Optimal nutrient exchange and immune responses operate in partner specificity in the cnidarian-dinoflagellate symbiosis
Significance Flexibility in the endosymbiotic Symbiodinium community could provide reef-building corals with the capacity to survive environmental change, but this may be restricted to compatible host-symbiont combinations. Therefore, determining the underlying molecular, cellular, and physiological processes of symbiont compatibility is of critical importance for elucidating the resilience and adaptability of coral reefs. We coupled gene expression data with high-throughput metabolite profiling to compare the effects on the sea anemone Aiptasia when colonized by the thermally tolerant, opportunistic, but comparatively unproductive Symbiodinium trenchii vs. the regular symbiont species, Symbiodinium minutum . This powerful approach revealed strong evidence that optimal nutritional exchange and the response to intracellular oxidative stress are important determinants in the success of novel cnidarian-dinoflagellate symbioses.