The influence of photosymbiosis in Cassiopea xamachana regenerative success

The regenerative capacity of Scyphozoans (Phylum Cnidaria) has been relatively understudied. The model organism Cassiopea xamachana hosts photosynthetic dinoflagellate symbionts in the host’s motile amoebocyte cells. A handful of studies have reported regeneration in the polyps of C. xamachana, but the mechanisms underlying regeneration have not been fully explored. Despite undergoing drastic developmental changes when symbiotic, the effect of symbiont presence and species on host regeneration has never been explored. C. xamachana polyps were decapitated when aposymbiotic, and symbiotic with both a homologous and a heterologous symbiont species. Regeneration and asexual budding were observed, and EdU labeling was performed to observe patterns of cell proliferation in regenerating polyps. The presence of symbionts increased likelihood to regenerate, yet symbiont species did not affect success of regeneration. No blastema or dividing cells were observed, implying cell proliferation is not the primary mechanism behind regeneration in polyps of C. xamachana.