Host-symbiont Compatibility in Cnidarian-algal Mutualisms
Open Access
- Author:
- Solanki, Priyanka Kanti
- Area of Honors:
- Biology
- Degree:
- Bachelor of Science
- Document Type:
- Thesis
- Thesis Supervisors:
- Todd C. LaJeunesse, Thesis Supervisor
Dr. Stephen Wade Schaeffer, Thesis Honors Advisor - Keywords:
- Symbiodinium
Cassiopeia
cnidarian host
symbiont
mutualism
host compatibility
partner specificity - Abstract:
- The mutualistic relationships between corals and symbiotic algae (dinoflagellates) are threatened by global warming, thus impacting the viability of coral reef ecosystems. The precarious relationship between the symbiont and host is dependent on partner specificity and compatibility. The photosynthetic dinoflagellates in the genus Symbiodinium microadriaticum forms an exclusive mutualistic relationship with the upside-down jellyfish Cassiopeia despite the prevalence of other potentially competitive Symbiodinium species in the host’s environment. Strobilation, a process of metamorphosis of the jellyfish, is a functional signal of the successful symbiotic infections. To better understand the partner compatibility of Cassiopeia xamachana, we tested the hypothesis that strobilation timing of the animals is dependent on the different symbiont species. Here we show that metamorphosis of the jellyfish was initiated by its native symbiont (S. microadriaticum), but strobilation was completed earlier by the non-native symbionts (S. minutum and S. trenchii). Symbiont cell densities per host increased over time and were highest for the native strain. This suggests that symbiont competition is important to specificity exhibited by these mutualistic symbioses in nature. Future studies to understand cell signaling would analyze host growth under direct competition between native and non-native symbiont strains, which would provide deeper insight into partner compatibility of the symbiont and its host. The ultimate understanding of partner compatibility between symbionts and hosts provide insights on the extent to which these symbioses may form new partnerships in response to climate change.