サンゴやイソギンチャクは藻類と共生関係にあり、栄養分を交換している。新しい研究では、このパートナーシップが細胞レベルでどのように制御されているかが明らかになった。 Corals and anemones engage in symbiotic relationships with algae and swap nutrients with them. A new study shows how this partnership is regulated at cell level.
2023-08-14 ミュンヘン大学(LMU)
◆この結果は、共生サンゴのエネルギー取得と安定性に大きな影響を与え、サンゴと藻の複雑な相互作用が長い共進化の過程で進化してきた可能性がある。
<関連情報>
- https://www.lmu.de/en/newsroom/news-overview/news/underwater-molecular-barter.html
- https://www.sciencedirect.com/science/article/pii/S0960982223009776
刺胞動物-渦鞭毛藻共生における宿主栄養センシングはmTORシグナルによって媒介される Host nutrient sensing is mediated by mTOR signaling in cnidarian-dinoflagellate symbiosis
Philipp A. Voss, Sebastian G. Gornik, Marie R. Jacobovitz, Sebastian Rupp, Melanie Dörr, Ira Maegele, Annika Guse
Current Biology Published: August 11, 2023
DOI:https://doi.org/10.1016/j.cub.2023.07.038
Highlights
•Symbiosis activates mTOR signaling in the cnidarian host at the symbiosome
•Disruption to mTOR signaling results in loss of symbionts (dysbiosis)
•Functional mTOR signaling and nutrient exchange are crucial for symbiosis stability
Summary
To survive in the nutrient-poor waters of the tropics, reef-building corals rely on intracellular, photosynthetic dinoflagellate symbionts. Photosynthates produced by the symbiont are translocated to the host, and this enables corals to form the structural foundation of the most biodiverse of all marine ecosystems. Although the regulation of nutrient exchange between partners is critical for ecosystem stability and health, the mechanisms governing how nutrients are sensed, transferred, and integrated into host cell processes are largely unknown. Ubiquitous among eukaryotes, the mechanistic target of the rapamycin (mTOR) signaling pathway integrates intracellular and extracellular stimuli to influence cell growth and cell-cycle progression and to balance metabolic processes. A functional role of mTOR in the integration of host and symbiont was demonstrated in various nutritional symbioses, and a similar role of mTOR was proposed for coral-algal symbioses. Using the endosymbiosis model Aiptasia, we examined the role of mTOR signaling in both larvae and adult polyps across various stages of symbiosis. We found that symbiosis enhances cell proliferation, and using an Aiptasia-specific antibody, we localized mTOR to symbiosome membranes. We found that mTOR signaling is activated by symbiosis, while inhibition of mTOR signaling disrupts intracellular niche establishment and symbiosis altogether. Additionally, we observed that dysbiosis was a conserved response to mTOR inhibition in the larvae of a reef-building coral species. Our data confim that mTOR signaling plays a pivotal role in integrating symbiont-derived nutrients into host metabolism and symbiosis stability, ultimately allowing symbiotic cnidarians to thrive in challenging environments.
