In order to develop successful strategies for coral reef preservation, it is critical that the biology of both host corals and symbiotic algae are investigated. In the Ryukyu Archipelago, which encompasses many islands spread over approximately 500 km of the Pacific Ocean, four major populations of the coral Acropora digitifera have been studied using whole genome shotgun (WGS) sequence analysis (Shinzato et al. 2015). In contrast, the diversity of the symbiotic dinoflagellates associated with these A. digitifera populations is unknown. It is therefore unclear if these two core components of the coral holobiont share a common evolutionary history. This issue can be addressed for the symbiotic algal populations by studying the organelle genomes of their mitochondria and plastids. Here we analyzed WGS data from ∼150 adult A. digitifera, and by mapping reads to the available reference genome sequences, we extracted 2,250 sequences representing 15 organelle genes of Symbiodiniaceae. Molecular phylogenetic analyses of these mitochondrial and plastid gene sets revealed that A. digitifera from the southern Yaeyama islands harbor a different Symbiodiniaceae population than the islands of Okinawa and Kerama in the north, indicating that the distribution of symbiont populations partially matches that of the four host populations. Interestingly, we found that numerous single-nucleotide polymorphisms (SNPs) correspond to known RNA-edited sites in 14 of the Symbiodiniaceae organelle genes, with mitochondrial genes showing a stronger correspondence than plastid genes. These results suggest a possible correlation between RNA editing and SNPs in the two organelle genomes of symbiotic dinoflagellates.

中文翻译：

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珊瑚鞭毛藻与恐龙鞭毛的细胞器遗传变异与RNA编辑之间的相关性。

为了制定成功的珊瑚礁保护策略，至关重要的是研究寄主珊瑚和共生藻类的生物学特性。在琉球群岛（Ryukyu Archipelago）涵盖了分布在太平洋约500公里处的许多岛屿，已使用全基因组shot弹枪（WGS）序列分析研究了四个主要种群的趾甲珊瑚（Shinzato et al。2015）。相比之下，与这些数字指藻种群相关的共生鞭毛藻的多样性是未知的。因此，尚不清楚珊瑚全生命线的这两个核心组成部分是否具有共同的进化史。通过研究共生藻类线粒体和质体的细胞器基因组，可以解决该问题。在这里，我们分析了约150个成年指骨成虫的WGS数据，通过将读段映射到可用的参考基因组序列，我们提取了2250个序列，它们代表共生植物的15个细胞器基因。对这些线粒体和质体基因集的分子系统发育分析表明，八重山南部岛屿的指骨草不同于北部的冲绳岛和庆良间岛，拥有不同的共生菌科种群，这表明共生菌种群的分布与四个宿主的分布部分匹配人口。有趣的是，我们发现许多单核苷酸多态性（SNP）对应于Symbiodiniaceae细胞器基因的14个中已知的RNA编辑位点，线粒体基因比质体基因显示出更强的对应性。