Symbiotic dinoflagellates in the family Symbiodiniaceae release mobile compounds (e.g., glucose, glycerol, amino acids, and lipids) to their host’s tissues. Little is known about how different symbionts affect quantitative and qualitative differences in these compounds. We tested how symbiont identity affects glycerol and glucose pools in the tissues of the sea anemone Exaiptasia pallida (“Aiptasia”). We infected symbiont-free anemones with three different symbiotic dinoflagellates: Breviolum minutum isolated from our Aiptasia stock, B. minutum isolated from a different Aiptasia population, and the free-living Effrenium voratum. We measured free glycerol and glucose levels in host tissues under photosynthetic conditions, as well as metabolite release by these algae when freshly isolated from Aiptasia and incubated in a host tissue homogenate. Anemone tissues containing the stock B. minutum accumulated glycerol at a higher symbiont cell-specific rate than those containing the alternative B. minutum or E. voratum (e.g., at 9 h of light incubation: stock B. minutum, 4.05 × 10−5 nmol per algal cell; alternative B. minutum, 0.90 × 10−5 nmol per algal cell; E. voratum: 1.14 × 10−5 nmol per algal cell). All symbiotic hosts accumulated glucose between 1 and 12 h of light incubation. At 12 h, the symbiont cell-specific glucose content was 6-fold higher in anemone tissues that contained stock B. minutum than in those containing the alternative B. minutum (1.73 × 10−6 vs. 0.30 × 10−6 nmol per algal cell, respectively). All freshly isolated algae released glycerol and glucose when incubated in host homogenate except E. voratum, which did not release glycerol. These trends mirrored those in hospite. Our results suggest that, on an algal cell-specific basis, B. minutum isolated from the same Aiptasia stock provided better nutritional support to the host than did the two other algae, though this was not reflected in colonization success, highlighting the underlying complexity of host-symbiont recognition and symbiosis establishment in the cnidarian-dinoflagellate partnership.

中文翻译：

---

共生物种对刺胞动物-甲藻共生模型中甘油和葡萄糖池的影响

Symbiodiniaceae 科的共生鞭毛藻向宿主组织释放可移动的化合物（例如，葡萄糖、甘油、氨基酸和脂质）。人们对不同的共生体如何影响这些化合物的数量和质量差异知之甚少。我们测试了共生体身份如何影响海葵 Exaiptasia pallida（“Aiptasia”）组织中的甘油和葡萄糖库。我们用三种不同的共生甲藻感染了无共生体的海葵：从我们的 Aiptasia 种群中分离出的 B. minutum，从不同的 Aiptasia 种群中分离出的 B. minutum，以及自由生活的 Effrenium v​​oratum。我们测量了光合条件下宿主组织中的游离甘油和葡萄糖水平，以及这些藻类在从 Aiptasia 新鲜分离并在宿主组织匀浆中孵育时释放的代谢物。与含有替代 B. minutum 或 E. voratum 的海葵组织相比，含有原种 B. minutum 的海葵组织以更高的共生细胞特异性速率积累甘油（例如，在 9 小时的光照下：原种 B. minutum，4.05 × 10−5 nmol 每个藻类细胞；替代 B. minutum，每个藻类细胞 0.90 × 10−5 nmol；E. voratum：每个藻类细胞 1.14 × 10−5 nmol）。所有共生宿主都在光照培养 1 到 12 小时之间积累了葡萄糖。在 12 小时时，含有原种 B. minutum 的海葵组织中的共生体细胞特异性葡萄糖含量比含有替代 B. minutum 的组织高 6 倍（1.73 × 10−6 vs. 0.30 × 10−6 nmol 每藻单元格）。所有新鲜分离的藻类在宿主匀浆中孵育时都会释放甘油和葡萄糖，但 E. voratum 除外，它不释放甘油。这些趋势反映了住院治疗的趋势。我们的结果表明，在特定藻类细胞的基础上，从相同的 Aiptasia 种群中分离出的 B. minutum 比其他两种藻类为宿主提供了更好的营养支持，尽管这并没有反映在定植成功中，突出了潜在的复杂性刺胞动物-甲藻伙伴关系中的宿主-共生体识别和共生建立。