Seminar: Tingting Xiang – UNCC

UNC-CH’s Department of Marine Sciences is proud to host a seminar by Tingting Xiang. This event is scheduled for Wednesday, February 12th, at 12:30 pm in room G201 on the ground floor of Murray/Venable Hall at the University of North Carolina at Chapel Hill. This seminar will also be broadcast live to seminar room 222 at the Institute of Marine Sciences (IMS) in Morehead City, NC and online via Zoom (Meeting ID: 501-070-231).

Presenter Affiliation: Assistant Professor, UNC Charlotte

Title: Uncovering molecular mechanisms that govern dinoflagellate-coral symbiosis

Abstract: The mutualisms between unicellular dinoflagellate algae in the family Symbiodiniaceae and their cnidarian hosts, including corals and sea anemones, are essential for sustaining coral-reef ecosystems. In cnidarian-Symbiodiniaceae symbioses, algal endosymbiont population control within the host is needed to sustain a symbiotic relationship. However, the molecular mechanisms that underlie such population control are unclear. Here we show that a cnidarian host uses nitrogen limitation as a primary mechanism to control endosymbiont populations. Nitrogen acquisition and assimilation transcripts become elevated in symbiotic Breviolum minutum algae as they reach high-densities within the sea anemone host Exaiptasia pallida. These same transcripts increase in free-living algae deprived of nitrogen. Symbiotic algae also have an elevated carbon-to-nitrogen ratio and shift metabolism towards scavenging nitrogen from purines relative to free-living algae. Exaiptasia glutamine synthetase and glutamate synthase transcripts concomitantly increase with the algal endosymbiont population, suggesting an increased ability of the host to assimilate ammonium. These results suggest algal growth and replication in hospite is controlled by access to nitrogen, which becomes limiting for the algae as their population within the host increases.