Temperature-regulated bleaching and lysis of the coral Pocillopora damicornis by the novel pathogen Vibrio coralliilyticus
Temperature-regulated bleaching and lysis of the coral Pocillopora damicornis by the novel pathogen Vibrio coralliilyticus
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DOI：
10.1128/aem.69.7.4236-4242.2003
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发表时间：
2003-07-01
影响因子：
4.4
通讯作者：
Rosenberg, E
中科院分区：
文献类型：
--
作者：
Ben-Haim, Y;Zicherman-Keren, M;Rosenberg, E
珊瑚白化是珊瑚动物与其光合微藻内共生体（虫黄藻）之间共生关系的破坏。有人认为大规模的白化事件与全球变暖有关。这里提供的数据表明，解珊瑚弧菌是大角珊瑚白化的病原体。这种细菌在白化的大角珊瑚中含量很高，但在健康的珊瑚中不存在。这种细菌是在纯培养物中分离出来的，并进行了微生物学表征，结果表明，当它在 25 摄氏度下接种到健康珊瑚上时，会引起白化。从受感染珊瑚的患病组织中重新分离出病原体。细菌漂白珊瑚中的虫黄藻浓度低于健康珊瑚中虫黄藻浓度的 12%。当 P. damicornis 在较高温度（27 和 29 摄氏度）下感染 V. Coralliidyticus 时，珊瑚会在两周内裂解，这表明海水温度是决定感染结果的关键环境参数。在珊瑚从白化到裂解的转变相同的温度范围（24 至 28 摄氏度）下，V. Coralliilyticus 的胞外蛋白酶活性水平大幅增加。我们认为，P. damicornis 的漂白是由于对藻类的攻击造成的，而细菌诱导的裂解和死亡是由细菌细胞外蛋白酶促进的。这里提供的数据支持珊瑚白化的细菌假说。
Coral bleaching is the disruption of symbioses between coral animals and their photosynthetic microalgal endosymbionts (zooxanthellae). It has been suggested that large-scale bleaching episodes are linked to global warming. The data presented here demonstrate that Vibrio coralliilyticus is an etiological agent of bleaching of the coral Pocillopora damicornis. This bacterium was present at high levels in bleached P. damicornis but absent from healthy corals. The bacterium was isolated in pure culture, characterized microbiologically, and shown to cause bleaching when it was inoculated onto healthy corals at 25degreesC. The pathogen was reisolated from the diseased tissues of the infected corals. The zooxanthella concentration in the bacterium-bleached corals was less than 12% of the zooxanthella concentration in healthy corals. When P. damicornis was infected with V. coralliidyticus at higher temperatures (27 and 29degreesC), the corals lysed within 2 weeks, indicating that the seawater temperature is a critical environmental parameter in determining the outcome of infection. A large increase in the level of the extracellular protease activity of V. coralliilyticus occurred at the same temperature range (24 to 28degreesC) as the transition from bleaching to lysis of the corals. We suggest that bleaching of P. damicornis results from an attack on the algae, whereas bacterium-induced lysis and death are promoted by bacterial extracellular proteases. The data presented here support the bacterial hypothesis of coral bleaching.