Department of Chemical and Environmental Engineering, University of California, Riverside, Riverside, CA 92521, USA; Center for Plant Cell Biology, Department of Botany and Plant Sciences, University of California, Riverside, Riverside, CA 92521, USA; Carnegie Institution for Science, Department of Plant Biology, Stanford, CA 94305, USA.
Department of Chemical and Environmental Engineering, University of California, Riverside, Riverside, CA 92521, USA; Department of Microbiology, University of California, Riverside, Riverside, CA 92521, USA.
Curr Biol. 2022 Jun 6;32(11):2402-2415.e4. doi: 10.1016/j.cub.2022.04.021. Epub 2022 May 2.
Photosynthesis shapes the symbiotic relationships between cnidarians and Symbiodiniaceae algae-with many cnidarian hosts requiring symbiont photosynthate for survival-but little is known about how photosynthesis impacts symbiosis establishment. Here, we show that during symbiosis establishment, infection, proliferation, and maintenance can proceed without photosynthesis, but the ability to do so is dependent on specific cnidarian-Symbiodiniaceae relationships. The evaluation of 31 pairs of symbiotic relationships (five species of Symbiodiniaceae in sea anemone, coral, and jellyfish hosts) revealed that infection can occur without photosynthesis. A UV mutagenesis method for Symbiodiniaceae was established and used to generate six photosynthetic mutants that can infect these hosts. Without photosynthesis, Symbiodiniaceae cannot proliferate in the sea anemone Aiptasia or jellyfish Cassiopea but can proliferate in the juvenile polyps of the coral Acropora. After 6 months of darkness, Breviolum minutum is maintained within Aiptasia, indicating that Symbiodiniaceae maintenance can be independent of photosynthesis. Manipulating photosynthesis provides insights into cnidarian-Symbiodiniaceae symbiosis.
光合作用塑造了刺胞动物和共生藻类（Symbiodiniaceae）之间的共生关系——许多刺胞动物宿主的生存都依赖于共生藻的光合作用产物——但对于光合作用如何影响共生关系的建立却知之甚少。在这里，我们表明，在共生关系建立、感染、增殖和维持的过程中，光合作用可以不参与其中，但这种能力取决于特定的刺胞动物-共生藻类关系。对 31 对共生关系（海葵、珊瑚和水母宿主中的五种共生藻类）的评估表明，感染可以在没有光合作用的情况下发生。建立了一种共生藻类的 UV 诱变方法，并利用该方法生成了 6 种可以感染这些宿主的光合作用突变体。没有光合作用，共生藻类就无法在海葵 Aiptasia 或水母 Cassiopea 中增殖，但可以在珊瑚 Acropora 的幼年息肉中增殖。在黑暗中 6 个月后，Brevium minutum 仍存在于 Aiptasia 中，这表明共生藻类的维持可以不依赖光合作用。对光合作用的操纵为刺胞动物-共生藻类共生关系提供了新的见解。
