Algae from Aiptasia egesta are robust representations of Symbiodiniaceae in the free-living state.

Many cnidarians rely on their dinoflagellate partners from the family Symbiodiniaceae for their ecological success. Symbiotic species of Symbiodiniaceae have two distinct life stages: inside the host, , and outside the host, . Several aspects of cnidarian-algal symbiosis can be understood by comparing these two life stages.

Heat Stress of Algal Partner Hinders Colonization Success and Alters the Algal Cell Surface Glycome in a Cnidarian-Algal Symbiosis.

Corals owe their ecological success to their symbiotic relationship with dinoflagellate algae (family Symbiodiniaceae). While the negative effects of heat stress on this symbiosis are well studied, how heat stress affects the onset of symbiosis and symbiont specificity is less explored. In this work, we used the model sea anemone, Exaiptasia diaphana (commonly referred to as Aiptasia), and its native symbiont, Breviolum minutum, to study the effects of heat stress on the colonization of Aiptasia by algae and the algal cell-surface glycome.

Limitations of Using Cultured Algae to Study Cnidarian-Algal Symbioses and Suggestions for Future Studies.

Much of our understanding of the cellular mechanisms underlying cnidarian-algal symbiosis comes from studying the biological differences between the partners when they are engaged in symbiosis and when they are isolated from one another. When comparing the in hospite and ex hospite states in Symbiodiniaceae, the in hospite state is represented by algae sampled from hosts, and the ex hospite state is commonly represented by cultured algae. The use of cultured algae in this comparison may introduce nutrition as a confounding variable because, while hosts are kept in nutrient-depleted conditions, culture media is nutrient rich and designed to facilitate algal growth.