Many corals depend upon the highly specialised and intricate relationship they form with Symbiodiniaceae algal symbionts. Porites lutea is a massive reef-building coral found throughout Southeast Asia that hosts these endosymbionts obligately. Yet despite the prevalence and importance of P. lutea as one of the most dominant corals here, its associated Symbiodiniaceae communities have not been precisely characterised. In this study, we used high-throughput DNA amplicon sequencing of the nuclear internal transcribed spacer 2 (ITS2) to characterise the diversity, community structure and biogeographic distribution of Symbiodiniaceae in P. lutea throughout Singapore and Peninsular Malaysia. Consistent with previous studies, we found that Cladocopium was the most dominant genus among all samples, and Cladocopium C15 was the most dominant type (or subclade) with 100% occurrence in all samples from every study site. Results also revealed numerous Symbiodiniaceae types associated with P. lutea that were previously undetected in Southeast Asia. Endosymbiont diversity and community variation are driven by a combination of site-specific mean monthly cloud cover and variance in monthly sea surface temperature. This study contributes baseline data toward understanding differences in Symbiodiniaceae assemblages hosted by P. lutea, shedding light on how they might be indicative of particular environmental conditions and coral responses.

中文翻译：

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来自东南亚的Porites lutea的内生菌多样性和群落结构是由一系列环境变量驱动的

许多珊瑚依赖它们与共生藻科藻类共生体形成的高度专业化和错综复杂的关系。孔雀石是在整个东南亚发现的大型造礁珊瑚，专心托管这些共生共生体。然而，尽管P. lutea是这里最主要的珊瑚之一，但它的共生共生植物群落尚未得到精确表征。在这项研究中，我们使用了核内转录间隔区2（ITS2）的高通量DNA扩增子测序来表征新加坡和马来西亚半岛黄绿假单胞菌科的共生生物的多样性，群落结构和生物地理分布。与以前的研究一致，我们发现锁骨草是所有样品中最主要的菌种，而Cladocopium C15是最主要的类型（或子进化枝），每个研究地点的所有样品中都有100％的发生。调查结果还显示与相关的众多Symbiodiniaceae类型P.球菌以前在东南亚发现。内生共生体的多样性和群落的变化是由特定地点的平均月云覆盖率和每月海表温度的变化共同驱动的。这项研究为了解P. lutea所携带的共生植物的共生关系提供了基线数据，阐明了它们可能如何指示特定的环境条件和珊瑚反应。