Some corals may become more resistant to bleaching by shuffling their Symbiodiniaceae communities toward thermally tolerant species, and manipulations to boost the abundance of these symbionts in corals may increase resilience in warming oceans. However, the thermotolerant symbiont Durusdinium trenchii may reduce growth and fecundity in Caribbean corals, and these tradeoffs need to be better understood as this symbiont spreads through the region. We sought to understand how D. trenchii modulates coral gene expression by manipulating symbiont communities in Montastraea cavernosa to produce replicate ramets containing D. trenchii together with paired ramets of these same genets (n  = 3) containing Cladocopium C3 symbionts. We then examined differences in global gene expression between corals hosting Durusdinium and Cladocopium under control temperatures, and in response to short‐term heat stress. We identified numerous transcriptional differences associated with symbiont identity, which explained 2%–14% of the transcriptional variance. Corals with D. trenchii upregulated genes related to translation, ribosomal structure and biogenesis, and downregulated genes related to extracellular structures, and carbohydrate and lipid transport and metabolism, relative to corals with Cladocopium . Unexpectedly, these changes were similar to those observed in Cladocopium‐ dominated corals in response to heat stress, suggesting that thermotolerant D. trenchii may cause corals to increase expression of heat stress‐responsive genes, explaining both the increased heat tolerance and the associated energetic tradeoffs in corals containing D. trenchii . These findings provide insight into the ecological changes occurring on contemporary coral reefs in response to climate change, and the diverse ways in which different symbionts modulate emergent phenotypes of their hosts.

中文翻译：

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耐热珊瑚共生体调节宿主的热应激反应基因。

某些珊瑚可能通过将其共生菌科改组为耐热物种而变得更耐漂白，而增加珊瑚中这些共生菌的含量的操作可能会增加变暖海洋中的复原力。然而，耐热共生体杜氏球藻可能会降低加勒比海珊瑚的生长和繁殖力，随着这种共生体在整个区域的扩散，需要更好地理解这些折衷。我们试图了解D.Trenchii如何通过操纵Montastraea cavernosa中的共生菌群落来调节珊瑚基因表达，以产生含D.Trenchii的复制品和同等品系（n  = 3）的配对品。ado兰C3共生体。然后，我们在控制温度下以及响应短期热应激的情况下，研究了硬粒杜鹃和锁兰的珊瑚之间全球基因表达的差异。我们发现了与共生体身份相关的众多转录差异，这解释了2％–14％的转录差异。相对于含角藻科的珊瑚而言，具有沟纹D.的珊瑚上调了与翻译，核糖体结构和生物发生有关的基因，并下调了与细胞外结构以及碳水化合物和脂质运输和代谢有关的基因。出乎意料的是，这些变化与在紫花苜蓿中观察到的相似。优势珊瑚对热胁迫的反应，这表明耐热的海沟D可能会导致珊瑚增加热应激反应基因的表达，这解释了含海沟D的珊瑚的耐热性增加和相关的能量折衷。这些发现提供了对当代珊瑚礁响应气候变化而发生的生态变化的见解，以及不同共生体调节其寄主表型的多种方式。