Shuffling between Cladocopium and Durusdinium extensively modifies the physiology of each symbiont without stressing the coral host
Shuffling between Cladocopium and Durusdinium extensively modifies the physiology of each symbiont without stressing the coral host
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DOI：
10.1111/mec.16190
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发表时间：
2021-10-05
影响因子：
4.9
通讯作者：
Matz, Mikhail
中科院分区：
文献类型：
--
作者：
Abbott, Evelyn;Dixon, Groves;Matz, Mikhail
随着海面温度的升高，许多曾经是枝珊瑚属共生体的珊瑚物种已经被耐热属Durusdinium所占领。在这里，我们询问了一个属的共生体中的基因表达如何根据同一珊瑚宿主内另一个共生体属的丰度而变化，以及这种相互作用对宿主有什么影响。共生体基因的表达绝大多数受宿主内属是多数还是少数的影响，影响了所有基因的79% （Durusdinium）和96% （Cladocopium）。在这两个属中，光合作用成分（在少数状态下上调）和推测与细胞运动相关的蛋白质（在多数状态下上调）被观察到特别强烈的影响。重要的是，当两个属在宿主体内的比例相当时，没有明显的基因表达特征与混合共生状态相关，这可能导致更激烈的竞争。混合共生也与宿主应激升高无关：事实上，热处理后，与Cladocopium和durusdinium主导的珊瑚相比，混合共生珊瑚的应激特征最低。综上所述，在Cladocopium和Durusdinium之间的洗牌过程中，这两个共生属都经历了广泛的、很大程度上互惠的生理转变，但没有证据表明它们之间的拮抗相互作用会加剧，从而对宿主有害。除非本研究中的混合共生珊瑚不是Cladocopium和Durusdinium之间的典型过渡的代表，否则从一个共生属到另一个共生属的洗色过程对珊瑚宿主来说似乎是无成本的，甚至似乎与较低的胁迫敏感性有关。这让人们对未来的珊瑚感到乐观，它们可能不得不越来越多地依靠共生洗牌来抵御环境挑战。
As sea surface temperatures increase, many coral species that used to harbour symbionts of the genus Cladocopium have become colonized with the thermally tolerant genus, Durusdinium. Here, we asked how gene expression in the symbionts of one genus changes depending on the abundance of another symbiont genus within the same coral host, and what effect this interaction has on the host. Symbiont gene expression was overwhelmingly driven by whether the genus was the minority or the majority within the host, which affected 79% (Durusdinium) and 96% (Cladocopium) of all genes. Particularly strong effects in both genera were observed for photosynthesis components (upregulated in the minority state) and proteins putatively associated with cell motility (upregulated in the majority state). Importantly, there was no distinct gene expression signature associated with the mixed symbiosis state when both genera were represented in comparable proportions within the host, which could lead to more intense competition. The mixed symbiosis was also not associated with elevated host stress: in fact, after heat treatment, stress signatures were the lowest in mixed-symbiosis corals compared to both Cladocopium- and Durusdinium-dominated corals. In conclusion, during shuffling between Cladocopium and Durusdinium both symbiont genera go through extensive and largely reciprocal physiological transitions, but there is no evidence of intensifying antagonistic interactions that are detrimental to the host. Unless the mixed-symbiosis corals in this study are not representative of the typical transition between Cladocopium and Durusdinium, the process of shuffling from one symbiont genus to another appears to be cost-free for the coral host, and even appears to be associated with lower stress susceptibility. This raises optimism for the future corals, which will probably have to rely on symbiont shuffling more and more to withstand environmental challenges.