Thermal stress triggers productive viral infection of a key coral reef symbiont
Thermal stress triggers productive viral infection of a key coral reef symbiont
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DOI：
10.1038/s41396-022-01194-y
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发表时间：
2022-01-19
期刊：
影响因子：
11
通讯作者：
Correa, Adrienne M. S.
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文献类型：
--
作者：
Grupstra, Carsten G. B.;Howe-Kerr, Lauren, I;Correa, Adrienne M. S.
气候变化驱动的海洋变暖正在增加漂白事件的频率和严重程度，其中珊瑚在失去甲藻内共生体（共生藻科）后出现白化。共生菌科的病毒感染可能会导致一些漂白的迹象，但很少有经验证据支持这一假设。我们首次对珊瑚群落中感染共生藻科的正义单链RNA病毒（“dinoRNAV”）谱系进行了时间分析，这些珊瑚群落暴露于5天的热处理（+2.1摄氏度）。在实验中，从两个密切相关的Pocilopora-Cladocopia（珊瑚共生体）组合的5个菌落中检测到总共124个dinoRNAV主要衣壳蛋白基因“氨基型”（独特的氨基酸序列）;大多数dinoRNAV氨基型在两个珊瑚共生体组合（64%）和多个菌落（82%）之间共享。在整个实验中，仅在热处理的片段中发现了17种dinoRNAV氨基型，并且在热处理的片段中以较高的相对丰度检测到22种氨基型。在热胁迫下，一些菌落片段中的DinoRNAV表现出更高的α多样性和分散性。总之，这些发现提供了第一个经验证据，即暴露于高温会触发一些dinoRNAVs在热应激珊瑚中从持续性感染模式转变为生产性感染模式。在较长的时间范围内，我们假设，累积dinoRNAV生产的Pocillopora Cladocopia系统可能会影响殖民地共生状态，例如，通过减少珊瑚内的共生藻科密度。这项研究为白化事件期间dinoRNAV动态的珊瑚礁规模调查奠定了基础。
Climate change-driven ocean warming is increasing the frequency and severity of bleaching events, in which corals appear whitened after losing their dinoflagellate endosymbionts (family Symbiodiniaceae). Viral infections of Symbiodiniaceae may contribute to some bleaching signs, but little empirical evidence exists to support this hypothesis. We present the first temporal analysis of a lineage of Symbiodiniaceae-infecting positive-sense single-stranded RNA viruses ("dinoRNAVs") in coral colonies, which were exposed to a 5-day heat treatment (+2.1 degrees C). A total of 124 dinoRNAV major capsid protein gene "aminotypes" (unique amino acid sequences) were detected from five colonies of two closely related Pocillopora-Cladocopium (coral-symbiont) combinations in the experiment; most dinoRNAV aminotypes were shared between the two coral-symbiont combinations (64%) and among multiple colonies (82%). Throughout the experiment, seventeen dinoRNAV aminotypes were found only in heat-treated fragments, and 22 aminotypes were detected at higher relative abundances in heat-treated fragments. DinoRNAVs in fragments of some colonies exhibited higher alpha diversity and dispersion under heat stress. Together, these findings provide the first empirical evidence that exposure to high temperatures triggers some dinoRNAVs to switch from a persistent to a productive infection mode within heat-stressed corals. Over extended time frames, we hypothesize that cumulative dinoRNAV production in the Pocillopora-Cladocopium system could affect colony symbiotic status, for example, by decreasing Symbiodiniaceae densities within corals. This study sets the stage for reef-scale investigations of dinoRNAV dynamics during bleaching events.