RT Journal Article
SR Electronic
T1 Tissue- and cellular-level allocation of autotrophic and heterotrophic nutrients in the coral symbiosis – A NanoSIMS study
JF bioRxiv
FD Cold Spring Harbor Laboratory
SP 353250
DO 10.1101/353250
A1 Krueger, Thomas
A1 Bodin, Julia
A1 Horwitz, Noa
A1 Loussert-Fonta, Céline
A1 Sakr, Adrian
A1 Escrig, Stéphane
A1 Fine, Maoz
A1 Meibom, Anders
YR 2018
UL http://biorxiv.org/content/early/2018/06/21/353250.abstract
AB Corals access inorganic seawater nutrients through their autotrophic endosymbiotic dinoflagellates, but also capture planktonic prey through heterotrophic feeding. Correlating NanoSIMS and TEM imaging, we visualize and quantify the subcellular fate of autotrophic and heterotrophic C and N in the coral Stylophora pistillata using stable isotopes. Six scenarios were compared after 6h: autotrophic pulse (13C-bicarbonate, 15N-nitrate) in either unfed or regularly fed corals, and heterotrophic pulse (13C-, 15N-labelled brine shrimps) in regularly fed corals; each at ambient and elevated temperature. Host assimilation of photosynthates was similar under fed and unfed conditions, but symbionts assimilated 10% more C in fed corals. Photoautotrophic C was primarily channelled into host lipid bodies, whereas heterotrophic C and N were generally co-allocated to the tissue. Food-derived label was detected in some subcellular structures associated with the remobilisation of host lipid stores. While heterotrophic input generally exceeded autotrophic input, it was more negatively affected by elevated temperature. The reduced input from both feeding modes at elevated temperature was accompanied by a shift in the partitioning of C and N, benefiting epidermis and symbiont. This study provides a unique view on the nutrient partitioning in corals and highlights the tight connection of nutrient fluxes in symbiotic partners.