NSF Award
1555440
Intracellular associations between animal hosts and algal symbionts support important ecosystems like coral reefs. Despite the importance of these associations, there is limited understanding of basic aspects about how stable interactions between host and algal partners is achieved. This inhibits our ability to make informed decisions about the management of vulnerable ecosystems. For example, coral reefs experience periodic bleaching events that involve the breakdown of the symbiosis and jeopardize reef health, but the process of bleaching and subsequent recovery of the host are poorly understood. To protect our valuable reef resources, greater understanding of the cellular and genetic cross-talk between symbiotic partners is required. This project will elucidate key components of the conserved genetic regulatory pathways important in host:symbiont exchanges. As changes to ocean environments occur (e.g., increasing average seawater temperatures), it is imperative that details about how hosts support symbiont populations at the cellular and genetic level are fully understood. The project has a diverse suite of planned broader impacts including training of STEM undergraduates, involvement in a pre-college summer bridge program to increase diversity in STEM, partnerships with national leaders in incorporating undergraduate research in community colleges, and high impact community based learning opportunities.<br/><br/>The research will refine understanding of host:symbiont interactions through identification of major-effect symbiosis genes and genetic pathways. The proposed work takes advantage of unique properties of marine and freshwater sponge hosts and their algal partners to identify the molecular, genetic, cellular, and physiological interactions that occur. These properties allow control over the timing of symbiont infection, so that gene expression profiles can be correlated with events involved with symbiont contact, engulfment, recognition, intracellular migration, and repopulation. In a methodologically novel way, the research will create different combinations of hosts and algal partners to explore reasons why particular hosts become suitable habitat for particular symbionts while other hosts cannot support those symbionts. The project will explore how down-regulating gene expression can change dynamics of host:symbiont interactions, and combining field-based experiments, RNAseq, and advanced physiological, microscopic, and molecular tools, the research will identify common regulatory features of those interactions. The results will increase understanding of the habitat requirements of the symbiont, and the ability of the hosts to interact with different partners. The results will also help define the scope of change in the identity of symbiotic partners. In addition to intellectual contributions in the form of publications and presentations, this project will expand educational and research opportunities for pre-college, community college, and undergraduate students, particularly those from underserved backgrounds. The proposal will support high impact practices like course-based research and community-based learning in the context of an undergraduate curriculum, as well as community outreach through a multi-disciplinary faculty learning community and civic-engaged talks.
