Mohamed Amin R, Andrade Natalia, Moya Aurelie, Chan Cheong Xin, Negri Andrew P, Bourne David G, Ying Hua, Ball Eldon E, Miller David J
CSIRO Agriculture and Food, Queensland Bioscience Precinct, St Lucia, Qld, Australia.
Zoology Department, Faculty of Science, Benha University, Benha, Egypt.
Mol Ecol. 2020 Oct;29(20):3921-3937. doi: 10.1111/mec.15612. Epub 2020 Sep 21.
Despite the ecological significance of the mutualistic relationship between Symbiodiniaceae and reef-building corals, the molecular interactions during establishment of this relationship are not well understood. This is particularly true of the transcriptional changes that occur in the symbiont. In the current study, a dual RNA-sequencing approach was used to better understand transcriptional changes on both sides of the coral-symbiont interaction during the colonization of Acropora tenuis by a compatible Symbiodiniaceae strain (Cladocopium goreaui; ITS2 type C1). Comparison of transcript levels of the in hospite symbiont 3, 12, 48 and 72 hr after exposure to those of the same strain in culture revealed that extensive and generalized down-regulation of symbiont gene expression occurred during the infection process. Included in this "symbiosis-derived transcriptional repression" were a range of stress response and immune-related genes. In contrast, a suite of symbiont genes implicated in metabolism was upregulated in the symbiotic state. The coral data support the hypothesis that immune-suppression and arrest of phagosome maturation play important roles during the establishment of compatible symbioses, and additionally imply the involvement of some SCRiP family members in the colonization process. Consistent with previous ecological studies, the transcriptomic data suggest that active translocation of metabolites to the host may begin early in the colonization process, and thus that the mutualistic relationship can be established at the larval stage. This dual RNA-sequencing study provides insights into the transcriptomic remodelling that occurs in C. goreaui during transition to a symbiotic lifestyle and the novel coral genes implicated in symbiosis.
尽管共生藻科与造礁珊瑚之间的互利共生关系具有生态学意义，但这种关系建立过程中的分子相互作用仍未得到充分理解。共生体中发生的转录变化尤其如此。在本研究中，采用了双RNA测序方法，以更好地了解在细枝鹿角珊瑚被一种相容的共生藻科菌株（戈尔罗克洛多虫；ITS2 C1型）定殖期间，珊瑚 - 共生体相互作用双方的转录变化。将定殖3、12、48和72小时后宿主体内共生体的转录水平与该菌株在培养物中的转录水平进行比较，发现共生体基因表达在感染过程中发生了广泛而普遍的下调。这种“共生衍生的转录抑制”包括一系列应激反应和免疫相关基因。相比之下，一组与代谢相关的共生体基因在共生状态下上调。珊瑚数据支持以下假设：免疫抑制和吞噬体成熟停滞在相容共生关系的建立过程中起重要作用，此外还暗示了一些SCRiP家族成员参与定殖过程。与先前的生态学研究一致，转录组数据表明，代谢物向宿主的主动转运可能在定殖过程早期就开始了，因此互利共生关系可以在幼虫阶段建立。这项双RNA测序研究为戈尔罗克洛多虫向共生生活方式转变过程中发生的转录组重塑以及与共生相关的新的珊瑚基因提供了见解。
