Host-dependent nitrogen recycling as a mechanism of symbiont control in Aiptasia
byCui Guoxin, Yi Jin Liew, Yong Li, Najeh Kharbatia, Noura I. Zahran, Abdul-Hamid Emwas, Victor M. Eguiluz, Manuel Aranda
Cui, Guoxin, Yi Jin Liew, Yong Li, Najeh Kharbatia, Noura I. Zahran, Abdul-Hamid Emwas, Victor M. Eguiluz, and Manuel Aranda. “Host-Dependent Nitrogen Recycling as a Mechanism of Symbiont Control in Aiptasia.” PLOS Genetics 15, no. 6 (June 24, 2019): e1008189. https://doi.org/10.1371/journal.pgen.1008189.
The symbiotic relationship with photosynthetic algae is key to the success of reef building corals in the nutrient poor environment of tropical waters. Extensive insight has been obtained from both physiological and “omics” level studies, yet, there are still gaps in our knowledge with respect to the metabolic interactions in this symbiotic relationship. In particular, the role of host in nitrogen utilization and its potential link to symbiont population control still remains unclear. Using a meta-analysis approach on publicly available RNA-seq data and isotope-labeled metabolomics, we demonstrate the presence of a negative-feedback cycle in which the host uses symbiont-derived organic carbon to assimilate its own waste ammonium. This host-driven nitrogen recycling process might serve as a molecular mechanism to control symbiont densities in hospite. The dependence of this regulatory mechanism on organic carbon provided by the symbionts explains the sensitivity of this symbiotic relationship to environmental stress.