Mutualistic microalgae co-diversify with reef corals that acquire symbionts during egg development
Mutualistic microalgae co-diversify with reef corals that acquire symbionts during egg development
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DOI：
10.1038/s41396-021-01007-8
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发表时间：
2021-05
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影响因子：
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通讯作者：
Kira E. Turnham;D. Wham;E. Sampayo;T. Lajeunesse
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作者：
Kira E. Turnham;D. Wham;E. Sampayo;T. Lajeunesse
分子遗传学的应用使物种的定义和科学调查方式得到了振兴和改进，特别是对于形态上神秘的微生物。在这里，我们展示了物种识别如何提高对造礁珊瑚和互惠甲藻（即共生藻科）之间的生态和互惠进化的理解。遗传、生态和形态学证据的结合定义了Cladocopium的两个兄弟物种（以前的Symbiodinium Clade C），仅特异于Pocilopora常见属中的宿主珊瑚，这些珊瑚在卵子发生过程中传递其专性共生体。nov.与P. grandis/meandrinwhile the smaller-celledC.太平洋种nov.与P.疣状的这两种共生体都与Pocillopora形成共生关系，并孕育它们的后代。每个物种的种群，就像它们的宿主一样，在热带和亚热带太平洋之间有着很好的遗传联系，这表明它们具有远距离传播的能力。分子钟近似于上新世晚期或更新世早期的物种形成，因为地球经历了急剧的冷却和变暖周期;并且对应于它们的宿主也多样化的时候。高宿主忠诚度的长期时空维持，以及数千公里的遗传连接性，表明独特的生态属性和密切的进化历史将抑制珊瑚及其专门共生体对快速气候变暖的适应性反应。
The application of molecular genetics has reinvigorated and improved how species are defined and investigated scientifically, especially for morphologically cryptic micro-organisms. Here we show how species recognition improves understanding of the ecology and evolution of mutualisms between reef-building corals and their mutualistic dinoflagellates (i.e. Symbiodiniaceae). A combination of genetic, ecological, and morphological evidence defines two sibling species ofCladocopium(formerlySymbiodiniumClade C), specific only to host corals in the common genusPocillopora, which transmit their obligate symbionts during oogenesis.Cladocopium latusorumsp. nov. is symbiotic withP. grandis/meandrinawhile the smaller-celledC. pacificumsp. nov. associates withP. verrucosa. Both symbiont species form mutualisms withPocilloporathat brood their young. Populations of each species, like their hosts, are genetically well connected across the tropical and subtropical Pacific Ocean, indicating a capacity for long-range dispersal. A molecular clock approximates their speciation during the late Pliocene or early Pleistocene as Earth underwent cycles of precipitous cooling and warming; and corresponds to when their hosts were also diversifying. The long temporal and spatial maintenance of high host fidelity, as well as genetic connectivity across thousands of kilometers, indicates that distinct ecological attributes and close evolutionary histories will restrain the adaptive responses of corals and their specialized symbionts to rapid climate warming.