出不同健康状态（病变病灶、患病珊瑚群体的外观正常组织以及完全健康组织）间共调控的差异表达基因模块。健康组织与病变组织间的基因表达差异显示，多条先天免疫与组织修复通路被激活，同时珊瑚的钙化作用减弱，代谢转向依赖储存的脂质供能。患病珊瑚群体的未受影响区域虽呈现出上述变化的趋势，但与完全健康样本并无显著差异。不过，网络分析仍鉴定出一组在患病珊瑚未受影响区域中特异性上调的基因，提示该区域的免疫状态发生了改变。
研究结论：完全健康样本与患病珊瑚群体外观正常组织的基因表达谱高度相似，表明白色综合征对杯形轴孔珊瑚的系统性影响较弱，这意味着即便患病，珊瑚群体仍可在很大程度上维持其生理功能。在患病珊瑚未受影响区域中特异性上调的基因，并非疾病进程的产物，反而可能与这些珊瑚群体原本对自然发生的白色综合征具有更高易感性相关。